GasTech D-Guard2 User manual

INSTRUCTIONMANUAL
t+61 8 6108 0000 e[email protected] wgastech.com
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D-Guard² Instruction Manual
Item Number 2010182
1Introduction
The D-Guard general purpose is a single gas fixed detector with a large range of
available sensors and an easy to use interface.
Figure 1. D-Guard² .
2Method of Operation
The D-Guard detects toxic or flammable gas and can interface with external
equipment to trigger alarms or operate additional equipment. The D-Guard can be
fitted with an oxygen sensor to measure the oxygen concentration in the environment.
The D-Guard detects gas via diusion to the sensor at normal atmospheric pressure.
3For Your Safety
WARNING: You must obey the instructions for the safe installation, use, and
maintenance of this equipment.
4Further Information
Please tell us if you want help with this equipment.
Head Oce: Gastech, 24 Baretta Road, Wangara, WA 6065, Australia.
Phone: [phone] Email: [email protected] Website: gastech.com
NOTE: Modification of this equipment is strictly prohibited without written permission from
Gastech Australia Pty Ltd.

D-Guard² Instruction Manual
Item Number 2010183
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 
Method of Operation . . . . . . . . . . . . . . . . . . . . . . . 
For Your Safety . . . . . . . . . . . . . . . . . . . . . . . . . 
Further Information . . . . . . . . . . . . . . . . . . . . . . . . 
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . 
Keywords and Symbols Used in This Manual . . . . . . . . . . . . . . . 
Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . 
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . 
Models covered by this instruction manual . . . . . . . . . . . . . . . . 
What is in the Box? . . . . . . . . . . . . . . . . . . . . . . . . 
Installation Information . . . . . . . . . . . . . . . . . . . . . . 
.D-Guard Mechanical Installation . . . . . . . . . . . . . . . . . 
Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . 
Response Test . . . . . . . . . . . . . . . . . . . . . . . . . 
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 
.Power up . . . . . . . . . . . . . . . . . . . . . . . . . 
.Home screen features . . . . . . . . . . . . . . . . . . . . . 
.Unlock the menu screen . . . . . . . . . . . . . . . . . . . . 
.Passcode Requested . . . . . . . . . . . . . . . . . . . . . 
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . 
.Access the calibration menu . . . . . . . . . . . . . . . . . . . 
.Attach the calibration gas to the D-Guard . . . . . . . . . . . . . . 
.Calibration Modes . . . . . . . . . . . . . . . . . . . . . . 
.Calibration Trend Bar . . . . . . . . . . . . . . . . . . . . . 
.Auto Zero Calibration. . . . . . . . . . . . . . . . . . . . . . 
.Auto Span Calibration . . . . . . . . . . . . . . . . . . . . . 
.Manual Zero Calibration . . . . . . . . . . . . . . . . . . . . 
.Manual Span Calibration . . . . . . . . . . . . . . . . . . . . 
System Information. . . . . . . . . . . . . . . . . . . . . . . . 
Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
.Clear Latched Alarms . . . . . . . . . . . . . . . . . . . . . 
Sensor Settings . . . . . . . . . . . . . . . . . . . . . . . . . 
.Access the Sensor Settings Menu . . . . . . . . . . . . . . . . . 
.Set Detector Full Scale. . . . . . . . . . . . . . . . . . . . . 
.Set Span Gas Concentration . . . . . . . . . . . . . . . . . . . 
.Set Zero Gas Concentration . . . . . . . . . . . . . . . . . . . 
.Set Suppression Band . . . . . . . . . . . . . . . . . . . . . 
.Sensor Gain . . . . . . . . . . . . . . . . . . . . . . . . 
Alarm Settings . . . . . . . . . . . . . . . . . . . . . . . . . 
.Access the Alarm Settings menu . . . . . . . . . . . . . . . . . 
.Alarm Direction . . . . . . . . . . . . . . . . . . . . . . . 
.Alarm Level . . . . . . . . . . . . . . . . . . . . . . . . 
.Alarm Relay state . . . . . . . . . . . . . . . . . . . . . . 
.Alarm Latch . . . . . . . . . . . . . . . . . . . . . . . . 
.Latched Alarm Examples . . . . . . . . . . . . . . . . . . . . 
System Settings . . . . . . . . . . . . . . . . . . . . . . . . . 
.Access the System Settings . . . . . . . . . . . . . . . . . . . 
.Isolate . . . . . . . . . . . . . . . . . . . . . . . . . . 

D-Guard² Instruction Manual
Item Number 2010184
.Set Passcode . . . . . . . . . . . . . . . . . . . . . . . . 
.Disable Passcode . . . . . . . . . . . . . . . . . . . . . . 
Advanced Settings . . . . . . . . . . . . . . . . . . . . . . . . 
.Access the Advanced Settings Menu . . . . . . . . . . . . . . . . 
.System Calibration . . . . . . . . . . . . . . . . . . . . . . 
.-mA Output Test . . . . . . . . . . . . . . . . . . . . . 
.Relay Function Test . . . . . . . . . . . . . . . . . . . . . . 
.Reset Sensor Life . . . . . . . . . . . . . . . . . . . . . . 
.Sensor Presets . . . . . . . . . . . . . . . . . . . . . . . 
Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . 
-mA Output Fault Conditions . . . . . . . . . . . . . . . . . . . 
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 
.Enclosure Specifications . . . . . . . . . . . . . . . . . . . . 
.Mechanical Specifications. . . . . . . . . . . . . . . . . . . . 
.General Specifications . . . . . . . . . . . . . . . . . . . . . 
.Wiring Requirements . . . . . . . . . . . . . . . . . . . . . 
.D-Guard General Versions, Gas, Range, and Resolution . . . . . . . . . 
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . 
.Sensor Warranty periods . . . . . . . . . . . . . . . . . . . . 
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . 
.Replacement Parts - exploded view . . . . . . . . . . . . . . . . 
.Replacement parts - list . . . . . . . . . . . . . . . . . . . . 
PCB (Part number -) Configuration Jumpers . . . . . . . . . . . . 
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . 
.Calibration Interval . . . . . . . . . . . . . . . . . . . . . . 
.Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . 
.Visual Inspection. . . . . . . . . . . . . . . . . . . . . . . 
Gastech Policy Statements . . . . . . . . . . . . . . . . . . . . . 

D-Guard² Instruction Manual
Item Number 2010185
5List of Figures
Figure .D-Guard . . . . . . . . . . . . . . . . . . . . . . . . 
Figure .Keywords and symbols used in this manual. . . . . . . . . . . . . 
Figure .List of supplied items.. . . . . . . . . . . . . . . . . . . . 
Figure .D-Guard mounting dimensions in millimetres. . . . . . . . . . . . 
Figure .Arrows show magnetic sensor positions. . . . . . . . . . . . . . 
Figure .D-Guard menu icons. . . . . . . . . . . . . . . . . . . . 
Figure .D-Guard splash screen. . . . . . . . . . . . . . . . . . . . 
Figure .D-Guard at sensor warm up. . . . . . . . . . . . . . . . . . 
Figure .D-Guard normal operating screen. . . . . . . . . . . . . . . . 
Figure .Main display layout. . . . . . . . . . . . . . . . . . . . . 
Figure .Menu locked. . . . . . . . . . . . . . . . . . . . . . . 
Figure .Menu unlocked. . . . . . . . . . . . . . . . . . . . . . 
Figure .Trend Bar states. . . . . . . . . . . . . . . . . . . . . . 
Figure .Sensor Gain Warning. . . . . . . . . . . . . . . . . . . . 
Figure .Span Gas Concentration Warning. . . . . . . . . . . . . . . . 
Figure .Zero Gas Concentration Warning. . . . . . . . . . . . . . . . 
Figure .Sensor gain warning . . . . . . . . . . . . . . . . . . . 
Figure .Minimum alarm level warning. . . . . . . . . . . . . . . . . 
Figure .Maximum alarm level warning. . . . . . . . . . . . . . . . . 
Figure .AL Latched. . . . . . . . . . . . . . . . . . . . . . . 
Figure .AL and AL Latched. . . . . . . . . . . . . . . . . . . . 
Figure .AL Latched. . . . . . . . . . . . . . . . . . . . . . . 
Figure .D-Guard home screen when isolated. . . . . . . . . . . . . . 
Figure .Error codes. . . . . . . . . . . . . . . . . . . . . . . 
Figure .- mA output loop fault currents. . . . . . . . . . . . . . . 
Figure .D-Guard dimensions in millimetres (front view). . . . . . . . . . . 
Figure .D-Guard dimensions in millimetres (side view). . . . . . . . . . . 
Figure .D-Guard mechanical specifications. . . . . . . . . . . . . . . 
Figure .D-Guard General Specifications. . . . . . . . . . . . . . . . 
Figure .D-Guard electrical connections. . . . . . . . . . . . . . . . 
Figure .D-Guard general versions. . . . . . . . . . . . . . . . . . 
Figure .Sensor warranty periods in months. . . . . . . . . . . . . . . 
Figure .D-Guard replacement parts - exploded view. . . . . . . . . . . . 
Figure .D-Guard replacement parts list. . . . . . . . . . . . . . . . 
Figure .PCB - jumper locations. . . . . . . . . . . . . . . . . 
Figure .PCB - jumper settings. . . . . . . . . . . . . . . . . 
Figure .Splash Guard. . . . . . . . . . . . . . . . . . . . . . . 

D-Guard² Instruction Manual
Item Number 2010186
6Keywords and Symbols Used in This Manual
Symbol Keyword Description
Warning WARNING: Do not (warning text). Can cause injury or
death to personnel.
No
Symbol Caution CAUTION: Do not (caution text). Can cause damage to parts or equipment.
Service tool Combined magnetic wand and hex key service tool
Calibration plug Calibration adapter
No
Symbol Full Scale The user selectable range of the detector. This cannot exceed the maximum range of the sensor.
No
Symbol Suppression Band The suppression band prevents the D-Guard from
displaying small changes in the detected gas level
close to zero.
No
Symbol Sensor Gain The sensor gain adjusts the amplification of the sensor output.
No
Symbol AL1 User configurable Alarm 1
No
Symbol AL2 User configurable Alarm 2
No
Symbol IP Ingress Protection Rating
Figure 2. Keywords and symbols used in this manual.

D-Guard² Instruction Manual
Item Number 2010187
7Intended use
The D-Guard is designed as a fixed gas detector with a 4-20 mA current loop output.
The detector can interface with external equipment to transmit gas levels and trigger
external alarm devices.
WARNING: The D-Guard detects toxic and flammable gases and oxygen
concentrations. These gases can cause injury or death to personnel.
WARNING: The D-Guard is not a personal gas detector. If you do not use a
personal gas detector this can cause injury or death to personnel.
WARNING: Do not use the D-Guard in an explosive or oxygen rich
atmosphere. An explosion can cause injury or death to personnel.
8Safety Precautions
Read all safety warnings before you install or operate this equipment.
WARNING! You must do a response test before first use. Incorrect calibration can
result in injury or death to personnel.
9Models covered by this instruction manual
CAUTION: This manual is intended for the non-certified general version of the
D-Guard. Do not use this manual for other models in our range.
Please refer to section 24.5 for a list of all models covered by this manual.

D-Guard² Instruction Manual
Item Number 2010188
10What is in the Box?
Item Description
D-Guard gas detector
D-Guard Service Tool. The service tool activates
the internal menu magnetic sensors and includes an
integrated 4mm hex key to open the enclosure.
The Quick Start Guide (QSG) provides a brief overview
of the installation and operation of the D-Guard gas
detector.
Calibration Certificate. The D-Guard is factory calibrated
before dispatch.
Calibration plug
Figure 3. List of supplied items.

D-Guard² Instruction Manual
Item Number 2010189
11Installation Information
WARNING: The D-Guard² must be installed by an approved person. Incorrect
installation can cause injury or death to personnel.
11.1 D-Guard² Mechanical Installation
The D-Guard should be mounted vertically to a suitable flat surface. Make sure the
cable gland faces the ground. Use the two mounting eyes with M6 fasteners suitable
for the surface type. Make sure the data plate, on the right hand side, remains visible
after installation.
CAUTION: Do not over tighten the M6 fasteners as this can cause distortion of the enclosure.
CAUTION: Water or dust on the splash guard can interfere with gas detection.
Figure 4. D-Guard² mounting dimensions in millimetres.
Splash Guard

D-Guard² Instruction Manual
Item Number 20101810
12Electrical Installation
WARNING: The D-Guard² must be installed by an approved person. Incorrect
installation can cause injury or death to personnel.
Step 2. Open the D-Guard² enclosure.
Socket Head
Cap Screws
Socket Head
Cap Screws
Step 1. Loosen the 4 screws holding the top case on.

D-Guard² Instruction Manual
Item Number 20101811
Step 3. Connect the D-Guard² as shown. The DC supply voltage range is 13 - 28 V.
CAUTION: The outside diameter of the cable must be between 10 mm and 14 mm. Use a
twin core shielded cable. Make sure the cable is sealed by the M20 cable gland to prevent
moisture ingress.
13Response Test
The D-Guard has been calibrated before dispatch.
CAUTION: You must recalibrate the D-Guard² if its results do not agree with this
specification. See section 15.
CAUTION: The D-Guard² must be response tested when it is first commissioned and as
necessary during use.
Step 1. Apply gas to the D-Guard. See section 15.2.
Step 2. Apply the gas for at least 3 minutes or until the indicated concentration is
within ±10% of the applied gas concentration. Gas flow rate must be greater than or
equal to 1L/min.
CAUTION: You must use a circular cross-section cable. Non-circular cross-section cables can
leak between the sheath and the cable gland.

D-Guard² Instruction Manual
Item Number 20101812
14Operation
Figure 5. Arrows show magnetic sensor positions.
Figure 6. D-Guard² menu icons.
Icon Description Icon Description Icon Description Icon Description
Locked Alert Alarm Increase
Calibrate Home Alarm muted Decrease
Information Settings Alarm latched Skip
Down Up Accept Start
Left Right
NOTE: If an icon is not shown, that adjacent magnetic sensor has no function on that screen.
D
The D-Guard menu system is controlled by the magnetic service tool (supplied). Four
magnetic sensors, located behind the display window, are activated by the service
tool. The four marks on the D-Guard display match the magnetic sensor positions.
The menu system uses custom icons and text to give information to the user. To
access a function, use the magnetic service tool on the magnetic sensor that is next to
the icon displayed on the screen.

D-Guard² Instruction Manual
Item Number 20101813
14.1 Power up
Connect power to D-Guard and energise the unit.
NOTE: The D-Guard² is ready for use after the one minute warm up has ended.
Figure 7. D-Guard² splash screen.
Figure 8. D-Guard² at sensor warm up.
Figure 9. D-Guard² normal operating screen.
WARNING! You must do a response test before first use. Incorrect calibration can
result in injury or death to personnel.

D-Guard² Instruction Manual
Item Number 20101814
14.2 Home screen features
The home screen is the main display that will be visible. It shows the installed gas
sensor, range and the current reading. System alerts are displayed at the bottom.
Figure 10. Main display layout.
14.3 Unlock the menu screen
Put the service tool over the magnetic sensor location closest to the padlock icon for
at least one second to unlock the D-Guard.
NOTE: If no passcode is set the menu system will unlock.
D
Magnetic Sensor location Sensor type and range
Menu
locked
System status messages location
The D-Guard is normally locked and must be unlocked with the supplied service tool.
Figure 11. Menu locked. Figure 12. Menu unlocked.

D-Guard² Instruction Manual
Item Number 20101815
14.4 Passcode Requested
NOTE: The Enter Passcode screen only appears when a passcode has been set.
Please Contact Gastech if you have forgotten the passcode.
Step 1. Change the value with the keys. Step 2. Accept the value with the key.
Step 3. Accept the value with the key. Step 4. Accept the passcode with the key.
Step 5. The menu is unlocked.
You must enter the passcode when prompted.
NOTE: The line below the number indicates which digit will change.

D-Guard² Instruction Manual
Item Number 20101816
15Calibration
Step 1. Use to enter the calibration menu.
WARNING! Incorrect calibration can result in injury or death to personnel.
Put the service tool over the magnetic sensor location closest to the gas cylinder icon
for one second to access the calibration menu.
15.1 Access the calibration menu
Make sure the menu system is unlocked. See section 14.3.
Step 2. Use to continue or to go back.
Step 3. Calibration menu.
NOTE: If CANCEL was selected, the menu will auto lock after a ten second delay.
WARNING! Use the calibration plug for each calibration or bump test. Incorrect
calibration can result in injury or death to personnel.
The D-Guard is factory calibrated before dispatch. You must calibrate the D-Guard
regularly. Calibration adjusts the response of the D-Guard to known concentrations of
gas at two points, zero and span.
Zero calibration uses zero-grade air or fresh air, which does not contain any trace of
the detectors intended target gas. You can set the concentration of zero calibration
gas. See section 18.4.
Span calibration uses a known concentration of the intended target gas. You can set
the concentration of span calibration gas. See section 18.3.

D-Guard² Instruction Manual
Item Number 20101817
15.2 Attach the calibration gas to the D-Guard²
The D-Guard is a normally aspirated gas detector that operates at normal
atmospheric pressure. A calibration plug is provided to make sure that gas is applied
directly to the sensor.
Step 1. Remove the Splash Guard. Step 2. Fit the calibration plug.
Step 3. Attach tubing to the calibration plug. Step 4. Use a 1L / min fixed flow regulator.

D-Guard² Instruction Manual
Item Number 20101818
15.3 Calibration Modes
Figure 13. Trend Bar states.
Trend Bar State Concentration Percentage full scale
Rate of change / second
Falling > 3%
Falling 1% < x ≤ 3%
Falling 0.1% ≤ x ≤ 1%
Stable < ± 0.1%
Rising 0.1% ≤ x ≤ 1%
Rising 1% < x ≤ 3%
Rising > 3%
The D-Guard has a trend bar to show the detected rate of change of the applied gas.
The trend bar has seven dierent positions and provides a clear visual indication of
the rate of change of the detected gas concentration levels.
15.4 Calibration Trend Bar
The D-Guard has two calibration modes, Auto and Manual.
The Auto calibration mode checks that the rate of change of the detected gas has
decreased to less than ± 0.1% of full scale per second, and adjusts the D-Guard
response automatically.
The Manual calibration mode allows the user to adjust the D-Guard calibration when
the response has stabilised.
Use the Trend Bar to determine when the rate of change of the detected gas has
decreased to less than ± 0.1% of full scale per second.

D-Guard² Instruction Manual
Item Number 20101819
15.5 Auto Zero Calibration.
Step 2. Apply the correct gas. Use to start.
Step 3. Use to save or to cancel. Step 4. Use to exit or to continue.
WARNING! Incorrect calibration can result in injury or death to personnel.
NOTE: Fresh air can be used in place of zero-grade air.
Step 1. Use to go into the auto zero mode.
Step 5. Use to exit or to cancel. Step 6. Calibration completed.
NOTE: The D-Guard² Auto Calibration mode determines when the rate of change of the
applied gas has decreased to less than ± 0.1% of full scale per second.
Access the calibration menu. See section 15.1.
CAUTION: You must monitor the alarm states before you exit the calibration menu, as alarms
may remain active until the calibration gas has been removed from the sensor.

D-Guard² Instruction Manual
Item Number 20101820
15.6 Auto Span Calibration
Step 4. Use to exit or to continue.
WARNING! Incorrect calibration can result in injury or death to personnel.
Step 3. Use to save or to cancel.
Step 1. Use to go into the auto span mode.
NOTE: The D-Guard² Auto Calibration mode determines when the rate of change of the
applied gas has decreased to less than ± 0.1% of full scale per second.
Access the calibration menu. See section 15.1.
Step 2. Apply the correct gas. Use to start.
Step 5. Use to exit or to cancel. Step 6. Calibration completed.
CAUTION: You must monitor the alarm states before you exit the calibration menu, as alarms
may remain active until the calibration gas has been removed from the sensor.