Sensidyne SensAlarm Plus User manual

Universal Gas Monitoring System
User Manual
Document No. 360-0126-01
(Revision D)
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: [email protected]

SensAlarm Plus – Universal Gas Monitoring System User Manual
Page 2 Document No. 360-0126-01 (Rev. D)
How to Use This Manual
This manual is a basic guide for using the SensAlarm Plus Universal Gas Monitoring System. It contains
information on SensAlarm Plus components, sensor types, and the Normal Operation Display. It also shows
how to mount and wire the Monitor, initial setup, zero, and span calibration. In addition, it covers commonly
used operations regarding alarms, relays, and Test-On-Demand.
Important notes, cautions, and warnings are set off from the other text as follows:
NOTE
This is an important note
MENU MAP and MENU FUNCTIONS
The entire menu structure is outlined in Section 5.2, Menu Structure, with descriptions of each function in
Section 3, Operating Functions and Section 4, Alarms and Relays.
The SensAlarm Plus Gas Monitor is menu driven, so is important to become familiar with how the four 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 Basic Menu Controls Guide is below.
Basic Menu Controls Guide
Selecting OK from the Normal Operation Display enters the SensAlarm Plus menu system. Within the menu
system OK is to 1) to select an item from a list of menu items, 2) to confirm that an action has occurred (e.g.
changing an alarm from “Non-Latching” to “Latching”), or 3) to save a new value that has been entered (e.g., a
netion for configded. It is similar in use to an ESC key on a computer keyboard.
The Ÿcontrol arrow is used to move UP a list of menu items.
The źcontrol arrow is used to move DOWN a list of menu items.
The Ÿand źcontrol arrows also are used to increase/decrease numeric values of certain menu items (e.g.
alarm Setpoint, cal gas concentration, etc.).
PLEASE NOTE
This manual contains illustrations of those display screen menu options generally used in the normal course of
operation of the SensAlarm Plus Monitor. The Monitor may also display a variety of additional warning or
cautionary screens. These additional display screens are instructive and self-explanatory in nature. The user
should read each display screen and perform the recommended actions as required.
Important
Factory Default Settings
Each Monitor is shipped from the factory with default settings. These include default settings for alarms,
warnings and relays. The default settings can be found in Section 12 – Appendix G: Configuration
Reference (page 113). Please note that boxes filled with an “X” indicate a default setting for that particular
alarm, warning, or relay. Additional blank copies of the Configuration Reference form can be found in Section
12. These blank forms are intended for use by the user to document user-defined changes from the factory
default settings.

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 3
Table of Contents
How to Use This Manual.................................................................................................................................2
Basic Menu Controls Guide............................................................................................................................2
Packing List and Notices.................................................................................................................................7
WARNINGS....................................................................................................................................................8
1 INTRODUCTION .........................................................................................................10
1.1 Product Versions.................................................................................................................................10
1.2 Standard Features...............................................................................................................................11
1.2.1 Universal Sensor Capability........................................................................................................11
1.2.2 Large Displays for Ease of Operation.........................................................................................11
1.2.3 Non Intrusive Operation..............................................................................................................11
1.2.4 Transportable Calibration ...........................................................................................................11
1.2.5 Predictive Failure........................................................................................................................11
1.2.6 AC & External DC Power Capability...........................................................................................11
1.3 Factory Installed Options.....................................................................................................................12
1.3.1 Test-On-Demand™ Gas Generator............................................................................................12
1.3.2 Remote Sensor Operation..........................................................................................................12
1.3.3 Communication Options .............................................................................................................12
1.3.4 Dual Strobes...............................................................................................................................12
1.3.5 Internal 30 Minute Battery Backup..............................................................................................12
1.4 SensAlarm Plus Components .............................................................................................................13
1.4.1 Sensor Interface Assembly.........................................................................................................13
1.4.2 SensAlert Plus Sensor................................................................................................................13
1.4.3 Test-on-Demand™ .....................................................................................................................13
1.4.4 Sensor Holder.............................................................................................................................13
1.4.5 Rainshield...................................................................................................................................13
1.4.6 Calibration Plug Assembly..........................................................................................................13
1.4.7 Liquid Crystal Display and Magnetic Controls............................................................................15
1.4.8 Sensor Types..............................................................................................................................16
1.4.9 SensAlarm Plus Housing............................................................................................................17
1.4.10 SensAlarm Plus Power Available LED (3)..................................................................................17
1.4.11 Red Strobe..................................................................................................................................17
1.4.12 Amber Strobe (option) ................................................................................................................18
1.4.13 Sounder ......................................................................................................................................18
A 95dB Piezo horn is located on the bottom right side of the enclosure. The sounder activates during
alarm and warning conditions. The sounder can be silenced with a red pushbutton switch. The alarm reset
conforms to ISA alarm sequence 3A.........................................................................................................18
1.4.14 Reset Button...............................................................................................................................18
1.5 Electronics Modules ............................................................................................................................19
1.5.1 Display PCA................................................................................................................................20
1.5.2 LED display (4-digit) PCA...........................................................................................................20
1.5.3 Power Assembly TB1, TB2.........................................................................................................20
1.5.4 Barrier PCA.................................................................................................................................21
1.5.5 AC Power supply ........................................................................................................................21
1.5.6 Main PCA....................................................................................................................................21
2 INSTALLATION...........................................................................................................22
2.1 Location...............................................................................................................................................22

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2.2 Fire or other Code Compliance Issues and annunciation requirements.............................................22
2.3 Monitor Installation..............................................................................................................................22
2.3.1 AC Power....................................................................................................................................24
2.3.2 DC Power ...................................................................................................................................25
2.3.3 Wiring Procedure (4-20 mA Output)...........................................................................................25
2.3.4 Wiring Procedure (Relay Outputs) .............................................................................................25
2.4 Start Up...............................................................................................................................................26
3 OPERATING FUNCTIONS..........................................................................................27
3.1 Calibration...........................................................................................................................................27
3.1.1 Zeroing the Monitor ....................................................................................................................28
3.1.2 Span Calibration.........................................................................................................................29
3.2 Sensor Adjustment..............................................................................................................................33
3.2.1 Select Calibration Gas................................................................................................................34
3.2.2 Selecting a K-Factor...................................................................................................................35
3.2.3 Selecting a Custom K-Factor......................................................................................................37
3.3 ToD Mode Adjustment ........................................................................................................................38
3.3.1 Auto Mode, Enable/Disable........................................................................................................39
3.3.2 ToD Auto Mode, Test Date/Time................................................................................................40
3.3.3 ToD Auto Mode, Days Between Tests.......................................................................................40
3.3.4 ToD Mode Adjustment, Cell Intensity.........................................................................................41
3.3.5 ToD Mode Adjustment, Output Indicators..................................................................................42
4 ALARMS, FAULTS AND RELAYS.............................................................................43
4.1 Alarms.................................................................................................................................................44
4.1.1 Add a Relay................................................................................................................................45
4.1.2 Delete a Relay............................................................................................................................46
4.1.3 Enable or Disable an Alarm........................................................................................................46
4.1.4 Ascending or Descending alarm threshold.................................................................................47
4.1.5 Alarm Setpoint............................................................................................................................47
4.1.6 Release Offset............................................................................................................................48
4.1.7 TWA Average Time Adjustment.................................................................................................48
4.2 Fault Functions....................................................................................................................................49
4.2.1 Add a Relay................................................................................................................................50
4.2.2 Delete a Relay............................................................................................................................50
4.2.3 Enable or Disable a Fault...........................................................................................................51
4.2.4 Adjust Fault Current....................................................................................................................51
4.2.5 Adjust Fault Current Delay .........................................................................................................51
4.3 Warn Current – Relay 5 .....................................................................................................................52
4.3.1 Warn Current-Relay 5, Latching/Non-Latching ..........................................................................52
4.3.2 Warn Current – Relay 5, Enable or Disable...............................................................................53
4.3.3 Low Current Time Adjust............................................................................................................53
4.4 Relay 1-Fail, Relay 2, Relay 3, Relay 4 ..............................................................................................54
4.4.1 Latching or Non-Latching ...........................................................................................................54
4.4.2 Norm Energized/ Norm De-Energized........................................................................................54
4.4.3 Time Delay..................................................................................................................................55
4.5 Horn – Relay 6 ...................................................................................................................................56
4.5.1 Latching or Non-Latching ...........................................................................................................56
4.5.2 Timeout (Enabled/Disabled).......................................................................................................56
4.5.3 Time Delay..................................................................................................................................57
4.5.4 Timeout Delay.............................................................................................................................57

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 5
4.6 Red Strobe - Relay7, Amber Strobe-Relay8.......................................................................................58
4.6.1 Latching or Non-Latching............................................................................................................58
4.6.2 Norm Energized/ Norm De-Energized........................................................................................59
4.6.3 Time Delay..................................................................................................................................59
5 MENU STRUCTURE & MAP.......................................................................................60
Basic Guide to Using the Menu System.......................................................................................................60
SENSALARM
PLUS
Menu Structure................................................................................................................60
5.1 Main Menu Screen ..............................................................................................................................60
5.2 Main Menu (screens)...........................................................................................................................87
As shown on the example display to the right, the top level (main) menu allows the selection of several
submenus, documented below. Selecting OK brings up the submenus...................................................87
5.2.1 Calibration Mode........................................................................................................................87
5.2.1.1 Zero Monitor......................................................................................................................................... 87
5.2.1.2 Calibrate............................................................................................................................................... 87
5.2.1.3 Set Cal Gas Concentration................................................................................................................... 88
5.2.2 Maintenance Mode .....................................................................................................................88
5.2.3 Data Review................................................................................................................................88
5.2.3.1 Calibration Info..................................................................................................................................... 89
5.2.3.2 Sensor Status....................................................................................................................................... 89
5.2.3.3 Sensor Data ......................................................................................................................................... 89
5.2.3.4 Active Alarms/Faults............................................................................................................................. 89
5.2.3.5 Fault Currents....................................................................................................................................... 90
5.2.3.6 Fault Current Delay.............................................................................................................................. 90
5.2.3.7 Rly Alm Fault Config............................................................................................................................. 90
5.2.3.8 ToD Review.......................................................................................................................................... 91
5.2.3.9 Communication Review........................................................................................................................ 91
5.2.3.10 Firmware Review.................................................................................................................................. 91
5.2.4 Test-On-Demand (Main Menu)...................................................................................................92
5.2.5 System Configuration .................................................................................................................92
5.2.5.1 Self Test92
5.2.5.2 Alarm Settings...................................................................................................................................... 93
5.2.5.3 4/20 mA Adjustment............................................................................................................................. 98
5.2.5.4 Adjust Date/Time.................................................................................................................................. 99
5.2.5.5 Communication Setup.......................................................................................................................... 99
5.2.5.6 ToD Mode Adjustment........................................................................................................................ 100
5.2.5.7 Sensor Adjustment............................................................................................................................. 100
5.2.5.8 Set Password..................................................................................................................................... 101
5.2.5.9 Reset Defaults.................................................................................................................................... 102
5.2.5.10 Set Monitor Tag.................................................................................................................................. 103
6 PRODUCT NUMBERS & PARTS LIST.....................................................................104
6.1 Monitors............................................................................................................................................104
6.2 Sensors.............................................................................................................................................104
6.3 Options & Accessories...................................................................................................................104
6.4 Spare Parts.......................................................................................................................................104
6.5 Calibration Equipment....................................................................................................................105
6.6 Zero Calibration Gases...................................................................................................................105
6.7 Calibration Gases1...........................................................................................................................105
7 APPENDIX A: DECLARATION OF CONFORMITY..................................................107

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8 APPENDIX B: SPECIFICATIONS.............................................................................108
9 APPENDIX C: TROUBLESHOOTING GUIDE..........................................................109
10 APPENDIX D: TUV CERTIFICATION.......................................................................111
11 APPENDIX F: RETURNED MATERIAL AUTHORIZATION.....................................112
12 APPENDIX G: CONFIGURATION REFERENCE.....................................................113
13 APPENDIX H: MOUNTING DRAWINGS ..................................................................119

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 7
Packing List and Notices
You should have the following items:
SensAlarm Plus, Universal Gas Monitoring System User Manual
A SensAlert Plus Sensor Datasheet (1 – 4 pages)
A reversible black screwdriver with magnetic end
A gray PVC Sensor Shield
User Manual (this document)
SensAlert Plus Sensor is sold separately.
Please contact factory for a complete list of available sensors.
Verify that 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 owners of the SensAlarm Plus Universal Gas
Monitoring System. 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
© 2009, 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, SensAlarm, SensAlarm Plus, the SensAlert & SensAlert Plus logos,
ToD & 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 SensAlarm Plus Gas Monitor 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 SensAlarm Plus Universal Gas Monitoring System. 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.

SensAlarm Plus – Universal Gas Monitoring System User Manual
Page 8 Document No. 360-0126-01 (Rev. D)
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.
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)
(See Section 0 for details).
ALWAYS operate this product in its intended manner. Failure to do so may result in serious personal injury or
death.
Users should refer to MSDS and suppliers’ instructions for proper safety instructions and handling for any
chemicals used with this equipment.

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 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. 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 SensAlarm Plus Universal Gas Monitoring System 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 Toxic gas may cause the sensor to produce
erroneous readings.
Always make use of a Rainshield to protect against variations caused by environmental conditions. Note that
reactive Gases such as ETO, HF, HCN, NO2, SO2, HCl, ClO2, or Cl2are not compatible with the Rainshield.
Perform tests only within the specified operating ranges.
Sudden changes in pressure may cause temporary fluctuations in the sensor reading.
Sensors should be hot-swapped only when the Normal Operation Mode screen is displayed.
Caution - Failure to read and understand the User Manual may result in preventable severe
personal injury or death.
Caution, risk of electric shock if front cover is opened.
Important Calibration Considerations:
Verify the concentration of calibration gas before making calibration adjustments.
The concentration can be altered by:
Deterioration of the gas concentration during storage.
Interaction of the calibration gas with materials used to contain and transfer the gas (tubing), as for
example, absorption onto and permeation through certain plastics, polymers and elastomers.
Interaction of the calibration gas with ambient contaminants, such as water.
If further translation is required, please contact the Sensidyne EU Authorized Representative (see Back Cover
for contact information).

SensAlarm Plus – Universal Gas Monitoring System User Manual
Page 10 Document No. 360-0126-01 (Rev. D)
1Introduction
This manual provides specific information concerning the installation, operation, calibration, and
maintenance of the SensAlarm Plus Universal Gas Monitoring System. SensAlarm Plus is capable
of detecting the presence of potentially hazardous concentrations of Combustible vapors and gases,
Toxic gases and Oxygen deficiency.
1.1 Product Versions
The SensAlarm Plus Gas Monitor is offered in four versions.
820-0301-01
Single Strobe (Red, left position)
820-0301-02
Single Strobe and Battery Backup
820-0301-03
Dual Strobe (Amber on left)
820-0301-04
Dual Strobe and Battery Backup
A standard SensAlarm Plus Monitor consists of electronics
modules (PCAs) in a fiberglass enclosure, a sensor interface
assembly, and a plug-in sensor specifically designed to detect a
target gas or vapor.
A large format 4-Digit LED display provides readout for gas
concentration. A red strobe (or Amber and Red) flashes during
configured alarm and warning conditions. A 95dB sounder also
activates during the alarm and warning conditions. The sounder
can be silenced with a red pushbutton switch. The alarm reset
conforms to ISA alarm sequence 3A
Product specifications for the SensAlarm Plus are in Appendix B,
Specifications.

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 11
1.2Standard Features
1.2.1 Universal Sensor Capability
The SensAlarm Plus Monitor unit accepts a variety of sensor technologies,
including electrochemical, catalytic bead Combustible, and infrared
Combustible. Sensors can be installed without having to reconfigure or modify
the Monitor in any way. When a different SensAlert Plus sensor type is
installed in the Monitor the unit completely reconfigures the system functions
to match those of the new sensor. This includes changing all alarm and
calibration settings to match those of the new sensor.
1.2.2 Large Displays for Ease of Operation
The Monitor has a large format 4-digit LED display for gas concentration and a
backlit LCD with magnetic controls.
1.2.3 Non Intrusive Operation
Four magnetic switches on the backlit LCD allow full configuration, calibrations
and other functions to be performed without opening the Monitor enclosure. A
magnetic screwdriver is provided with the monitor.
1.2.4 Transportable Calibration
SensAlert Plus sensors have transportable calibration capabilities. Sensors
may be calibrated in the shop or at Sensidyne and then installed in the field
without any special tools or adjustments. When a new sensor is installed in the
unit, the Monitor automatically adjusts to recognize the new gas type and
range and adjusts system function accordingly.
1.2.5 Predictive Failure
Predictive Failure is a unique feature that provides the user with an early
warning of the pending expiration of a sensor. When the sensor has less than
10% of its life remaining, a warning appears on the main display, and can be
assigned to activate other warning indicators.
Predictive failure is based on sensor age, power on hours, calibration gain and
cumulative gas exposure. The user can also display Remaining Sensor Life
(percent) at any time.
1.2.6 AC & External DC Power Capability
SensAlarm Plus has an internal power supply for operation from 100-240
VAC, 50/60 Hz and rated at 24 VDC, 65 watts output. 24 VDC is used to
power the annunciation, so that the monitor is fully functional on external 24
VDC or internal battery back-up when furnished.
The optional, internal battery back-up will power the unit in the event of a
power failure. It provides 30 minutes operation in full alarm and 60 minutes
minimum when not in alarm, depending upon the installed sensor type.

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Page 12 Document No. 360-0126-01 (Rev. D)
1.3 Factory Installed Options
1.3.1 Test-On-Demand™ Gas Generator
The SensAlert Plus Test On-Demand™ (ToD) feature allows the gas sensor
response to be confirmed quickly and easily. When activated, either manually,
or at programmed times, the ToD™ cell generates a small gas output which
should produce a signal from the gas sensor to verify that it is responsive to
gas. This un-manned “bump test” does not replace recommended calibration
procedures. The purpose of this feature is to provide a higher level of system
operating confidence by confirming that the sensor responds to gas. This
feature can be activated via the LCD display, or automatically using the Test
Date/Time menu. Environmental conditions or ToD cell depletion can cause
this test to fail. A low mA signal for 30 seconds will indicate failure or a relay
may also be assigned.
1.3.2 Remote Sensor Operation
The sensor is mounted in a sensor interface assembly on the bottom of
SensAlarm Plus. It can, however, be located up to 100 feet away. In this
manner, the detection of heavier or lighter than air gases and the use of
special fixtures such as sample draw or duct mounting can be easily done.
The sensor interface is connected without special cable or conduit. Sensidyne
furnishes all hardware to remote mount the sensor except for the 4 conductor
shielded cable.
1.3.3 Communication Options
An optional Communications PCA can be installed for RS-485 Modbus
Protocol, or HART Protocol.
821-0221-01 RS 485, Modbus Protocol
821-0220-01 HART
1.3.4 Dual Strobes
When two strobes are ordered, an Amber strobe will be mounted on the left side
and the Red strobe will be on the right. Different color strobe lens are available,
consult the factory.
1.3.5 Internal 30 Minute Battery Backup
An integral battery back-up option with internal charging is offered for those
applications with frequent power interruptions, or to provide SensAlarm Plus
operation in the event of power failure. If a gas alarm occurs during battery
back-up, a minimum of 30 minutes operation is available. The unit will
operate for a much longer time if there are no alarms and depending upon the
installed sensor type.

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 13
1.4 SensAlarm Plus Components
1.4.1 Sensor Interface Assembly
The sensor interface assembly contains the electronics that operate the
sensor and houses the SensAlert Plus sensor and the optional Test-on-
Demand™ cell.
1.4.2 SensAlert Plus Sensor
SensAlert Plus Sensors are available in a variety of sensor technologies for
detecting Toxic, Oxygen, and Combustible gases. The SensAlert Plus Sensor
is discussed in greater detail in Section 1.4.8. The sensor gasket seals the
sensor inside the sensor holder.
1.4.3 Test-on-Demand™
The optional Test-on-Demand™ (ToD™) gas generating cell provides a
method for periodic sensor response verification (programmed or manually
activated). The T-O-D gasket seals the generating cell inside the sensor
holder.
1.4.4 Sensor Holder
The sensor and ToD™ gas generating cell are housed in the Sensor Holder.
The sensor holder is easily installed and removed via the retaining ring located
on the sensor interface assembly. The sensor holder is black anodized
Aluminum and optional gray PVC.
1.4.5 Rainshield
The optional rainshield protects the sensor and ToD cell from liquid
intrusion due to rain, splash-back, or unintentional washdown. Reactive
Gases such as ETO, HF, HCN, NO2, SO2, HCl, ClO2, or Cl2are not
compatible with the Rainshield.
1.4.6 Calibration Plug Assembly
The calibration plug assembly secures into the sensor shield or replaces the
Rainshield when the Monitor is being calibrated.

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Page 14 Document No. 360-0126-01 (Rev. D)
Single or Dual Strobes
(Red or Amber and Red)
Large Format LED Display
Power Source Available LEDs
AC External DC Battery
Magnetic Controls (OK <<)
LCD Display
Magnetic Controls (ST)
Reset Switch
And Sounder
Interface Assembly
(Sensor Head)

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 15
1.4.7 Liquid Crystal Display and Magnetic Controls
The Liquid Crystal display is backlit and has a contrast adjustment.
nGas Concentration or Value
The gas concentration is displayed in large characters with the units of measure (ppm, %vol, %LEL), as
required by the installed sensor. This information is automatically retrieved from the sensor on power up.
oGas Type & Maximum Sensor Range
Displays the chemical symbol or abbreviated name of the target gas sensor installed in the Monitor.
The range of the sensor is displayed to the right on the same line.
pLocal Date and Time
The date can be user formatted. The
time is displayed in a 24 hour format.
qMonitor Name or ID
User-entered field for Monitor
identification.
rOK Control (Magnetic Switch)
OK is one of the four magnetic switches
used to operate the SensAlarm Plus menu.
OK is used to confirm operations or select
a menu item. Activating OK from the Main
Display brings up a menu listing the
operations that can be performed.
s<< (Go Back)
<< is the opposite of OK. If you change
your mind while performing any operation,
activating << will take you back to the
previous operation.
tŸand ź
The Ÿand źcontrol arrows are used to scroll up or down the menu and to increase or decrease a value
(such as an alarm Setpoint). Holding the wand near these magnetic switches causes the displayed value to
increase or decrease.
uRed LEDs 1 through 4
The LCD display has four Red LEDs that light to confirm that magnetic switch contact has been made with
the magnetic wand. They also light when an alarm or fault condition is occurring.
Each Red LED is also associated with the respectively numbered alarm relays. LED 1 (Relay 1) is factory
set as the “fault” LED/Relay. LED 2, 3 and 4 are associated with relays 2, 3, and 4.
vThis line is used for important system messages and warnings such as “Alarm 1 is On.”

SensAlarm Plus – Universal Gas Monitoring System User Manual
Page 16 Document No. 360-0126-01 (Rev. D)
1.4.8 Sensor Types
NOTE
DO NOT attempt to install any other sensor type into a SensAlarm Plus except those manufactured by
Sensidyne and intended for this product.
A complete list of available sensors, sensor specifications, interferences, and calibration equipment
can be found on line at www.sensidyne.com.
Sensors should be hot-swapped only when the Normal Operation Mode screen is displayed.
Sensor Types
Infrared
Infrared sensors are used to detect Combustible gases or vapors
and Carbon Dioxide.
Catalytic Bead Combustible
Catalytic Bead sensors are used to detect Combustible gases and vapors.
Sealed Electrochemical
Sealed electrochemical sensors are used to detect Toxic gases.
Oxygen
Oxygen sensors are used to monitor ambient Oxygen levels
to detect Oxygen Deficiency.
Sensor Assembly
The sensor assembly consists of a gas sensor attached to a circuit board. An
EEPROM on the circuit board contains essential sensor identification information that
is communicated to SensAlarm Plus during sensor installation. This information
allows the sensor to be calibrated in the shop or at Sensidyne and hot-swapped in
the field without further calibration.
Note: Oxygen and Infrared Sensors must be calibrated at the altitude of use.

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 17
NOTE
The ETO, NO and 100 PPM HCl sensors are shipped with battery boards
attached to maintain a sensor bias. Batteries are designed to maintain
biasing for up to 90 days. Battery boards should remain attached to the
sensor until just prior to sensor installation, and should be removed in a
non hazardous (classified) safe area just prior to installation of the
sensor into the SensAlarm Plus Monitor. The sensor can be unplugged
from the battery board for a maximum of 5 minutes. Note that, if
unplugged or unpowered for 15 seconds, a sensor may take 2 minutes to
return to zero once it is plugged into a Monitor or powered up. If
unplugged or unpowered for 5 minutes, a sensor may take several hours
to return to zero once it is plugged into a Monitor or powered up.
NOTE
If the sensor is not installed or not completely engaged, “Missing
Sensor” is displayed on LCD display. The Monitor’s 4-20mA output
returns a “Loop-Fail” condition by providing an unvarying default output
of < 3.0 mA (user adjustable 1-4mA).
1.4.9 SensAlarm Plus Housing
The product housing is a NEMA 4X Fiberglass enclosure. When the optional
battery back-up is ordered, the enclosure is vented and the rating becomes
NEMA 3R, IPX4. The raw enclosure is UL listed.
1.4.10 SensAlarm Plus Power Available LED (3)
Three green LEDs are below the large format display to indicate what power sources are available for
operation. Normal operation would be from AC power or external 24 VDC power. Note that both LEDs (AC
Power, External DC) will be on when both power sources are available.
Installed integral battery back-up is indicated by the third LED being illuminated. This power source will only be
used in the event that the primary power source(s) are not available.
1.4.11 Red Strobe
The standard base SensAlarm PLUS includes one Red Strobe Annunciation
light which actuates on low and high alarms. The strobe is a double flash, high
recognition unit approved to SAE J1318 Class 3 for gaseous discharge
warning lamps. The 2.2 Joule strobe has Fresnel lens optics and double-
flashes 70 times per minute.
MAINTENANCE
WARNING: High voltage generated by the light’s power supply may cause
property damage, serious injury or death to you or others. Ensure that power
to light is disconnected and wait at least 5 minutes before working on the light.
As strobe lights are used, the flash tubes begin to darken, decreasing light
output. Also, as flash tubes age, they may have a tendency to misfire.
After extended operation, occasionally check for flash tube degradation.
Should the flash tube misfire, have a noticeable decrease in light output or
glow continuously, it should be replaced. To replace the flash tube, proceed
as follows:
A. Disconnect power.
B. BE CAREFUL! Use GLOVES and EYE PROTECTION to avoid personal
injury in the following procedure.
C. Twist the lens (1) counter-clockwise to remove it from the base.
D. The Flash tube can be removed by grasping and pulling upward on the
white potted base.

SensAlarm Plus – Universal Gas Monitoring System User Manual
Page 18 Document No. 360-0126-01 (Rev. D)
E. CAUTION: The service life of the new strobe tube will be shortened if the glass portion is touched. If glass
has been handled, clean carefully with a grease solvent.
F. Install a new flash tube. Observe handling caution.
G. Reassemble the light by replacing the lens.
H. Reconnect power and test for proper operation.
1.4.12 Amber Strobe (option)
A second strobe is optional for SensAlarm PLUS. When this is ordered, An Amber strobe is placed on the left
and the Red strobe is on the right. The Amber strobe will flash on low alarm and high alarm. The red strobe
flashes only on high alarm. The strobe specifications and maintenance are the same as described above.
1.4.13 Sounder
A 95dB Piezo horn is located on the bottom right side of the enclosure. The sounder activates during alarm and
warning conditions. The sounder can be silenced with a red pushbutton switch. The alarm reset conforms to
ISA alarm sequence 3A.
1.4.14 Reset Button
SensAlarm PLUS has a Red Alarm Reset Pushbutton on the bottom right side of the enclosure. This
Pushbutton can be used to reset or release a latched Alarm Relay and / or to silence the Piezo horn on the
enclosure. This function conforms to ISA Alarm Sequence 3A, that is, when the local horn is silenced, the
Strobe Annunciation will continue to flash and the associated Alarm Relays will remain energized. If the unit
goes out of alarm and then back into alarm, the horn will resume until the Reset Pushbutton is depressed
again.
The high Alarm Relay in SensAlarm is not affected by the Reset Button so a remote horn cannot be silenced.
The latched Alarm relays can only be released by pushing the Reset button, however they will release only
when the unit is not in Alarm.

User Manual SensAlarm Plus – Universal Gas Monitoring System
Document No. 360-0126-01 (Rev. D) Page 19
c
d
TB1
TB
2
ef
g
h
i
AC Fuses
DC Fuses
Test Points
TB1
1.5 Electronics Modules
The electronic modules operate the sensor, determine sensor response, actuate the alarm relays, turn on the
annunciation (horn and strobe), converts the sensor response into a 4–20 mA current, linearly proportional to
the concentration of the target gas present at the sensor, and optionally provide RS 485 Modbus or HART
communications protocol output. The sensor response reading is displayed on both the LCD and large format
LED Displays.
Power On-Off Switch
(AC & External DC)
c
Alarm Relays (4)
d
Main PCA
Door Ribbon Cable
AC Power In TB1
DC Power In TB2
DC Fuses
e
Optional Comm. PCA
f
4-20 mA Output
Test Points
Optional Batteries
g
Sensor Input Barrier
h
Battery Charger
95 dB Sounder
i
Reset Switch
The SensAlarm Plus Monitor has non-intrusive controls that do not require the enclosure to be opened
for calibration, alarm adjustment, or other functions. However, test points are provided on the main
PCA in case service personnel wish to monitor the output.
An internal 10 ohm resistor between test points TP2 and TP3 in series with the output loop current of 4–20 mA
produces a voltage across the test points of 40–200 mv, corresponding to the sensor range.
NOTE
A HIGH IMPEDANCE VOLTMETER (PREFERABLY DIGITAL), WITH A MINIMUM FULL SCALE
CAPABILITY OF 200 MV AND A RESOLUTION OF ±1 MV, IS REQUIRED TO MONITOR VOLTAGE AT
THE TEST POINTS.
TB5 TB6 TB7 TB4
K2 K3 K4 K1

SensAlarm Plus – Universal Gas Monitoring System User Manual
Page 20 Document No. 360-0126-01 (Rev. D)
TB1
TB2
AC Fuses
DC Fuses
1.5.1 Display PCA
The front and rear views of the Display LCD PCA are shown below about half of actual size on the printed
page. The Display PCA back is barely visible inside the front cover of SensAlarm Plus. The display contrast
adjustment can be reached with a finger.
Display
Adjust
Underneath
1.5.2 LED display (4-digit) PCA
The front and rear views of the large format display are shown below about half of actual size on the printed
page. There are no user adjustments.
1.5.3 Power Assembly TB1, TB2
AC Power and, or External 24 VDC Power are connected to
TB1 and TB2, respectively. The external DC power fuses are
shown on the lower left. The AC fuses are located under the
metal shroud for safety and can be accessed by removing the
four (4) screws.