Biosystems Zoneguard User manual

ZoneGuard

Single Channel Fixed Gas Detection System

Reference Manual

651 South Main Street

Middletown, CT 06457

Tel (860) 344-1079 (800) 711-6776

Fax (860) 344-1068

Version 2.3 30SEPT2005 p/n 13-063

Page 1

THE ZONEGUARD SINGLE CHANNEL FIXED GAS DETECTION SYSTEM HAS

BEEN DESIGNED FOR THE DETECTION AND MEASUREMENT OF

POTENTIALLY HAZARDOUS ATMOSPHERIC CONDITIONS

IN ORDER TO ASSURE THAT THE USER IS PROPERLY WARNED OF

POTENTIALLY DANGEROUS CONDITIONS, IT IS ESSENTIAL THAT THE

INSTRUCTIONS IN THIS MANUAL BE READ, FULLY UNDERSTOOD, AND

FOLLOWED.

ZoneGuard Operation Manual

Version 2.3

Part Number 13-063

Biosystems

651 South Main Street

Middletown, Connecticut 06457

No page or part of this operation manual may be reproduced in any form

without written permission of the copyright owner shown above.

Page 2

Table of Contents

SIGNAL WORDS .............................................................................................................4

WARNINGS......................................................................................................................4

CHAPTER 1. DESCRIPTION ........................................................................................5

1.1 ZONEGUARD CAPABILITIES ------------------------------------------------------------------------------------------------------5

1.2 METHOD OF SAMPLING -----------------------------------------------------------------------------------------------------------5

1.2.1 Wiring recommendations _________________________________________________________5

1.3 SENSOR OPTIONS -----------------------------------------------------------------------------------------------------------------5

1.4 CALIBRATION-----------------------------------------------------------------------------------------------------------------------5

1.4.1 One Button Auto Calibration_______________________________________________________5

1.5 DISPLAYS AND CONTROLS -------------------------------------------------------------------------------------------------------6

1.6 ALARM LOGIC----------------------------------------------------------------------------------------------------------------------6

1.7 SPECIAL MICROPROCESSOR FEATURES ---------------------------------------------------------------------------------------6

1.8 RELAYS AND OUTPUTS -----------------------------------------------------------------------------------------------------------6

1.8.1 VAC relay contacts______________________________________________________________6

1.8.2 VDC outputs___________________________________________________________________6

1.8.3 Output operation________________________________________________________________7

1.9 CLASSIFICATION FOR USE IN HAZARDOUS LOCATIONS-----------------------------------------------------------------------7

1.10 ZONEGUARD DESIGN COMPONENTS--------------------------------------------------------------------------------------------7

1.10.1 ZoneGuard controller ____________________________________________________________7

1.10.1.1 LED alarm light indicators......................................................................................................... 7

1.10.1.2 Audible alarm........................................................................................................................... 7

1.10.1.3 Detector display........................................................................................................................ 7

1.10.2 Remote detector assemblies ______________________________________________________7

1.10.2.1 Standard Detector housing ....................................................................................................... 7

1.10.2.2 Explosion-proof detector housing.............................................................................................. 7

CHAPTER 2. INSTALLATION AND BASIC OPERATION............................................8

2.1 INSTALLATION OVERVIEW --------------------------------------------------------------------------------------------------------8

2.2 ZONEGUARD CONTROLLER UNIT------------------------------------------------------------------------------------------------8

2.2.1 Controller PCBs ________________________________________________________________8

2.3 REMOTE DETECTOR ASSEMBLIES ----------------------------------------------------------------------------------------------8

2.3.1 Standard remote detector housing __________________________________________________8

2.3.2 Explosion-proof remote detector housing_____________________________________________8

2.4 SITING OF REMOTE DETECTORS ------------------------------------------------------------------------------------------------8

2.5 WIRING RECOMMENDATIONS ----------------------------------------------------------------------------------------------------9

2.5.1 Grounding_____________________________________________________________________9

2.6 CONNECTING REMOTE ALARM AND DETECTOR ASSEMBLIES WITH THE ZONEGUARD CONTROLLER -----------------9

2.6.1 Cautions______________________________________________________________________9

2.6.2 ZoneGuard controller connections __________________________________________________9

2.7 INITIAL SETUP----------------------------------------------------------------------------------------------------------------------9

2.8 NORMAL OPERATION--------------------------------------------------------------------------------------------------------------10

2.8.1 Overview of ZoneGuard operation __________________________________________________10

2.8.2 Turning the ZoneGuard on ________________________________________________________10

2.8.3 Turning the ZoneGuard off ________________________________________________________10

2.8.4 Start-up sequence ______________________________________________________________10

2.9 OPERATING MODES ---------------------------------------------------------------------------------------------------------------10

2.9.1 Text Only mode ________________________________________________________________10

2.9.2 Basic mode ___________________________________________________________________11

2.9.3 Changing operating modes________________________________________________________11

2.10 ENABLING OR DISABLING USE OF THE MODE BUTTON-----------------------------------------------------------------------11

CHAPTER 3 CALIBRATION.........................................................................................11

3.1 WARNINGS AND CAUTIONS CONCERNING VERIFICATION OF ACCURACY---------------------------------------------------11

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3.2 CALIBRATION OVERVIEW ---------------------------------------------------------------------------------------------------------11

3.3 VERIFICATION OF ACCURACY ----------------------------------------------------------------------------------------------------11

3.3.1 Fresh air "zero" in contaminated air _________________________________________________12

3.4 EFFECT OF CONTAMINANTS ON ZONEGUARD SENSORS --------------------------------------------------------------------12

3.4.1 Effects of contaminants on oxygen sensors ___________________________________________12

3.4.2 Effects of contaminants on combustible sensors _______________________________________12

3.4.2.1 Effects of high concentrations of combustible gas on the combustible sensor...........................12

3.4.3 Effects of contaminants on toxic gas sensors__________________________________________13

3.5 FUNCTIONAL (BUMP)TEST-------------------------------------------------------------------------------------------------------13

3.6 AUTO-CALIBRATION ---------------------------------------------------------------------------------------------------------------13

3.6.1 Fresh air "zero" auto-calibration sequence____________________________________________14

3.6.1.1 Reading “Too High” or “Too Low” for zero adjust......................................................................14

3.6.2 “Span” auto-calibration sequence___________________________________________________14

3.7 MANUAL CALIBRATION PROCEDURE --------------------------------------------------------------------------------------------15

3.7.1 Manual Fresh air "zero" through keypad buttons _______________________________________15

3.7.2 “Manual” span calibration through keypad buttons ______________________________________15

3.7.3 Manual true zero span calibration for oxygen sensors ___________________________________16

CHAPTER 4. SETTING ALARM LEVELS.....................................................................17

4.1 ALARM ADJUSTMENT SEQUENCE -----------------------------------------------------------------------------------------------17

4.2 RESTORING THE FACTORY DEFAULT ALARM SETTINGS ---------------------------------------------------------------------18

4.3 ALARM TEST FUNCTION ----------------------------------------------------------------------------------------------------------18

CHAPTER 5. ADVANCED FUNCTIONS.......................................................................19

5.1 ZONEGUARD ADVANCED FEATURES OVERVIEW------------------------------------------------------------------------------19

5.2 RE-SETTING THE CALIBRATION GAS CONCENTRATION ----------------------------------------------------------------------19

APPENDICES...................................................................................................................20

APPENDIX AZONEGUARD FIXED GAS DETECTION SYSTEM ORDERING INFORMATION----------------------------------------20

APPENDIX BZONEGUARD FIXED GAS DETECTION SYSTEM TECHNICAL SPECIFICATIONS------------------------------------21

APPENDIX CZONEGUARD DEFAULT ALARM SETTINGS ---------------------------------------------------------------------------22

APPENDIX DZONEGUARD SENSOR RANGES ---------------------------------------------------------------------------------------22

APPENDIX EZONEGUARD TOXIC SENSOR CROSS SENSITIVITY DATA-----------------------------------------------------------22

APPENDIX FZONEGUARD DIMENSIONAL DRAWINGS,ELECTRICAL SCHEMATICS,AND WIRING DIAGRAMS ----------------23

APPENDIX GCALIBRATION FREQUENCY --------------------------------------------------------------------------------------------26

BIOSYSTEMS STANDARD WARRANTY GAS DETECTION PRODUCTS....................27

Page 4

SIGNAL WORDS

The following signal words, as defined by ANSI Z535.4-1998, are used in the Zoneguard Reference Manual.

indicates an imminently hazardous situation which, if not avoided, will result in

death or serious injury.

indicates a potentially hazardous situation which, if not avoided, could result in

death or serious injury.

indicates a potentially hazardous situation, which if not avoided, may result in

moderate or minor injury.

CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if

not avoided, may result in property damage.

WARNINGS

1. The Zoneguard personal, portable gas detector has been designed for the detection of

dangerous atmospheric conditions. An alarm condition indicates the presence of a potentially life-threatening

hazard and should be taken very seriously. Failure to immediately leave the area during an alarm condition may

result in serious injury or death.

2. In the event of an alarm condition it is important to follow established procedures. The safest

course of action is to immediately leave the affected area, and to return only after further testing determines that the

area is once again safe for entry. Failure to immediately leave the area during an alarm condition may result in

serious injury or death.

3. The accuracy of the Zoneguard should be checked periodically with known concentration

calibration gas. Failure to check accuracy can lead to inaccurate and potentially dangerous readings.

4. The accuracy of the Zoneguard should be checked immediately following any known exposure

to contaminants by testing with known concentration test gas before further use. Failure to check accuracy can

lead to inaccurate and potentially dangerous readings.

5. A sensor that cannot be calibrated or is found to be out of tolerance should be replaced

immediately. An instrument that fails calibration may not be used until testing with known concentration test gas

determines that accuracy has been restored, and the instrument is once again fit for use.

6. Do not reset the calibration gas concentration unless you are using a calibration gas

concentration that differs from the one that is normally supplied by Biosystems for use in calibrating the

Zoneguard. Use of inappropriate calibration gas may lead to in accurate and potentially dangerous readings.

Customers are strongly urged to use only Biosystems calibration materials when calibrating the Zoneguard. Use of

non-standard calibration gas and/or calibration kit components can lead to dangerously inaccurate readings and

may void the standard Biosystems warranty.

7. Use of non-standard calibration gas and/or calibration kit components when calibrating the

Zoneguard can lead to inaccurate and potentially dangerous readings and may void the standard Biosystems

warranty.

Biosystems offers calibration kits and long-lasting cylinders of test gas specifically developed for easy Zoneguard

calibration. Customers are strongly urged to use only Biosystems calibration materials when calibrating the

Zoneguard.

8. Substitution of components may impair intrinsic safety.

9. For safety reasons this equipment must be operated and serviced by qualified personnel only.

Read and understand this reference manual before operating or servicing the Zoneguard.

10. A rapid up-scale reading followed by a declining or erratic reading may indicate a hazardous

combustible gas concentration that exceeds the Zoneguard’s zero to 100 percent LEL detectionrange. The safest

course of action is to immediately leave the affected area, and to return only after further testing determines that the

area is once again safe for entry.

Page 5

CHAPTER 1. DESCRIPTION

1.1 ZoneGuard capabilities

The ZoneGuard is a microprocessor based fixed gas

detection system designed to accept the input from a single

oxygen, combustible gas or toxic sensor. ZoneGuard

systems are designed to provide continuous round-the-clock

monitoring for a variety of common atmospheric hazards

including oxygen deficiency and/or enrichment, combustible

gases and vapors, and specific toxic contaminants such as

carbon monoxide (CO), hydrogen sulfide (H2S), sulfur

dioxide (SO2), chlorine (Cl2), chlorine dioxide (ClO2),

phosphine (PH3), and nitrogen dioxide (NO2). Sensors may

be integrally mounted to the ZoneGuard controller housing,

or located up to 50 feet away from the controller. Remote

detector assemblies are available in explosion-proof or non-

explosion-proof versions. (Combustible sensors may only

be mounted in explosion-proof sensor housings.) The unit is

designed for operation via 120VAC 60 Hz. external power

source.

Standard features include two independently adjustable

alarm setpoints, built-in loud audible alarm (85 dB at 3-feet),

easily-read, backlit LCD display, and bright LED alarm light

indicators for OK / power on (green), low alarm (amber) and

high alarm (red) conditions. Standard features also include

DPDT relay contacts (rated 5A at 250V non-inductive load)

for low and high alarm conditions. Optional accessories

include externally mounted high intensity strobe lights and

high intensity horn.

The ZoneGuard offers a choice of two modes of operation,

Text Only (“OK”), and Basic (numeric readings) to provide

the right amount of information for users with different skill

levels and monitoring requirements. Biosystems’ “One

Button” operating logic allows all procedures necessary for

normal day-to-day operation, including fully automatic

calibration adjustment, to be made through the use of the

single On/Off “Mode” button.

ZoneGuard sensors which are installed in explosion-proof

remote detector housings are classified by Underwriters

Laboratories, Inc. and the Canadian Standards Association

as Explosion-Proof for use in Class I, Division 1, Groups A,

B, C, D, E, F and G hazardous locations.

Each ZoneGuard system includes the controller with all

standard alarms, relays and electronics installed in a NEMA

4X fiberglass housing; sensor, mounting ears, calibration

adaptor, Reference Manual, Quick Reference Card, and

other standard accessories. Remote detector assemblies

include the remote sensor housing, the appropriate amplifier

board (installed in the remote detector housing), and sensor.

Note: Conduit, wire and other components necessary

to connect the remote detector assembly with the

instrument controller are not included and must be

ordered separately.

The ZoneGuard design includes many user selectable

features and is designed to be easily customized to meet

specific customer requirements. This chapter discusses

some of these special features as well as basic capabilities

used on a day-to-day basis.

1.2 Method of sampling

Once it has been connected to a power source and placed

in normal operation, the ZoneGuard system continuously

monitors for the hazard the sensor is designed to detect.

ZoneGuard sensors may be either integrally mounted to the

controller housing, or remotely located up to 50 feet away

from the controller. The atmosphere being measured

reaches the sensor by diffusing through a protective filter

into the sensor. Normal air movements are enough to carry

the sample to the sensor. The sensor reacts to changes in

the concentration of the hazard being measured. Values

are constantly updated and displayed on the ZoneGuard

controller LCD.

1.2.1 Wiring recommendations

For oxygen remote detectors use (minimum) 22 gauge

AWG, 6 conductor twisted-pair shielded with drain. For toxic

remote detectors use (minimum) 22 gauge AWG, 4

conductor twisted-pair shielded with drain. For combustible

remote detectors use 18 gauge AWG, 4 conductor twisted-

pair shielded with drain.

The maximum distance a ZoneGuard remote detector may

be located from the controller is 50 feet.

1.3 Sensor options

ZoneGuard systems can be configured to monitor for a

number of different atmospheric hazards. The hazard the

system is configured to detect is determined by the type of

sensor installed. The types of sensors currently available

include a galvanic oxygen (O2) sensor, a catalytic-bead

pellistor for LEL combustible gas, and substance-specific

electrochemical sensors for carbon monoxide (CO),

hydrogen sulfide (H2S), sulfur dioxide (SO2), chlorine (Cl2),

chlorine dioxide (ClO2), phosphine (PH3), and nitrogen

dioxide (NO2). Oxygen readings are given in percent-by-

volume, combustible gas readings in percent LEL, and toxic

gas readings in PPM (parts per million) or 0.1 PPM

concentrations.

1.4 Calibration

ZoneGuard systems have been designed for easy

verification of accuracy.

The accuracy of the Zoneguard

should be checked periodically with known

concentration calibration gas. Failure to check

accuracy can lead to inaccurate and potentially

dangerous readings.

1.4.1 One Button Auto Calibration

Biosystems’ “One Button” logic means that all normal day-

to-day operating procedures, including automatic calibration

adjustment, may be made through the use of the single

On/Off Mode button.

Calibration procedures are discussed in detail in

Chapter 3.

Page 6

1.5 Displays and controls

ZoneGuard systems include an 8-character LCD readout

located at the controller which is used to display gas

readings and other messages. Built-in LED alarm lights are

used to indicate “OK” / Power-on (green), “Low Alarm”

(amber), and “High Alarm” (red) conditions.

The On/Off “Mode” button is to initiate the automatic

calibration sequence and to control most other day-to-day

procedures. The button is located on the exterior of the

controller housing, on the underside of the case. Four

additional push-button controls (“-”, “+”, “Alarm” and “Cal”)

are located on the inside of the controller housing door.

These buttons are used for advanced procedures such as

changing operating modes, changing alarm setpoints,

adjusting calibration gas values, making optional setup

choices, and other advanced procedures.

1.6 Alarm Logic

The Zoneguard personal, portable

gas detector has been designed for the detection of

dangerous atmospheric conditions. An alarm condition

indicates the presence of a potentially life-threatening

hazard and should be taken very seriously. Failure to

immediately leave the area during an alarm condition

may result in serious injury or death.

In the event of an alarm condition it is important to

follow established procedures. The safest course of

action is to immediately leave the affected area, and

return only after further testing together with other

appropriate safety procedures determine that the area

is once again safe for entry.

ZoneGuard alarms are user adjustable and may be set

anywhere within the range of the specific sensor. When an

alarm set point is exceeded the audible alarm sounds, the

appropriate bright LED alarm light indicator are turned-on,

and (if equipped) the optional external strobe light(s) and/or

remote high intensity audible alarm are activated. (Any

external alarm devices controlled by means of the

ZoneGuard alarm relay contacts will also be activated.)

ZoneGuard alarms are normally of the self-resetting type.

When readings drop back below the pre-set alarm levels,

the instrument returns to normal operation, and the visual

and audible alarms cease.

It is possible to set ZoneGuard alarms so that they "latch".

In the latched condition, once an alarm occurs both visual

and audible alarms will continue to sound even after the

atmospheric hazard has cleared. The instrument must be

manually reset before the alarms are silenced.

Procedures for latching ZoneGuard alarms are given in

Chapter 4.

ZoneGuard systems equipped with toxic or combustible gas

sensors are provided with two levels of gas alarm: “Low”

(warning) and “High” (danger). Toxic and combustible

alarms are configured as “ascending”, meaning that they are

triggered when gas concentrations exceed the alarm

setpoints.

ZoneGuard systems equipped with oxygen sensors have

four levels of gas alarm, two “ascending” alarms (“Warning”

and “Danger”) for oxygen enrichment, and two “descending”

(“Warning” and “Danger”) alarms for oxygen deficiencies.

Descending alarms are activated when oxygen

concentrations drop below the alarm setpoints for oxygen

deficiency.

Note: “Warning” level alarms may be manually

acknowledged and silenced for a period of 10 minutes

by pressing the Mode button. If the alarm condition

continues to exist after 10 minutes has elapsed, the

“Warning” alarms will be reactivated. If the alarm

condition reaches the “Danger” level during this 10

minute period, the “Danger” level alarms will

immediately be activated regardless of whether or not

the “Warning” alarm has been silenced. “Danger” level

alarms may not be manually silenced.

The procedures for adjusting alarm setpoints are given

in Chapter 4.

1.7 Special microprocessor features

Several automatic programs prevent tampering and misuse

of the ZoneGuard by unauthorized persons. Each time the

detector is turned on, an electronic self-test is performed

that assures the user of proper performance.

Optional setup choices include latching alarms, changing the

concentration of the gas that is used during Auto Calibration

adjustment, as well as changing or restoring the factory

alarm settings by using the 4 push-buttons on the instrument

keypad. It is also possible to enable or disable use of the

external Mode button.

ZoneGuard software also includes an “Alarm Test” function

that can be used to automatically “ramp” readings

throughout the full range of the sensor. The “Alarm Test”

function is used to verify alarm setpoints as well as the

proper activation of the audible alarm, LED alarm light

indicators, optional strobe lights or horn, as well as other

alarm devices or peripheral equipment controlled by means

of the ZoneGuard relay contacts.

Chapters 4 and 5 describe how to use these advanced

technical features and setup choices in greater detail.

1.8 Relays and outputs

See Appendix F for ZoneGuard electrical schematics

and wiring diagrams.

1.8.1 VAC relay contacts

ZoneGuard systems include DPDT relay contacts for

warning (low) and danger (high) gas alarm conditions.

ZoneGuard relay contacts are rated at 5 Amp at 250 VAC,

non-inductive load.

1.8.2 VDC outputs

ZoneGuard systems also include +12 VDC outputs rated at

0.5 Amp for warning (low) and danger (high) gas alarm

conditions.

Page 7

CAUTION: ZoneGuard +12 VDC outputs may only be

used to provide power to remote alarm devices which

have been approved by Biosystems for use with the

ZoneGuard system. Use of non-approved devices may

cause damage to the ZoneGuard system, and void the

Biosystems Standard Warranty for Gas Detection

Products. Contact Biosystems Technical Service

Department at (860) 344-1079 for additional information

on approved remote alarm devices.

1.8.3 Output operation

ZoneGuard alarms are normally of the “self-resetting” type,

and will cease when readings drop back below the pre-set

alarm levels. ZoneGuard alarms may also be configured to

“latch” so that the alarms remain activated even after the

alarm condition has ceased. Once activated, a latched

alarm will continue to sound until the instrument is manually

reset by pressing the mode button.

The procedure for changing the alarm latch setting is

given in Chapter 4

If the gas concentration causes the activation of the low

(warning level) alarm, the audible alarm is activated, the low

level (amber) alarm LED illuminates, and the low alarm relay

is activated. Warning level alarms may be silenced and the

relay deactivated for a period of 10 minutes by pressing the

Mode button.

If the gas concentration causes the activation of the high

(danger level) alarm, the audible alarm is activated, the high

level (red) alarm LED illuminates, and the high alarm relay is

activated. High level alarms may not be manually silenced

by pressing the Mode button.

ZoneGuard systems are supplied with relays and outputs

preset with the following standard factory setup:

VAC relays:

Warning (low) alarm Normally energized (fail safe)

Danger (high) alarm Normally energized (fail safe)

12 VDC outputs:

Warning (low) alarm Normally de-energized

Danger (high) alarm Normally de-energized

1.9 Classification for use in hazardous

locations

ZoneGuard remote detector assemblies are available in

both explosion-proof and non-explosion-proof versions.

Explosion-proof version remote detector assemblies have

been submitted to Underwriters Laboratories, Inc. for

Classification per ULCas Explosion-Proof for use in Class I,

Division 1, Groups A, B, C, D, E, F, and G explosive

atmospheres.

1.10 ZoneGuard design components

See Appendix F for dimensional drawings, mounting

schematics, and wiring diagrams for the ZoneGuard

controller and remote detector assemblies.

1.10.1 ZoneGuard controller

The ZoneGuard controller unit is enclosed in a durable,

gasketed, fiberglass NEMA 4X case. The On/Off Mode

button is located on the exterior of the controller housing, on

the underside of the case. Four additional push-button

controls (“-”, “+”, “Alarm” and “Cal”) are located inside the

door of the controller housing.

1.10.1.1 LED alarm light indicators

ZoneGuard controllers include 3 bright system status and

alarm condition LED indicators; green for “OK” / Power On,

amber for “Warning”, and red for “Danger”.

1.10.1.2 Audible alarm

A loud (85 dB at 3 feet) built-in audible alarm is provided to

warn users of hazardous conditions. Optional remote

audible alarms and high intensity horns are also available.

1.10.1.3 Detector display

An 8-character LCD readout is used to display gas readings

and other information.

Readings, messages, and modes of operation are

discussed in Chapter 2.

1.10.2 Remote detector assemblies

Remote detector assemblies include sensor, sensor specific

amplifier board (installed in the remote detector housing),

and remote detector housing. Oxygen and toxic gas remote

detector assemblies are available in both “standard” (non-

explosion-proof) and “explosion-proof” versions. Remote

detector assemblies for combustible gas are only available

in explosion-proof housings.

Installation procedures are discussed in Chapter 2.

1.10.2.1 Standard Detector housing

“Standard” remote detector assemblies are housed in a

heavy-duty, nickel-coated, molded junction box. Not for use

in hazardous locations.

1.10.2.2 Explosion-proof detector housing

“Explosion-proof” remote detector assemblies are housed in

a heavy duty steel explosion-proof (Class I, Division 1,

Groups A, B, C, D, E, F, G) junction box with threaded lid.

Page 8

CHAPTER 2. INSTALLATION AND

BASIC OPERATION

2.1 Installation overview

Biosystems gas detection systems are fully tested and

calibrated before they leave the factory. However, after

installation we strongly recommend that full testing and

verification of proper operation is carried out before the

system is placed in normal service. Make sure all

ZoneGuard system elements and/or peripheral alarm,

notification, or control devices are properly installed

before connecting the system to a power source!

Make sure that the ZoneGuard system is disconnected

from the external power source before installing,

replacing, or handling ZoneGuard system components!

Repair of system components damaged as a result of

improper installation can be expensive! ZoneGuard

installation, initial setup, and / or system modification

should only be undertaken by individuals who are

qualified and authorized to do so. Call Biosystems’

Service Department at (860) 344-1079 if you need help

or have any questions.

2.2 ZoneGuard controller unit

The ZoneGuard controller unit is designed for wall mounting

in any convenient non-hazardous location where a suitable

power supply is available. ZoneGuard controller units are

designed for use with 120VAC, 60Hz. external power.

Note: ZoneGuard controller housing accessories

include a set of 4 external mounting brackets. Use of

these mounting brackets is optional. The controller

housing may be mounted directly to the wall or other

mounting surface by use of screws inserted through

apertures in 4 mounting wells located on the back of the

controller case, or by means of the external mounting

brackets, whichever is more convenient.

ZoneGuard controller housing accessories also include a ½”

NPT galvanized cable grab “gland”. If the cable connecting

the remote detector housing with the controller is run through

conduit, it will be necessary to remove the cable grab gland

and replace it with a threaded ½” NPT conduit bushing (not

provided). When making use of ZoneGuard relay contacts

to control or actuate external alarm devices it will be

necessary to remove the “hole-seal” from the bottom of the

controller case, and install the appropriate glands or

bushings. To prevent dust and water ingress all cable

entries and knockouts must be checked and sealed as

necessary.

2.2.1 Controller PCBs

The ZoneGuard controller includes a display PCB located

underneath the hinged controller case cover, and the relay

PCB located on a mounting plate inside the controller case.

In the case of ZoneGuard systems with integrally mounted

sensors, a sensor specific amplifier board is mounted onto

the relay PCB. In the case of ZoneGuard systems with

remote sensors, the amplifier board is located in the remote

detector housing.

The four push-buttons (“+”,“-”, “Alarm”, and “Cal”) used to

make use of advanced features and setup choices are

located on the display PCB on the inside of the controller

housing door.

2.3 Remote detector assemblies

Oxygen and toxic gas remote detector assemblies are

available in both “standard” (non-explosion-proof) and

“explosion-proof” housings. Remote detector assemblies for

combustible gas are only available in explosion-proof

housings.

ZoneGuard remote detector assemblies may be located up

to 50 feet away from the controller. Power is provided to

the remote detector by the ZoneGuard controller.

The ZoneGuard remote detector assembly contains a

factory installed, sensor specific amplifier PCB. The remote

detector assembly is labeled as to the type of hazard it is

designed to measure (i.e. H2S, CO, O2, etc.).

2.3.1 Standard remote detector housing

Sensors for the measurement of oxygen and toxic gas may

be installed either in explosion-proof or “standard” remote

detector housings.

Sensors that are housed in

“standard” remote detector housings may not be

installed in hazardous locations requiring an

“Explosion-Proof” classification.

2.3.2 Explosion-proof remote detector

housing

Explosion-proof remote detector housings can be installed in

Class I, Division 1 Groups A through G hazardous locations.

Explosion-proof remote detectors are installed in a heavy

duty stainless steel explosion-proof (Class I, Division 1,

Groups A through G) junction box with threaded lid.

ZoneGuard sensors for the measurement of

combustible gas may only be installed in explosion-

proof remote detector housings.

2.4 Siting of remote detectors

The specific placement of remote detector assemblies

should be a function of the type of area being monitored, the

type and source of atmospheric hazard being measured,

prevailing wind patterns, and other information.

Call Biosystems Technical Service Department at (860)

344-1079 for additional advice.

In general, for gases lighter than air, the detector should be

placed at a level slightly above the area where leaks are

likely to occur. For gases which are heavier than air the

detectors should be located close to floor level or in

inspection pits or ducts into which heavier than air gases

may collect or flow.

There are many circumstances which may modify this

general advice. For example, the molecular weight of

nitrogen (MW ≅28) is very close to that of air (MW ≅29).

Page 9

When nitrogen is at the same temperature as the air into

which it is introduced, it mixes readily, and tends to spread

evenly through the affected atmosphere. On the other hand,

if the nitrogen is under pressure, and then suddenly released

into the atmosphere, as the gas expands (going from higher

pressure to a lower pressure) it cools. Because the cooler

gas is now denser than the air into which it is being

introduced, it no longer mixes in as readily. Instead, the

nitrogen tends to fall to floor level, then spread laterally. In

this case remote detectors being used to monitor for oxygen

deficiency should be located near floor level in order to

detect the deficiency as quickly as possible.

The nearer in density to air a gas is, the more easily it will

flow with air due to draughts, ventilation etc. A compromise

approach for placement of detectors used to measure

gases which are only slighter lighter (such as carbon

monoxide) or heavier (such as hydrogen sulfide) than air is

to mount the detectors at a height as close as possible to

the breathing area of personnel being protected.

When installing detector assemblies it is important to ensure

that the sensor is not exposed to liquid or dust contamination

which would interfere with the passage of gas through the

protective filter into the sensor. Remote detector

assemblies should be placed so that the axis of the sensor

points straight downward. Splash deflectors should be used

when water or other liquid is chronically present in the area

where the detectors have been located.

2.5 Wiring recommendations

For oxygen remote detectors use (minimum) 22 gauge

AWG, 6 conductor twisted-pair shielded with drain. For toxic

remote detectors use (minimum) 22 gauge AWG, 4

conductor twisted-pair shielded with drain. For combustible

remote detectors use 18 gauge AWG, 4 conductor twisted-

pair shielded with drain.

The maximum distance a ZoneGuard remote detector may

be located from the controller is 50 feet.

Due to the relatively low signal levels carried by wiring

between gas detectors and their control unit, it is essential

not to run wire near high power electrical equipment. When

ZoneGuard systems are installed in environments which

contain high power electrical equipment it is usually best to

install the wire in conduit.

2.5.1 Grounding

Wire used to connect ZoneGuard remote detector

assemblies with the controller should always be with drain

lead. In order to reduce the chances for electromagnetic

interference (EMI), the screen (drain) of the wire should be

connected to the ground plate of the detector head (long

reach glands and/or the screen terminals should be used for

this purpose). Ground loops must be avoided! Grounding is

done through the normal circuit ground of the system.

2.6 Connecting remote alarm and

detector assemblies with the

ZoneGuard controller

2.6.1 Cautions

CAUTION: Make sure that the ZoneGuard system is

disconnected from the external power source before

installing, replacing, or handling installed ZoneGuard

system components!

CAUTION: Make sure the remote detector housing is

properly connected to the correct controller terminal

block connector as discussed below.

CAUTION: +12 VDC outputs may only be used to

provide power to remote alarm devices which have

been approved by Biosystems for use with the

ZoneGuard system. Use of non-approved devices may

cause damage to the ZoneGuard system, and void the

Biosystems Standard Warranty for Gas Detection

Products. Contact Biosystems Technical Service

Department at (860) 344-1079 for additional information

on approved remote alarm devices.

2.6.2 ZoneGuard controller connections

Electrical connections and wiring diagrams for the

ZoneGuard controller are shown in Appendix F.

Full wiring schematics are available on the Biosystems

website or by contacting Biosystems directly.

Connections are by screw terminal blocks located on the

mounting plate and relay PCB located in the ZoneGuard

controller. Warning (Low) and Danger (High) VAC output

relays are DPDT, are isolated from the system power

supply, and are rated at 5 Amp, 250VAC, non-inductive.

Warning (Low) and Danger (High) VDC outputs (+12 VDC

at 0.5 Amp) may only be used to provide power to remote

alarm devices which have been approved by Biosystems for

use with ZoneGuard systems.

2.7 Initial setup

1. Make sure the controller is not connected to any other

peripheral or external equipment or alarm devices.

2. Disconnect the built-in “loud” 85 dB audible alarm.

3. Make sure any other alarm or notification devices

controlled by means of the ZoneGuard relay contacts

are disconnected or turned off.

4. Connect mains power to the controller.

5. Connecting the ZoneGuard system with mains power

will cause the detector to turn on in normal operation.

The green “OK / Power On” LED indicator should be lit

and the LCD display should be on. The LCD display

should show a sequence of start-up screens as the

detector goes through a self test sequence, followed by

the current gas level readings. The low or high LED

alarm indicators, optional strobe lights, remote audible

alarms, and other devices connected to may be

activated while the sensor is stabilizing.

Page 10

Note: The ZoneGuard system is designed so that in

the event of a power interruption, the instrument will

automatically turn itself back on. To turn the system

off it will be necessary to hold down the Mode button

until the display goes blank. When the Mode button

is released the display will indicate “OFF”.

6. Allow the readings to stabilize fully.

Note: Combustible and oxygen sensors may take up

to an hour after power is applied to the system to

stabilize fully. Carbon monoxide, hydrogen sulfide,

sulfur dioxide and phosphine may take up to 2

hours. Chlorine, chlorine dioxide, and nitrogen

dioxide sensors may take up to 12 hours.

7. If readings are still in alarm, the ZoneGuard should be

fresh air zeroed. Since the amount of adjustment

required at the time of initial setup may be large, it is

usually better to make a “manual” fresh air zero

adjustment. To do a manual fresh air zero, make sure

the sensor is currently located in fresh air, then press

the “Cal” button to enter the “Zero Adjust Mode”. The

display should show the message “Zero Gas”. Press

the Cal button once more to automatically make a fresh

air zero adjustment. (The complete procedures for

zero and span calibration are discussed in Chapter

3.)

8. Reconnect the 85dB audible alarm and any other alarm

devices which were turned off or disconnected prior to

“powering up” the ZoneGuard system.

The ZoneGuard system must be properly calibrated as

discussed in Chapter 3 at the time of initial installation

before the system is put into normal service.

2.8 Normal operation

2.8.1 Overview of ZoneGuard operation

The ZoneGuard offers a choice of two modes of operation,

Text Only, (“OK”) and Basic, (numeric readings). Mode

selection should be determined based on how much

information is required, the skill level of the user, and the

nature of the environment in which the ZoneGuard system is

installed.

2.8.2 Turning the ZoneGuard on

The black switch located on the bottom of the exterior of the

ZoneGuard controller housing is called the Mode button. It

is used to turn the ZoneGuard on and off, as well as to

control most other operations of the instrument. Press and

hold the Mode button for one second to turn the ZoneGuard

on.

2.8.3 Turning the ZoneGuard off

Turn the ZoneGuard off by pressing and holding the Mode

button until the LCD goes blank. When the button is

released the LCD will display the message “OFF”.

2.8.4 Start-up sequence

After the ZoneGuard has been turned on, it will automatically

go through an electronic self test and start-up sequence that

takes approximately twenty seconds. During start-up the

LCD display will show several messages or "screens" in

sequence. The first screen displays the software version

number: The second shows the type of sensor installed.

Additional screens will briefly appear indicating the current

low (warning) and high (danger) alarm setpoints. For

instance, a ZoneGuard for carbon monoxide being operated

in the Basic mode would show the following sequence of

factory installed (default) alarm set points when the

instrument is first turned on. (Note: The software version

installed in your ZoneGuard may differ with that shown

below.)

→→

→

At the conclusion of the startup sequence, the screen will

cycle back and forth between the current gas readings

screen and the sensor identification screen.

↔

Note: LCD screens indicating readings or alarm

setpoints include the measurement units being used. In

the case of toxic gas the last three characters will

indicate “PPM” (parts-per-million). In the case of

combustible gas (LEL) and oxygen the last three

display characters will indicate “PCT” (percent).

The alarm set-point screens are omitted when the

instrument is turned on while in the “Text Only” mode.

2.9 Operating modes

Two operating modes provide ZoneGuard users with the

right amount of information to meet their monitoring needs.

The ZoneGuard is designed to be as simple or as

sophisticated as the job that needs to be done.

2.9.1 Text Only mode

The simplest mode of operation is the “Text Only” mode. In

this mode, during normal operation the LCD screen displays

an “OK” message rather than numerical readings as long as

no alarms are present. The “OK” screen alternates with the

sensor identification screen.

↔

During an alarm condition (when the sensor readings exceed

a pre-set alarm level), the ZoneGuard will show readings as

a numerical value, activate the appropriate LED alarm light,

sound the audible alarm, and (if equipped) activate the

optional high intensity strobe light(s), remote audible alarm,

Page 11

and/or other alarm or notification devices controlled by the

ZoneGuard relay contacts.

↔

ZoneGuard alarms are normally self-resetting. When

readings drop back below the pre-set alarm levels, the

screen returns to the "OK" indication, and visual and audible

alarms cease.

2.9.2 Basic mode

Basic mode provides numerical readings during normal

operation.

↔

2.9.3 Changing operating modes

To change operating modes, with the instrument running

open the door of the controller housing to access the four

mini-push-buttons, and simultaneously press and hold the

"+" and "-" buttons until the word “MODE” is displayed.

Each time the operating mode is changed the display screen

will briefly indicate which operating mode “TEXT” or “BSIC”

(Basic) has been selected.

Note: Shifting modes or otherwise reprogramming the

instrument should only be done by employees who are

authorized to do so.

2.10 Enabling or disabling use of the

Mode button

Most day-to-day operating procedures (such as automatic

calibration adjustment) are normally made by using the

On/Off Mode button. It is possible to disable the use of the

Mode button. Once disabled, the Mode button may no

longer used for any purpose. To restore normal functions,

the Mode button must be re-enabled.

To enable or disable use of the Mode button press and hold

down the “+” key while the ZoneGuard system is in normal

operation. The display will show the message “MODE OFF”

or “MODE ON” to indicate when the procedure of enabling

or disabling the Mode button is complete.

CHAPTER 3 CALIBRATION

3.1 Warnings and cautions concerning

verification of accuracy

The accuracy of the Zoneguard

should be checked immediately following any known

exposure to contaminants by testing with known

concentration test gas before further use. Failure to

check accuracy can lead to inaccurate and potentially

dangerous readings.

A sensor that cannot be calibrated

or is found to be out of tolerance should be replaced

immediately. An instrument that fails calibration may

not be used until testing with known concentration test

gas determines that accuracy has been restored, and

the instrument is once again fit for use.

Do not reset the calibration gas

concentration unless you are using a calibration gas

concentration that differs from the one that is normally

supplied by Biosystems for use in calibrating the

Zoneguard. Use of inappropriate calibration gas may

lead to in accurate and potentially dangerous readings.

Customers are strongly urged to use only Biosystems

calibration materials when calibrating the Zoneguard.

Use of non-standard calibration gas and/or calibration

kit components can lead to dangerously inaccurate

readings and may void the standard Biosystems

warranty. Use of non-standard calibration gas

and/or calibration kit components when calibrating the

Zoneguard can lead to inaccurate and potentially

dangerous readings and may void the standard

Biosystems warranty.

Biosystems offers calibration kits and long-lasting

cylinders of test gas specifically developed for easy

Zoneguard calibration. Customers are strongly urged

to use only Biosystems calibration materials when

calibrating the Zoneguard.

3.2 Calibration overview

The ZoneGuard gas detection system has been designed

for easy calibration. A single button, the on / off Mode

button, is used to initiate the “Auto-Calibration” sequence,

and automatically make all calibration adjustments.

It is also possible to manually calibrate the instrument by

using simple push-button controls located on the inside of

the door of the ZoneGuard controller housing.

“One-Button Auto-Cal” procedures are discussed in

Section 3.6. Manual calibration procedures are

discussed in Section 3.7.

3.3 Verification of accuracy

To verify accuracy, first place the Zoneguard in Basic Mode

so that readings are given in numbers. See section 2.9.3

for instructions on changing operating modes.

Page 12

Verification of accuracy for a Zoneguard equipped with an

O2sensor is a one-step procedure. Simply provide the

sensor with a known source of fresh air and verify that the

display reads 20.9% oxygen. If the display shows anything

besides 20.9% while exposed to a known source of fresh

air, it must be fresh air calibrated as discussed below in

section 3.6.1.

Verification of accuracy for a Zoneguard equipped with

either a combustible gas / LEL sensor or any toxic sensor is

a two-step procedure.

Step one is to provide the sensor with a known source of

fresh air and verify that the display shows “0 PCT” for LEL

units or “0 PPM” for toxic units. If an instrument equipped

with an LEL or toxic sensor shows anything besides “0” while

exposed to a known source of fresh air, it must be fresh air

calibrated as discussed below in section 3.6.1. If the

ZoneGuard is located in an area in which the air may not be

fresh, see section 3.3.1 below for instructions on fresh air

“zero” calibrations in contaminated air.

Step two is to test sensor response by exposing the sensor

to appropriate test gas of known concentration. This is

known as a functional (bump) test. Readings are

considered to be accurate when the display shows a reading

between 90% and 120% of the expected values as given on

the calibration gas cylinder. If readings are accurate, there

is no need to adjust your gas detector. See section 3.5 for

explicit functional/bump test instructions.

If the readings are inaccurate, the instrument must be

calibrated before further use as discussed in section 3.6.

Biosystems offers calibration kits and long lasting cylinders

of test gas specifically developed for easy ZoneGuard

calibration. Customers are urged to use Biosystems

calibration materials when calibrating their ZoneGuard

detectors.

3.3.1 Fresh air "zero" in contaminated air

The fresh air "zero" for all types of sensors must be done

while the sensor is located in fresh, uncontaminated air. In

this procedure the instrument automatically adjusts its

readings to match the concentrations present in fresh air.

Fresh air should contain 20.9% oxygen, 0% LEL combustible

gas, and 0 parts-per-million toxic gas.

If the atmosphere in which the ZoneGuard sensor is located

is not fresh, or if it is not certain whether or not the air is

contaminated, special procedures are required. In this case,

the zero adjustment must be made while the sensor is

exposed to contaminant free atmosphere by means of a

cylinder of “Zero Air” which contains 20.9% oxygen, 79.1%

nitrogen and no contaminants. This gas is supplied to the

sensor and the instrument may then be fresh air “zero”

calibrated as discussed in section 3.6.1.

3.4 Effect of contaminants on ZoneGuard

sensors

The atmosphere in which the ZoneGuard monitor is being

used can have an effect on the sensor. Sensors may be

poisoned or suffer degraded performance if exposed to

certain substances.

Caution: The accuracy of the ZoneGuard should be

checked immediately following any known exposure to

contaminants by testing with known concentration test

gas before further use.

The ZoneGuard is available with three basic types of

sensors: oxygen, combustible gas (LEL), and

electrochemical toxic. Each type of sensor uses a slightly

different detection principle. The kinds of conditions that

affect the accuracy of the sensors vary from one type of

sensor to the next.

3.4.1 Effects of contaminants on oxygen

sensors

Oxygen sensors may be affected by prolonged exposure to

"acid" gases such as carbon dioxide. The oxygen sensors

used in Biosystems instruments are not recommended for

continuous use in atmospheres which contain more than 25

% CO2.

3.4.2 Effects of contaminants on

combustible sensors

Combustible sensors may be affected by exposure to

substances containing silicone (found in many lubricants and

hydraulic fluids), the tetra-ethyl-lead in "leaded" gasoline,

and halogenated hydrocarbons (Freons®, or solvents such

as trichloroethylene and methylene chloride). High

concentrations of hydrogen sulfide may also damage the

sensor.

For a comprehensive list of known LEL sensor poisons,

see the last paragraph of the Biosystems Standard

Warranty at the end of this manual.

If sensitivity of the combustible sensor is lost due to

poisoning, it tends to be lost first with regards to methane. A

partially poisoned sensor might still respond accurately to

propane while showing a dangerously reduced response to

methane.

Biosystems’ “Equivalent” calibration gas mixtures have been

developed to eliminate this potentially dangerous source of

calibration error. Biosystems’ “Equivalent” mixtures are

based on methane, so any loss of sensitivity to methane is

detected (and can be corrected) immediately. Biosystems

offers several different “Equivalent” combustible calibration

gas mixtures for use in various monitoring applications.

Please contact Biosystems’ Service Department at (800)

711-6776 for help in deciding which calibration gas mixture

to specify for use.

Using Biosystems brand calibration gas insures that

proper sensitivity is maintained over the life of the

sensor.

3.4.2.1 Effects of high concentrations of

combustible gas on the combustible

sensor

The accuracy of combustible sensors may also be affected

by exposure to high concentrations of combustible gas. To

minimize the chance for damage or loss of sensitivity to the

combustible sensor, the ZoneGuard system is designed to

Page 13

"alarm latch" whenever the concentration of combustible gas

exceeds 100 percent LEL. Under these conditions the

combustible gas reading will show an “X” to indicate an over-

limit condition. The audible and visual alarms will sound

continuously until the instrument is manually reset by turning

it off, then turning the instrument back on.

A combustible sensor overrange

alarm indicates a potentially explosive atmosphere.

Failure to leave the area immediately may result in

serious injury or death!

Note: If the over limit condition still exists at the time

the instrument is turned back on, the ZoneGuard

system will revert to the over-limit alarm-latch

condition. Make sure the alarm condition has

truly cleared before attempting to make an auto-zero

adjustment. Auto-zero adjustments may only be made

when the ZoneGuard sensor is located in air that is

known to be fresh. Accuracy of the combustible gas

sensor should be verified by exposure to known

concentration test gas before further use.

Note: The combustible sensor used in the ZoneGuard

design requires the presence of oxygen in order to

detect combustible gas. The accuracy of the

combustible sensor may be affected if the instrument is

used in oxygen deficient atmospheres.

Any rapid up-scale reading followed

by a rapid declining or erratic reading may indicate a

gas concentration beyond the upper scale limit which

may be hazardous.

3.4.3 Effects of contaminants on toxic gas

sensors

Biosystems “substance-specific” electrochemical sensors

used to measure toxic gases such as CO, H2S, SO2, Cl2,

ClO2, PH3, and NO2have been carefully designed to

minimize the effects of common interfering gases.

“Substance-specific” sensors are designed to respond only

to the gases they are supposed to measure. The higher the

specificity of the sensor the less likely the sensor will be

affected by exposure to other gases which may be

incidentally present. For instance, a “substance-specific”

carbon monoxide sensor is deliberately designed not to

respond to other gases which may be present at the same

time, such as hydrogen sulfide or methane.

Even though care has been taken to reduce cross-

sensitivity, some interfering gases may still have an effect on

toxic sensor readings. In some cases the interfering effect

may be “positive” and result in readings which are higher

than actual. In some cases the interference may be

negative and produce readings which are lower than actual.

Cross sensitivity of ZoneGuard toxic sensors to

common interfering gases is listed in Appendix E.

3.5 Functional (bump) test

Note: The functional (bump) test is only used on

instruments equipped with a combustible gas / LEL or

toxic gas sensor. For further details on verifying the

accuracy of an instrument with an O2sensor, see

section 3.3.

To perform a Functional (bump) test,

1. Place the Zoneguard in Basic Mode so that readings are

given in numbers.

2. Make sure the sensor is located in fresh air. If you are

not certain the air is fresh, use a cylinder of Zero Air to

supply atmosphere to the sensor.

3. Verify that the readings match the concentrations

present in fresh air. Instruments equipped with an LEL

sensor or any of the toxic gas sensors should read “0”.

If necessary, fresh air “zero” calibrate the instrument

using the procedures discussed in Section 3.6.1.

4. Screw the regulator into the cylinder and connect it to

the detector using the short section of tubing and the

calibration adapter. The regulator will automatically

begin flowing calibration gas at the correct flow rate as

soon as it is screwed into the cylinder of gas.

5. The instrument will display the sensor readings as they

rise. When they have stabilized at their highest value,

note the readings. Readings are considered to be

accurate when the display is between 90% and 120% of

the expected values as given on the calibration gas

cylinder. If readings are accurate, there is no need to

span calibrate the detector.

Readings that are considered inaccurate indicate the

instrument must be adjusted using the “span”

calibration procedures discussed in Section 3.6 before

further use.

3.6 Auto-calibration

Biosystems “One-Button Auto-Calibration” mode may be

used to verify accuracy any time during normal operation

while the instrument is being used in the Basic operating

mode. Press the Mode button 3 times in rapid sequence to

initiate the “Auto-Calibration” sequence. Sensor

adjustments are made automatically in Auto Calibration

mode.

Auto-calibration is a one step procedure for instruments

equipped with an oxygen sensor. If the detector doesn’t

read 20.9 PCT in a known fresh air environment, perform

the fresh air “zero” calibration as described in section 3.6.1.

Auto-calibration is a two step procedure for instruments

equipped with either a combustible gas / LEL sensor or a

toxic gas sensor. In the first step the sensor is exposed to

fresh air and a "zero" adjustment is made automatically as

discussed below in section 3.6.1. The second step is the

sensor response or "span" calibration adjustment. In this

step the accuracy of the ZoneGuard sensor is established by

exposing it to known concentration calibration gas as

discussed below in section 3.6.2. The sensitivity or “span” is

automatically adjusted.

Page 14

3.6.1 Fresh air "zero" auto-calibration

sequence

The “One Button” fresh air zero procedure may only be done

while the ZoneGuard system is being operated in the Basic

operating mode.

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Make sure the ZoneGuard system has been turned on

and operating for a sufficient period of time for the

sensor readings to have stabilized fully before initiating

auto-calibration procedures.

If the sensor has just been replaced, the ZoneGuard

should be turned on and allowed to stabilize for the

following period of time prior to performing any of the

calibration options.

Sensor Stabilization Period

Oxygen 1 hour

LEL 5 minutes

All Toxic sensors

available for ZoneGuard 15 minutes

3. Make sure the sensor is located in an area where the air

is known to be fresh or provide fresh air to the sensor

with a cylinder of “Zero Air”. See section 3.3.1 for more

details on using a “Zero Air” cylinder during the Fresh Air

“zero” calibration.

4. Press the Mode button 3 times within two seconds. This

will "wake up" the instrument from normal operation,

and put it into the “Auto-Calibration” mode. A screen

will briefly display the message “ZERO MODE”.

↔

5. Press the Mode button within five seconds to initiate the

fresh air adjustment. (If the Mode button is not pushed

within 5 seconds, the instrument will return to normal

operation.)

6. The screen will show the message “ZERO WAIT” while

the adjustment is being completed.

↔

7. After successful completion of the “zero” auto-

calibration, the display will prompt you with the message

“SPAN MODE” to continue with a span calibration

adjustment.

Span calibration is covered in detail below in section

3.6.2.

3.6.1.1 Reading “Too High” or “Too Low” for

zero adjust

To reduce the chances of the ZoneGuard being

inadvertently zeroed in contaminated air, only small

adjustments are allowed through the use of the “One Button”

auto-zero sequence. If the necessary adjustments are too

large the display will indicate that the ZoneGuard “CANT

ZERO”. In this case the instrument must be fresh air zeroed

using the “Cal” button on the instrument keypad and

procedures discussed in Section 3.7.1.

Once the instrument has been successfully zeroed using the

“Cal” button, subsequent calibration adjustments may be

made using the Mode button and “One Button Auto Cal”

logic discussed in this section.

3.6.2 “Span” auto-calibration sequence

After successful completion of the FRESH “zero” auto-

calibration adjustment, instruments equipped with either a

combustible gas / LEL sensor or a toxic gas sensor will

automatically move on to “SPAN MODE”.

↔

1. Press the Mode button within 5 seconds to initiate

“span” auto-calibration. The screen will show “FLOW

GAS” and will continue to display this screen until it

determines that calibration gas has been applied. If the

Mode button is not pushed within five seconds a span

calibration adjustment will not be made, and the

instrument will be returned to normal operation.

Note: It is possible to exit the auto-calibration mode at

any time prior to completion by pressing and holding

down the Mode button to turn the instrument off.

↔

2. Screw the regulator into the cylinder and connect it to

the detector using the short section of tubing and the

calibration adapter. The regulator will automatically

begin flowing calibration gas at the correct flow rate as

soon as it is screwed into the cylinder of gas.

Make sure the regulator, cylinder

seating surfaces and threads are clean and dry before

attaching the regulator to the cylinder of gas.

Introduction of contaminants through the regulator

fittings may alter or degrade the concentration of the

gas contained in the cylinder and may lead to

inaccurate and potentially dangerous gas readings.

3. The instrument will display the sensor readings as they

rise. When they have stabilized at their highest value,

the instrument will note the response and, if necessary,

adjust the readings to match the concentration of gas

being used to calibrate the detector. (The instrument

will beep as the adjustment is being made.)

Use of non-standard calibration gas

and/or calibration kit components when calibrating the

ZoneGuard may lead to dangerously inaccurate

readings and may void the standard Biosystems

warranty.

4. When span adjustment has been completed, the display

will show the message “DONE”.

Page 15

Note: Make sure the calibration adaptor and all other

fittings have been removed from the detector before it

is returned to service.

3.7 Manual calibration procedure

It is also possible to calibrate the ZoneGuard manually using

the four buttons on the instrument keypad.

3.7.1 Manual Fresh air "zero" through

keypad buttons

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Make sure the ZoneGuard system has been turned on

and operating for a sufficient period of time for the

sensor readings to have stabilized fully before initiating

manual calibration procedures.

If the sensor has just been replaced, the ZoneGuard

should be turned on and allowed to stabilize for the

following period of time prior to performing any of the

calibration options.

Sensor Stabilization Period

Oxygen 1 hour

LEL 5 minutes

All Toxic sensors

available for ZoneGuard 15 minutes

3. Make sure the sensor is located in fresh, contaminant

free atmosphere or use a cylinder of Zero Air to supply

atmosphere to the sensor.

4. Press the keypad button marked "Cal". The “GAS

ZERO” calibration message will appear on the

instrument LCD.

↔

5. Press “Cal” to automatically zero the instrument. The

LCD will show the message “ZERO WAIT” while the

adjustment is being made.

↔

6. After completion of the zero adjustment the ZoneGuard

will automatically return to the current gas readings

screen.

7. The manual fresh air zero adjustment can be canceled

at any time prior to completion by pressing the Mode

button. Pressing the Mode button causes the calibration

values in the memory to remain unchanged from the

last time a fresh air adjustment was made. An

information screen is displayed briefly which verifies that

the zero values have not been changed. The instrument

will then return to normal operation.

↔

3.7.2 “Manual” span calibration through

keypad buttons

Span calibration procedures using buttons on the instrument

keypad are only necessary when the adjustment necessary

to restore accuracy is outside the permissible window of

adjustment for “One Button Auto Calibration” procedures.

Span calibration using the keypad buttons may only be done

while in the Basic operating mode.

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Make sure the ZoneGuard system has been turned on

and operating for a sufficient period of time for the

sensor readings to have stabilized fully before initiating

manual calibration procedures.

If the sensor has just been replaced, the ZoneGuard

should be turned on and allowed to stabilize for the

following period of time prior to performing any of the

calibration options.

Sensor Stabilization Period

Oxygen 1 hour

LEL 5 minutes

All Toxic sensors

available for ZoneGuard 15 minutes

3. Turn the instrument off by pressing and holding the

Mode button.

4. While holding down the "Cal" button, press the Mode

button to turn the ZoneGuard back on. A screen

showing the message “SPAN” will be displayed which

alternates with the sensor readings.

↔

Press the Mode button at any time to cancel the calibration.

5. Screw the regulator into the cylinder and connect it to

the detector using the short section of tubing and the

calibration adapter. The regulator will automatically

begin flowing calibration gas at the correct flow rate as

soon as it is screwed into the cylinder of gas.

6. Allow the readings to stabilize. When the readings

stabilize, use the "+" and "-" keys to raise or lower the

readings to match the concentration printed on the

calibration cylinder label.

7. Make sure the correct cylinder of gas is attached before

attempting to adjust the span! If the concentration of

gas reaching the sensor is too low to allow the

instrument to be adjusted, or if the wrong type of gas is

applied to the sensor being adjusted, the alarms will be

Page 16

activated and a screen will be displayed indicating that

the instrument “CANT SPAN”. Pressing the Mode

button clears the “CANT SPAN” message and returns

the instrument to normal operation.

↔

In the event that a “CANT SPAN” message is displayed,

verify the type and concentration of the gas being used is

correct for the sensor being calibrated, and replace the

cylinder if necessary. Verify that the flow rate of the

regulator is 1.0 lpm. If the "CANT SPAN" message is

repeated it may indicate that the sensor is unresponsive,

or dead, and requires replacement.

8. When span calibration has been completed, press and

hold the "Cal" button down until the LCD screen

indicates that calibration is complete by showing the

message “DONE”. The ZoneGuard will then turn itself

off.

Caution: The “Cal” button must be held down until

the screen indicates that span calibration has been

successfully completed.

If the button is released before this message is displayed,

span values will not be updated, and remain unchanged

from the last time a span calibration was successfully

completed.

Pressing the Mode button at any time cancels the manual

span calibration procedure. A screen will announce “NO

SAVE” after which the instrument will turn itself off.

↔

A sensor that cannot be calibrated

or is found to be out of tolerance should be replaced

immediately. An instrument that fails calibration may

not be used until testing with known concentration test

gas determines that accuracy has been restored, and

the instrument is once again fit for use.

Pressing the Mode button at any time during the span

adjustment cancels the procedure, and causes the

calibration values in memory to remain unchanged from the

last time a span calibration adjustment was made.

3.7.3 Manual true zero span calibration for

oxygen sensors

Note: During normal operation of a ZoneGuard system

for the detection of oxygen, the only calibration

adjustment necessary is the automatic fresh air “zero”

procedure as discussed in Section 3.6.1.

Following reinitialization of the instrument, or in cases where

the ZoneGuard is being used to monitor oxygen levels that

are close to 0.0%/volume and increased accuracy near 0 is

required, the ZoneGuard may be manually span adjusted. A

cylinder of calibration gas containing 100% nitrogen and no

oxygen is necessary for this calibration routine.

If the ZoneGuard is not span adjusted following

reinitialization, message screens will indicate “NEED CAL”

when the instrument is next turned on.

↔

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Make sure the ZoneGuard system has been turned on

and operating for a sufficient period of time for the

sensor readings to have stabilized fully before initiating

manual calibration procedures. If the oxygen sensor

has just been replaced, the ZoneGuard for oxygen

should be turned on and allowed to stabilize for one

hour prior to performing any of the calibration options.

3. Turn the instrument off by pressing and holding the

Mode button until Off is displayed.

4. While holding down the "Cal" button, press the Mode

button to turn the ZoneGuard back on. Release the

button when the word “SPAN” appears. The display

should alternate between “SPAN” and the current

oxygen reading (20.9 in fresh air). Pressing the Mode

button at any time cancels the span calibration.

↔

5. Screw the regulator into the cylinder and connect it to

the detector using the short section of tubing and the

calibration adapter. The regulator will automatically

begin flowing calibration gas at the correct flow rate as

soon as it is screwed into the cylinder of gas.

6. Allow the reading to stabilize. If the reading is a positive

number, use the “+” and “-“ keys to bring the value to

zero.

7. When finished, press and hold down the “Cal” key until

the display reads “DONE”.

8. Perform a fresh air zero adjustment as discussed in

section 3.6.1 when the instrument is next turned on.

Page 17

CHAPTER 4. SETTING ALARM

LEVELS

ZoneGuard alarms are user adjustable and may be set

anywhere within the range of the sensor channel. When an

alarm set point is exceeded a loud audible alarm sounds, the

appropriate LED is activated, and (if equipped) the optional

strobe light(s) and/or remote audible alarms are activated.

In addition, any other alarm devices controlled by means of

the ZoneGuard relays will also be activated.

ZoneGuard alarms are normally self resetting. When

readings drop below the alarm setpoint, the alarm ceases. It

is possible, if desired, to set ZoneGuard alarms so that they

“latch”. In the latched condition, once an alarm occurs both

visual and audible alarms continue to sound even after the

atmospheric hazard has cleared. The instrument must be

manually reset by pressing the Mode button. Pressing the

Mode button silences the alarms and restores normal

operation. Procedures for latching ZoneGuard alarms are

given in the next section.

4.1 Alarm adjustment sequence

It is necessary to be in the "Alarm Adjust" mode to change

alarm settings.

ZoneGuard default alarm settings are listed in Appendix

Note: The order of these screens may be different

depending on software version and sensor type.

Instruments equipped with a toxic or combustible gas

sensor are equipped with a low “warning” alarm and a

high “danger” alarm. Instruments equipped with an

oxygen sensor include ascending and descending low

“warning” alarms and high “danger” alarms (a total of

four alarm settings).

To enter the alarm adjust mode:

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Turn the ZoneGuard off by pressing and holding the

Mode button until the LCD goes blank. When the button

is released the LCD will display the message “OFF”.

3. With the unit turned off, press and hold down the

"Alarm" button.

4. While holding down the "Alarm" button, press the Mode

button to turn the ZoneGuard back on.

5. A screen will appear showing the first alarm point to be

adjusted, the “Low” (warning level) alarm set point. Use

the "+" and "-" keys to raise or lower the Low alarm set

point.

↔→

↔

6. Press the “Cal” button again to advance the display to

the next available alarm adjustment option, enabling or

disabling the warning level (Low) audible alarm. The

display alternates between a screen which shows the

message “AUD” and the status of the warning level

alarm, either “ON” or OFF”. Use the “+” or “-” buttons to

enable or disable this feature.

↔

7. Press the “Cal” button again to advance the display to

the next available alarm adjustment option, “latching”

the warning alarm. In the latched condition, the warning

alarms will continue to sound even after the alarm

condition has cleared. Latched alarms will continue to

sound until they are manually silenced by pressing the

Mode button. The display alternates between a screen

which shows the message “LOCK” and the status of the

alarm latch condition, either “ON” or OFF”. Use the “+”

or “-” buttons to enable or disable this feature.

↔↓

8. Press the “Cal” button again to advance the display to

the next available alarm adjustment option, the high

level (Danger) alarm setpoint. Use the “+” and “-” keys

to raise or lower the High alarm set point.

↔→

↔

9. Press “Cal” again to advance to the enable/disable

option for the Danger level alarm. Set as discussed in

Step 6.

10. Press “Cal” again to advance to the alarm latching

option for the “Danger” (high) alarm. Latching the

Danger level alarm is in the same way as latching the

warning level alarm (see step 7).

11. When all alarm adjustments have been completed,

press and hold the "Alarm" button down until an

information screen indicates that alarm adjustment is

DONE.

Caution: The “Alarm” button must be held down until

the screen indicates that alarm adjustment has been

successfully completed.

Failure to press and hold the “Alarm” button down until the

“DONE” message is displayed will cause the alarm settings

to revert to the way they were the last time the adjustment

was successfully completed.

Pressing the Mode button at any time cancels the alarm

adjustment mode, and returns the instrument to the gas

reading screen. A screen will announce “NO SAVE” after

which the instrument will turn itself off.

Page 18

↔

4.2 Restoring the factory default alarm

settings

ZoneGuard alarm settings are set conservatively at the

factory. (See Appendix C) It is possible to restore these

default settings at any time by doing the following.

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Press the "Alarm" button on the instrument key-pad.

The display will briefly show the default alarm message,

and the type of sensor currently installed.

→

3. This screen will be followed by several more showing

the specific default alarm settings. These screens will

be shown in continuous rotation. In the case of a

ZoneGuard with a hydrogen sulfide sensor installed, the

following sequence of screens would be shown.

→→

→

4. Push and hold the "Alarm" button to restore the factory

default alarm settings. The display indicates when the

settings have been restored:

5. If the Mode button is pushed, the current alarm settings

remain unchanged, and the display shows the following

screen:

↔

6. After selection of the default or current alarm settings

has been made, the display reverts to the current gas

reading screen.

4.3 Alarm Test function

ZoneGuard software includes an “Alarm Test” function that

can be used to automatically “ramp” readings throughout the

full range of the sensor. The “Alarm Test” function is used to

verify alarm setpoints as well as the proper activation of the

audible alarm, LED alarm light indicators, optional strobe

lights or horn, as well as other alarm devices or peripheral

equipment controlled by means of the ZoneGuard relay

contacts.

To use the “Alarm Test” function:

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3.

2. Simultaneously press the “Alarm” and “Cal” buttons to

begin the test. The display will show the message

screens, “ALRM TEST”, followed by numerical

readings.

→→

3. The readings shown on the ZoneGuard display will

slowly “ramp” up from zero to 10% above the high

alarm setpoint, then back down again. The audible and

visual alarms will be activated as the readings exceed

the pre-set alarm levels. (In the case of ZoneGuard

systems equipped with an oxygen sensor, readings will

both ramp up through the “ascending” warning and

danger alarms for oxygen enrichment, as well as ramp

“down” in order to test the “descending” warning and

danger alarms for oxygen deficiency.)

4. The ZoneGuard will automatically return to normal

operation when the Alarm Test function has been

completed.

5. The Alarm Test can be terminated at any time by

pressing the Mode button.

Page 19

CHAPTER 5. ADVANCED

FUNCTIONS

5.1 ZoneGuard Advanced features

overview

The ZoneGuard microprocessor circuitry makes possible a

number of advanced features and capabilities. The four

pushbuttons located on the inside of the controller housing

door are used to program advanced ZoneGuard functions.

The technique for using these buttons requires several

buttons to be pressed and held at the same time.

Caution: Do not use this technique with any other

combination of buttons than those listed below. Doing

so may result in unintended changes to the instrument

setup.

5.2 Re-setting the calibration gas

concentration

During auto calibration adjustment the ZoneGuard adjusts

the sensitivity of the sensor to match the concentration of the

gas used to calibrate the sensor. The value the instrument

uses to adjust the reading is the calibration gas

concentration stored in the instrument memory.

For instance, Biosystems normally supplies 50 ppm carbon

monoxide calibration gas for use in calibrating CO

ZoneGuard detectors. This is the default calibration gas

concentration stored in the instrument memory. When gas

is applied to the sensor during auto calibration, the

instrument automatically adjusts the calibration constants to

produce readings which match this 50 ppm concentration.

Sensor Gas used

to calibrate

sensor

True cal

gas con-

centration

Value used by

ZoneGuard to

adjust readings

Oxygen Zero Air 20.9% 20.9%

Combustible

gas Propane

Equivalent 50% LEL 50% LEL

Carbon

monoxide CO 50 ppm 50 ppm

Hydrogen

sulfide H2S 25 ppm 25 ppm

Sulfur

dioxide SO2 10 ppm 10 ppm

Chlorine Cl2 5 ppm 5 ppm

Chlorine

dioxide Cl2 5 ppm 1.7 ppm

Phosphine PH3 5 ppm 5 ppm

Nitrogen

dioxide NO2 5 ppm 5 ppm

Table 5.2. Default calibration gas concentrations used

during auto-calibration adjustment

It is necessary to re-set the calibration gas concentration

stored in instrument memory before making use of a

different calibration gas concentration.

Do not reset the calibration gas

concentration unless you are using a calibration gas

concentration which differs from that normally supplied

by Biosystems for use in calibrating your instrument.

Non-matching calibration gas and calibration gas value

settings will lead to inaccurate and potentially

dangerous readings.

Customers are strongly urged to use only Biosystems

calibration materials when calibrating their ZoneGuard

detector. Use of non-standard calibration gas and/or

calibration kit components can lead to dangerously

inaccurate readings and may void the standard

Biosystems warranty.

Use the following procedure to re-set the calibration gas

concentration:

1. Make sure gas readings are given in numbers. If the

display shows “OK”, then the ZoneGuard is currently

being operated in the “Text Only” mode. To change

over to Basic mode, simultaneously hold down the "+"

and"-" keys as discussed in section 2.9.3. 2. Turn the

instrument off by pressing the Mode button until the

display blanks.

3. While holding down the “+” button, press the Mode

button to turn the ZoneGuard back on.

4. The ZoneGuard LCD will display alternating “CAL” and

“GAS” messages for 4 seconds. The display will then

alternate between the current concentration stored in

memory and the “GAS” message screens.

5. Use the “+” and “-” buttons to change the concentration.

6. Once the proper new concentration has been selected,

press and hold down the “Alarm” button for three

seconds. Do not release the “Alarm” button until the

LCD displays the message “DONE” to indicate that the

new value has been successfully entered.

7. Pressing the Mode button at any time cancels the

procedure. The LCD will show the message “NO

SAVE” to indicate that the calibration gas concentration

values have not been changed.

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