Sensidyne SensAir User manual

Toxic Gas Detector
User Manual
Document No. 360-0194-02 Rev H
Sensidyne, LP • 1000 112th Circle N, Suite 100
St. Petersburg, Florida 33716 USA
800-451-9444 • [phone] • [phone] [fax]
web: www.sensidyne.com • e-mail: [e-mail]

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 3
How to Use This Manual
This manual is a guide for using the SensAir Toxic Detector. It contains information on the detector, detector
components, and the Normal Operation Display. It also shows how to mount and wire the detector, initial setup,
zeroing, and span calibration. In addition, it covers commonly used operations regarding alarms and relays. For
reference, the entire menu structure is outlined in Appendix- Menu Map
Because the SensAir Toxic Detector is menu driven, it is important to become familiar with how the magnetic
switch controls are used to navigate through the menus, select specific menu items, and change the many
different parameters available to the user. The Menu Map in the Appendix will help you toward this end.

SensAir Toxic Gas Detector
4 Sensidyne Document No. 360-0194-02 (Rev H)
Table of Contents
How to Use This Manual................................................................................................................................ 3
Packing List and Notices................................................................................................................................ 7
WARNINGS ................................................................................................................................................. 8
1INTRODUCTION.........................................................................................................10
2SENSAIR PART NUMBER SYSTEM..........................................................................11
3COMPONENTS...........................................................................................................12
3.1 Condulet Housing............................................................................................................................... 12
3.2 Display................................................................................................................................................ 12
3.2.1 Electronics...................................................................................................................................14
3.3 The Sensor Assembly......................................................................................................................... 14
4INSTALLATION ..........................................................................................................15
4.1 Location .............................................................................................................................................. 15
4.2 Detector Installation (Enclosure)......................................................................................................... 15
4.3 Detector Location................................................................................................................................ 16
4.3.1 Wiring..........................................................................................................................................16
4.3.1.1 Detector Wiring Diagram...................................................................................................................... 16
4.3.2 Allowable Line Length.................................................................................................................17
4.3.3 Wiring Procedure ........................................................................................................................18
5OPERATION ...............................................................................................................19
5.1 Output Current.................................................................................................................................... 19
5.2 Interferents.......................................................................................................................................... 19
6START UP PROCEDURE...........................................................................................20
7CALIBRATION............................................................................................................21
7.1 Equipment........................................................................................................................................... 21
7.2 Zeroing................................................................................................................................................ 21
7.3 Select Calibration Gas Concentration ................................................................................................ 21
7.4 Calibration Procedure......................................................................................................................... 22
8MAINTENANCE..........................................................................................................23
8.1 Sensor replacement:........................................................................................................................... 23

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 5
8.2 Sensor Assembly Replacement ..........................................................................................................23
9 APPENDIX- MENU MAP ................................................................................................25
10 APPENDIX- FAULT CODES.......................................................................................29
11 APPENDIX- DIMENSIONAL DRAWINGS ..................................................................30
11.1 Dimensions..........................................................................................................................................30
12 APPENDIX- CALIBRATION EQUIPMENT .................................................................32
Calibration Gases .......................................................................................................................................32
13 APPENDIX –ACCESSORIES AND SPARES............................................................34
14 APPENDIX- SPECIFICATIONS..................................................................................35
15 SENSOR DATA SHEETS ...........................................................................................36
15.1 Hydrogen Sulfide, H2S, 50ppm............................................................................................................36
15.2 Hydrogen Sulfide, H2S, 100ppm..........................................................................................................37
15.3 Ammonia, NH3, 50ppm........................................................................................................................38
15.4 Ammonia, NH3, 100ppm......................................................................................................................39
15.5 Ammonia, NH3, 300ppm......................................................................................................................40
15.6 Carbon Monoxide, CO, 500ppm..........................................................................................................41
15.7 Carbon Monoxide, CO, 100ppm..........................................................................................................42
15.8Chlorine, Cl2, 5.0ppm...........................................................................................................................43
15.9 Chlorine, Cl2, 10.0ppm.........................................................................................................................44
15.10Hydrogen Chloride, HCl, 10.0ppm.......................................................................................................45
15.11Hydrogen Chloride, HCl, 100ppm........................................................................................................46
15.12Nitrogen Dioxide, NO2, 10ppm............................................................................................................47
15.13Hydrogen, H2, 1000ppm......................................................................................................................48
15.14Hydrogen Cyanide, HCN, 20.0ppm.....................................................................................................49
15.15Hydrogen Fluoride, HF, 10.0ppm........................................................................................................50
15.16Sulfur Dioxide (Filtered), SO2, 20.0ppm..............................................................................................51
15.17Chlorine, ClO2, 5.00ppm......................................................................................................................52
16 APPENDIX- ALLOWABLE LINE LENGTHS..............................................................53

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6 Sensidyne Document No. 360-0194-02 (Rev H)
17 SENSAIR MODBUS RELAY OPTION BOARD..........................................................54
18 SENSAIR MODBUS REGISTER ADDRESSES (OPTION) ........................................59
19 SENSAIR MODBUS SPECIFICATIONS (OPTION)....................................................60
20 WIRING RELAYS (OPTIONAL)..................................................................................61
21 APPENDIX- TROUBLESHOOTING GUIDE................................................................62
22 RETURNEDMATERIALAUTHORIZATION......................................................................63

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 7
Packing List and Notices
You should have the following items:
SensAir Toxic Gas Detector unit
Magnetic Screwdriver
User Manual (this document)
Always check to make certain you have received all of the items listed above. If you have any questions or need
assistance, contact your Sensidyne Representative, or call 800-451-9444 or [phone]
PROPRIETARY NOTICE
This manual was prepared by Sensidyne, LP exclusively for the owner of the SensAir Toxic Gas Detector. The
material within this manual is the proprietary information of Sensidyne, LP and is to be used only to understand
and operate the instrument. By receiving this document, the recipient agrees that neither this document nor the
information disclosed within nor any part shall be reproduced or transferred, physically, electronically or in any
form or used or disclosed to others for manufacturing or for any other purpose except as specifically authorized in
writing by Sensidyne, LP.
COPYRIGHT NOTICE
©2014, Sensidyne, LP All rights reserved. Information contained in this document is protected by copyright. No
part of this document may be photocopied, reproduced, or translated to another program or system without prior
written authorization from Sensidyne, LP
TRADEMARK NOTICE
Sensidyne, the Sensidyne logo, SensAlert, the SensAlert & SensAir logos, T-O-D & Test-on-Demand are
registered trademarks of Sensidyne, LP. The trademarks and service marks of Sensidyne, LP are protected
through use and registration in the United States of America.
SOFTWARE LICENSE
The software included with the SensAir Toxic Detector is the property of Sensidyne, LP and shall remain the
property of Sensidyne, LP in perpetuity. The software is protected by U.S. and international copyright laws and is
licensed for specific use with the SensAir Toxic Gas Detector. The user may not reverse-engineer, disassemble,
decompile, or make any attempt to discover the source code of the software. The software may not be translated,
copied, merged or modified in any way. The user may not sublicense, rent, or lease any portion of the software.
The right to use the software terminates automatically if any part of this license is violated.
DISCLAIMER
SENSIDYNE, LP ASSUMES NO RESPONSIBILITY WHATSOEVER, TO ANY PARTY WHOSOEVER, FOR ANY
PROPERTY DAMAGE, PERSONAL INJURY, OR DEATH CAUSED BY OR RESULTING FROM, IN WHOLE, OR
IN PART, THE IMPROPER USE, INSTALLATION, OR STORAGE OF THIS PRODUCT BY THE USER,
PERSON, FIRM, ENTITY, CORPORATION OR PARTY NOT ADHERING TO THE INSTRUCTIONS AND
WARNINGS OR NOT ADHERING TO ALL FEDERAL, STATE, AND LOCAL ENVIRONMENTAL AND
OCCUPATIONAL HEALTH AND SAFETY LAWS AND REGULATIONS.
THE SELLER SHALL NOT BE LIABLE FOR DIRECT, INDIRECT, CONSEQUENTIAL, INCIDENTAL OR OTHER
DAMAGES RESULTING FROM THE SALE AND USE OF ANY GOODS AND SELLER’S LIABILITY
HEREUNDER SHALL BE LIMITED TO REPAIR OR REPLACEMENT OF ANY GOODS FOUND DEFECTIVE.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR USE OR FOR A
PARTICULAR PURPOSE WHICH ARE EXPRESSLY DISCLAIMED.

SensAir Toxic Gas Detector
8 Sensidyne Document No. 360-0194-02 (Rev H)
WARNINGS
READ AND UNDERSTAND ALL WARNINGS BEFORE USE
Read and understand ALL warnings before using this product. Failure to read, understand, and comply
with ALL warnings could result in property damage, severe personal injury, or death.
Product is calibrated prior to shipment, however, this product must be calibrated prior to initial use. Calibrate at
regular intervals in accordance with the User Manual. Failure to calibrate in accordance with the instructions in
this manual and at the specified intervals may result in the product not operating properly or malfunctioning.
Read and understand ALL applicable federal, state, and local environmental health and safety laws and
regulations, including OSHA. Ensure complete compliance with ALL applicable laws and regulations before and
during use of this product.
The user/installer must understand the Hazardous Area Protection Concepts and Area Classifications applicable
to their operation.
UNDER NO CIRCUMSTANCES should this product be used except by qualified, trained, technically competent
personnel and not until the warnings, User Manual, labels, and other literature accompanying this product have
been read and understood.
Failure to read and understand the User Manual may result in preventable severe personal injury or death.
ALWAYS wash your hands thoroughly after handling, calibrating, or servicing this product.
ALWAYS wear eye protection (such as safety goggles), face shield, chemical resistant gloves and chemical
resistant clothing when handling chemicals, or calibration sources.
DO NOT get chemicals, gases, fumes, or vapors in your eyes or on your skin, as they may cause severe burns to
skin and eyes. If chemicals, gases, fumes, or vapors get in your eyes or on your skin, wash the affected area with
copious amounts of water and call a physician immediately.
ALWAYS avoid any contact of acids with your skin or eyes. Seek immediate medical attention for any contact with
acids.
ALWAYS calibrate in a well-ventilated area. Adequate precautions should be taken to prevent the buildup of ANY
calibration sources or vapors. Avoid breathing ANY calibration fumes or vapors as they may be hazardous to your
health.
ALWAYS dispose of chemicals and calibration sources in compliance with ALL applicable safety laws,
regulations, and guidelines for proper disposal. Failure to do so may result in environmental damage, property
damage, personal injury or death.
ALWAYS close ALL containers of chemicals used with this product after use.
ALWAYS ensure that any compressed calibration substance sources are empty prior to disposal, should they be
used.
ALWAYS use clean, dry, inert materials to contain and transfer substances used for calibration.
DO NOT remove, cover, or alter any label or tag on this product, its accessories, or related products.
DO NOT operate this product should it malfunction or require repair. Operation of a malfunctioning product, or a
product requiring repair may result in serious personal injury or death.
DO NOT attempt to repair or modify instrument, except as specified in the Operation & Service Manual. If repair is
needed, contact the Sensidyne Service Dept. to arrange for a Returned Material Authorization (RMA) Returned
Material Authorization
Users should refer to MSDS and suppliers’ instructions for proper handling and safety instructions for any
chemicals used with this equipment.

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 9
WARNINGS
READ AND UNDERSTAND ALL WARNINGS BEFORE USE
Use ONLY genuine SENSIDYNE® replacement parts when performing any maintenance procedures described in
this manual. Failure to do so may seriously impair instrument performance and affect Certification. Repair or
alteration of the product beyond the scope of these maintenance instructions, or by anyone other than an
authorized SENSIDYNE® service technician, could cause the product to fail to perform as designed and persons
who rely on this product for their safety could sustain severe personal injury or death.
The product is intended for non-hazardous locations and is not intended as a life safety device. It is intended to
detect gas and act as a warning signal for the protection of personnel or building structures.
The SensAir Toxic Gas Detector is an ambient air monitoring device. Restricting the access of ambient air to the
sensor may result in less than optimal monitoring performance.
Prolonged exposure to excessively high concentrations of gas may cause the sensor to produce erroneous
readings.
Always make use of a rainshield to protect against variations caused by environmental conditions.
Perform tests only within the specified operating ranges.
Sudden changes in pressure may cause temporary fluctuations in the sensor reading.
Important Calibration Considerations:
Unit calibration must be done at altitude.
Verify concentration of calibration gas before making calibration adjustments.
Concentration can be altered by:
Deterioration of the concentration of compressed calibration gas sources during storage.
Interaction of the calibration gas with materials used to contain and transfer the gas, as for example,
absorption onto and permeation through certain plastics.
Interaction of the calibration gas with materials and/or ambient contaminants, as for example, absorption into
water.
If further translation is required, please contact the Sensidyne EU Authorized Representative (see Back Cover for
contact information).

SensAir Toxic Gas Detector
10 Sensidyne Document No. 360-0194-02 (Rev H)
1INTRODUCTION
This manual provides specific information concerning the installation, operation, calibration, and maintenance of
the SensAir Toxic Gas Detector.
IMPORTANT: Owners of the Toxic Gas Detector must read this manual in its entirety in order to ensure proper
operation of the detector.
The SensAir Toxic Gas Detector is non-hazardous, single-point device capable of detecting the presence of
various substances. The detector detects each substance in ppm levels.
The standard detector consists of a display board and a power supply board housed in a heavy duty enclosure, a
sensor specifically designed to detect Toxic substances, and optionally, a relay/Modbus board.
A complete monitoring system consists of the detector and a separate read-out device & Class 2 power supply
capable of monitoring a 4-20 mA output and supplying 12-30 Vdc power.
Product specifications are located in Appendix B.
Different versions of the detector are available (see Part Number Table). The selection of the version best suited
to an application depends upon the application requirement.
PVC and Anodized aluminum are for general purpose and heavy duty industrial applications.

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 11
2SensAir Part Number System
SensAir Toxic/Oxygen Transmitters
8 2 0 -
□
□
□
□
-□
□
□
□
- R
| |
| | | | | |
↓ ↓
| | | | | |
0 8 DIV 1
| | | | | |
0 9 DIV 2
| | | | | |
1 0 GP
| | | | | |
1 1 GP Plastic ↓ ↓
| | | |
0 1 Oxygen (O2)
| | | |
0 2 Hydrogen Sulfide (H2S) 50ppm
| | | |
0 3 Hydrogen Sulfide (H2S) 100ppm
| | | |
0 4 Ammonia (NH3) 50ppm
| | | |
0 5 Ammonia (NH3) 100ppm
| | | |
0 6 Ammonia (NH3) 300ppm
| | | |
0 7 Carbon Monoxide (CO) 100ppm
| | | |
0 8 Carbon Monoxide (CO) 500ppm
| | | |
0 9 Carbon Monoxide (CO) 1000ppm
| | | |
1 0 Chlorine (Cl2) 5ppm
| | | |
1 1 Clorine (Cl2) 10 ppm
| | | |
1 2 Hydrogen Chloride (HCl) 10ppm
| | | |
1 3 Hydrogen Chloride (HCl) 100ppm
| | | |
1 4 Nitrogen Dioxide (NO2) 10ppm
| | | |
1 5 Hydrogen (H2) 1000ppm
| | | |
1 6 Hydrogen Cyanide (HCN) 20ppm
| | | |
1 7 Hydrogen Fluoride (HF) 10ppm
| | | |
1 8 Sulfur Dioxide (SO2) 20ppm
| | | |
1 9 Chlorine Dioxide (ClO2) 5ppm ↓|
| |
1 Display |
| |
2 No Display ↓
|↓
0 No Options
| |
1 MODBUS/Relay
|↓
2 BacNet
| |
3 Other ↓ ↓
1 Horizontal |
2 Vertical ↓
1 Stainless Steel Sensor Holder w/Mesh
2 Stainless Steel Sensor Holder w/Disk
3 Aluminum Sensor Holder w/Disk
4 Aluminum Sensor Holder w/ Poly Screen
5 Gray PVC Sensor Holder w/ Poly Screen

SensAir Toxic Gas Detector
12 Sensidyne Document No. 360-0194-02 (Rev H)
3Components
3.1 Condulet Housing
The condulet housing is a heavy duty weather-resistant barrier between the electronics module and the ambient
environment. The housing is available with a window for the display of the detector or without the window (in the
aluminum enclosure).
An o-ring on the condulet seated between the condulet cover and the base provides water-tight protection for the
internal electronic components. It allows the detector to be used outdoors during inclement weather conditions.
3.2 Display
The detector with display has Program and Up and Down selector magnetic switches. These are controlled via
the magnetic screwdriver provided with the unit. Information on operating the various controls is located in the
Appendix Menu Map.
The display shows the following:
(1) Gas Concentration
The gas concentration is displayed in large characters; units of measure are ppm or %volume.
(2) PROGRAM Control (Switch)
The Program switch is used to enter the programming menu. The switch is also used to select/save a menu
item.
(3) ▲and ▼
The ▲ and ▼ control arrows are used to scroll up or down a list of items. These controls are also used to
increase or decrease a value (such as an alarm setpoint).
Holding the wand near the control (switch) causes the displayed value to either increase or decrease
automatically.
(4) LEDs
The detector display has LEDs that light up when there is an alarm or fault condition occurring.
Also, when the magnetic wand is brought close to a magnetic switch the LED associated with that switch lights
up, confirming that contact has been made between the wand and the switch.
The detector without display requires the use the Hand Held Display to program and calibrate the unit. The Hand
Held Display unit is sold separately. Part number for the Hand Held Display is 821-0602-01-R.
This detector is for unclassified areas, however, prior to using the Hand Held Display,
confirm the area is free of hazardous gases.
Please confirm the area is free of hazardous conditions prior to opening the enclosure on the SensAir Toxic
detector. The unit is designed for non-hazardous areas, so hazardous gases should not be present.
The hand held display connects to the main board in the detector. Caution should be taken when plugging the
display connector to the board. The connector is keyed and only installs one way. Once attached, it functions the
same as the detector with display.

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 13
Connection
Port for
Hand Held
Display unit
Connection is
Keyed.

SensAir Toxic Gas Detector
14 Sensidyne Document No. 360-0194-02 (Rev H)
3.2.1 Electronics
The electronics inside the condulet consist of a display board (if installed), a power supply board and optional
relay board. They are housed within the condulet, and converts the sensor response into a 4-20 mA current,
linearly proportional to the concentration of the Toxic gas present at the sensor.
3.3 The Sensor Assembly
CAUTION: DO NOT attempt to install the sensor assembly into any detector other
than the designated SensAir Toxic Gas Detector.
The sensor assembly consists of an electrochemical sensor.
Toxic sensors are electrochemical sensors designed to respond to the presence of a specific gas. Gas molecules
permeate the sensor membrane and initiate an electrochemical reaction in the sensor. The sensor assembly
consists of sealed sensor attached to a circuit board. A female connector mounted on top of the circuit
board mates with a male connector mounted inside the sensor interface assembly.
WARNING: The Toxic sensor CANNOT be used to monitor for combustible hazards.

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 15
4Installation
4.1 Location
The Toxic Gas Detector is a local area monitor. It is imperative that the detector be located in an area where the
greatest concentration of the target gas will be present in the shortest period of time after the occurrence of a leak
or other increase in the concentration of the target gas in the atmosphere. Expert consultation may be necessary
to determine the most strategic location for optimum monitoring. In all circumstances, the plant safety officer or
other appropriate personnel should be consulted before installation.
Site determination, at a minimum, must consider the following factors:
•most probable location of a leak
•physical properties of the target gas
•air convection in the area due to ventilation or ambient conditions
•operational environment
•presence of interferent gases
Ultimately, monitoring efficiency, and the degree of protection it affords, depends upon how carefully this survey is
made.
4.2 Detector Installation (Enclosure)
Refer to all local electrical codes to ensure compliance for proper mounting.
The detector mounts to a wiring conduit via (19 mm) 3/4” female NPT at the condulet. To achieve a measure of
RFI/EMI immunity, the enclosure and conduit must be grounded and shielded cable must be used.
The detector should be mounted with the sensor facing down to prevent moisture and debris from collecting on
the sensor itself.
1) Get confirmation from the safety officer that the area is free of hazardous atmospheres. This detector is
intended for general purpose areas so hazardous gases should not be present.
2) For the Blue Metal enclosure: Unscrew and remove the condulet cover. For the Plastic Square enclosure:
Remove the four corner screws to remove the cover.
3) Confirm that the input and output wires are without power and thread them through the opening of the
housing.
4) Hold the wires out of the way and screw the condulet firmly into the conduit.
5) Cap the wires and replace the detector cover. For the Plastic Square enclosure, secure all four corner
screws that were removed if you are not going to wire the detector at this time.

SensAir Toxic Gas Detector
16 Sensidyne Document No. 360-0194-02 (Rev H)
4.3 Detector Location
4.3.1 Wiring
Refer to all local electrical codes to ensure proper wiring compliance. The use of shielded wire is recommended.
NOTE
The power supply must have a power source return isolated from earth ground. A Class 2 power supply must be
used. Shielded cable is recommended with shield terminated to earth ground to ensure a measure of RFI/EMI
immunity. If the metal conduit to which the detector is mounted is not earth grounded, the condulet must be earth
grounded via the green wire.
The following sections provide specific information necessary to wire the detector to a Class 2 power supply. A
wiring diagram is provided to aid in wiring the detector to a power supply.
Three (3) wires are required to connect the detector to a Sensidyne controller, or a customer supplied 12-
30 Vdc Class 2 power supply and read-out device. See Figure 4.3.1 for wiring.
Bottom of Main PCA board showing Black, White and Red Wire connected.
4.3.1.1 Detector Wiring Diagram
NOTE
Installation and wiring must be in accordance with National Electrical Code. Temperature rating of cable wire
insulation must be specified to be above 75 C (167 F). If cable runs through temperatures which exceed 75 C, it
should be specified for that environment.
3-Wire Powered Unit
Power
V+
Red
4-20 Output
4-20 mA
White
Ground
RTN
Black

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 17
FIGURE
4.3.1
DETECTOR WIRING
4.3.2 Allowable Line Length
The maximum distance between the Class 2 power supply and the detector is known as the allowable line length.
It is a function of the power supply voltage, loop resistance, and termination resistance. This in turn determines
allowable loop resistance and wire size.
Please refer to the table in the Appendix for the allowable line lengths for various wire sizes as well as the
allowable loop resistance for various power supply voltages. The allowable voltage range for the power supply is
12-30 Vdc.

SensAir Toxic Gas Detector
18 Sensidyne Document No. 360-0194-02 (Rev H)
4.3.3 Wiring Procedure
The detector terminals will not accept wire gauges larger than 14 AWG. 18 AWG is recommended as it is less
rigid. In all cases, the connections must be clean, tight and protected from the weather. They must meet all
required electrical codes. Remove factory supplied test wires. In order to maintain RF immunity move all ferrites
from test wires to user supplied wiring.
Wire the detector as follows:
1) Get confirmation from the safety officer, or appropriate personnel, that the area is safe.
2) Verify that the conduit and the detector are securely connected together.
3) Verify that the input and output wires are (without power).
4) Unscrew and remove the condulet cover on the blue metal enclosure, or on the square plastic enclosure,
remove the four corner screws to pull off the cover.
5) Verify that the total resistance of the wiring does not exceed the allowable loop resistance
6) Attach and secure the power source return (negative lead) wire to the “RTN” Terminal (3) on the J1
connector.
7) Attach and secure the 4-20 mA output wire to the “4–20 mA” Terminal (2) on the J1 connector.
8) Attach and secure the positive lead wire to the “V+” Terminal (1) on the J1 connector.
9) Replace the condulet cover if not proceeding with start-up at this time.
10) Before applying power to the detector, verify that all connections are correct.
11) Go to Start-Up Section when you are ready to perform the start-up procedure.

SensAir Toxic Gas Detector
Sensidyne Document No. 360- 0194-02 (Rev H) 19
5Operation
NOTE: The detector must be calibrated after initial installation and before normal operation is possible.
(See Calibration Section)
All Sensidyne gas detection equipment is functionally tested and calibrated with known zero and span gases
before shipment to the customer. However, it is recommended that qualified personnel verify operation after initial
installation using known zero and span gases. Repeat verification at 30 days and 60 days after initial installation,
with deviations in zero and span recorded. The calibration or functional check interval can then be adjusted to suit
that application’s conditions. For further information, please consult the ISA Recommended Practices for gas
detectors.
Under normal operating conditions, the detector responds to the presence of Toxic gas by producing a 4-20 mA
current that is linearly proportional to the concentration of Toxic gas present at the sensor.
5.1 Output Current
When calibrated, the relationship between the output current of the detector (in mA) and the concentration of the
target gas is linear. Concentration is shown as a Percentage of Full Scale.
5.2 Interferents
Although highly selective for a particular gas, a sensor is not always completely specific. Certain sensor
types will also respond to another gas, particularly if the other gas has similar physical/chemical
properties. This “other” gas is called an interferent. Every effort is made to identify and minimize these
interferences.
NOTE
The Interferent Tables are intended for guidance only. For the most accurate measurements the monitor should
be calibrated using the target gas under investigation.

SensAir Toxic Gas Detector
20 Sensidyne Document No. 360-0194-02 (Rev H)
6Start Up Procedure
It is necessary to perform the following start up procedure upon initial installation. Performance of the startup
procedure is not ordinarily required at the time of routine periodic calibration. However, the startup procedure
should be performed when any of the following occurs:
• loss of power for an extended period time
•upon sensor assembly replacement
•following a flooded response
WARNING: The safety officer must ensure that the area is safe
before the condulet may be opened.
1) Unscrew and remove the condulet cover.
2) Make certain the detector has been wired properly.
3) Apply power to the detector. Observe that the Display has proper indications. If the Display does not
have proper indication go to Appendix Troubleshooting Guide to determine the cause of the problem.
CAUTION: Do not continue with the start-up procedure until this problem has been corrected.
4) Allow the detector to warm up.
5) Replace the condulet cover. Allow the unit to stabilize for at least 1 hour before calibrating the detector
6) The Toxic Gas Detector must be calibrated prior to initial use and at regular intervals thereafter. In
addition, the calibration procedure must be performed if any of the following conditions occur:
• loss of power for an extended period of time
• detector is overranged or flooded
• sensor assembly is replaced
Failure to maintain this schedule could result in impaired system performance and/or erroneous readings.
NOTE
If calibration is being performed prior to initial use or after sensor replacement, thedetector must be allowed
to stabilize with power applied for 1 hour before attempting the calibration procedure.
All Sensidyne gas detection equipment is functionally tested and calibrated with known zero and span gases before
shipment to the customer.
However, it is recommended that qualified personnel verify operation after initial installation using known zero and
span gases.
For further information, please consult the ISA Recommended Practices for gas detectors.
NS T ALL A ION