Gas Detection GDA 40125 User manual

GDA 40125 Toxic Or Oxygen Gas Detection
Controller
Operating Manual
WARNING: THIS INSTRUMENT CONTAINS DELICATE COMPONENTS AVOID DROPPING OR
EXCESSIVE VIBRATION
This Sensor/Controller is designed and manufactured by
This manual must not be copied or reproduced in part without the express written permission
of Gas Detection (Australia) Pty Ltd. All information contained here is subject to modification.

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System Specification:
Power
requirements
24V DC, <25mv
ripple 0.5A
This can be supplied by plug in mains power
supply or via plug jack on side of unit
Sensors
1
GD2525-02 (Carbon Monoxide 0-200ppm)
GD2528-02 (Oxygen 0-25%VOL)
Display
2 x 12 char line back
lit LCD
Fault relays
1SPCO
Relay is energised on power up
Alarm relays
2SPCO
Alarm levels are programmable levels and can be
rising or falling latched or non latched
Alarm relay
specification
3A @ 30VDC
Non inductive load
Alarm hysteresis
0-40% of alarm
value
Analogue outputs
1
4-20mA, Max 800R loop impedance
Internal buzzer
93db 0.5M
Mutable from front panel
External buzzer
24V 100mA
Designed for: AV20R/Y - 24V Sounder and
Flasher
User interface
1 button
Mutes buzzer and resets latched alarms
2 Setup Buttons
Allows changes to controller setup (Internal)
Zero and Span
adjustment pots
Allows changes for calibration (Internal)
Test Pot
Allows simulation of a 4-20mA input. (Internal)
WARNINGS
The GD40125 Toxic Gas / Oxygen Detector and Controller is only to be used in areas classified as SAFE
AREAs. The sensor is not designed for use in classified HAZARDOUS AREAs.
The GD40125 sensor uses electrochemical sensors which have a shelf life of 6 months unpowered. If the
sensor is not powered up in this period, the sensor performance may have degraded and may require re-
calibration.
The sensor element contains substances that can be harmful to health. In the unlikely event of a sensor
element leaking, the sensor contents should not be touched. If the sensor contents come in contact with eyes
or skin, please seek immediate medical attention.
It is important not to exceed the specified voltage as indicated in this manual.

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Mounting Requirements:
Each Applications Is Unique And the Table Below Is For General Guidance
Gas
Sensor position from Ground
Oxygen (O2)
1.8m
Carbon Monoxide (CO)
1.8m
Hydrogen Sulphide (H2S)
300-500mm
Ammonia (NH3)
300-500mm
In all cases please take into account any air movement and heat sources
Avoid mounting the sensor in direct sunlight
Avoid direct water spray
Mount the sensor in the direction shown below
Mount the sensor as close as is practical to the potential source of the leak
152 mm
91 mm
20mm
20mm
10mm
10mm
6.9mm
MUTE BUTTON
SENSOR
ALARM LEDS
BACKLIT DISPLAY
Ground
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Electrical connections:
Please ensure that 24v connector is placed in the correct position or else it will damage
the circuit board if in the wrong position
Wiring Connection
Down
Set
Down
Set
NOTE:
RELAYS SHOWN DE-ENERGISED
ALARM RELAYS ENERGISE ON
ALARM
FAULT RELAY IS NORMALLY
ENERGISED AND DENERGISES ON
FAULT
Setup Buttons
24v Mutable
Sounder/Flasher
O/P
4-20mA o/p
24V DC Power
Supply
Area for
MODBUS Card
and connector if
required
Sensor Input
Calibration &
Setup Jumper
Alarm Relay Outputs
Links Must Be In Place And In This
Position For System To Work
Correctly
To Buzzer/
Flasher
24V DC
Power Supply
4-20mA Output
0V
0V
0V
+24
v
+24
v
Span Pot
Zero Pot
Sensor Type Jumper
On = Toxic
Off = Oxygen
Sensor Connection
Sensor Type Jumper
On = Toxic
Off = Oxygen
Test Pot
NC | C | NO
Test Jumper

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Ancillary Equipment:
24V Power Supply (GDP 024-050):
Input Voltage: 100-240V AC 50/60Hz 0.5A
Output Voltage: 24V DC 0.75A mA 18W Max
Connection: Free end wires (3m length)
Operating Temp Range: -10~45℃
Dimension:70*45*30.8mm(L*W*H)
Alarm Flasher & Sounder (AVR20-R/Y):
Intput Voltage: 12-24V DC
Output Specifications: 90 db within 1M at 24V
Connection: Free end wires (150mm black /red)
Operating Temp Range: -10 ~45℃
Enclosure Material: ABS Plastic
IP Rating of enclosure: IP55
Dimension: 122.2*72.8*43mm(L*W*H)
-
+
White Tracer wire = +24V
Unmarked = GND

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Operation:
The 40125 is fully set and up and calibrated when shipped. If the power is connected as
shown the system will function and display the current level of gas which should be zero or
20.9%vol if is an oxygen sensor. The sensor takes approx 30 seconds to reach 10%
operational accuracy and will reach full operational accuracy within 10 minutes of switch on.
The alarm levels are preset in the factory and are shipped with the certificate of calibration,
1. Apply 24V DC to the unit
2. The display will show
3. After a short period (5 seconds) The sensor will enter its operational mode. The
sensor will enter a warm up stage and an alarm may occur but will deactivate as
soon as the sensor has stabilised. (If the sensor has not stabilised after 10 minutes
refer to Calibration part of manual and perform Zero .) The display will then read the
ambient level of gas as shown.
The reading shown is for illustration only this is the normal mode
4. When the detected gas level reaches the preset gas alarm level the display will show.
The LED’s will flash and the Buzzer will sound . Alarm Relay 1 will operate
5. The internal and External Buzzer can be muted by pressing the button on the front
panel .
6. The alarm 1 relay will remain operational until the gas level drops below the alarm
level by an amount of 5% (Hysteresis) or whatever set amount. Relay 1 will then
automatically deactivate
7. The same procedure will occur for alarm level 2. When alarm level 2 is reached and
alarm level 1 has been muted the buzzer will sound, the LED’s will flash and the
external buzzer activate. The Buzzer's can be muted by pressing the MUTE button on
the front panel .
GDA 40125
MODBUS 1.02
CO 0pm
O2 20.9%V
CO 30ppm
Alarm 1
O2 19.5%V
Alarm 1
CO 32ppm
Alarm 1 Mute
O2 19.2%L
Alarm 1 Mute

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8. If the unit looses power the FAULT relay, which is normally activated, will deactivate.
The FAULT relay will also deactivate if the sensor encounters an abnormal condition
or the internal electronics fail
9. Pressing the mute button in any state will not deactivate the alarm relays.
10. 4-20mA o/p
This o/p represents the sensors current o/p of the toxic gasses detected in its
range or the current level of oxygen present. The 40125 can drive into a
maximum loop impedance of 800R. The o/p is NON ISOLATED. Care must be
exercised when 0V referencing the sensor to other apparatus so as not to
inject ground (0V) noise into the 40125. The connecting equipment should
not use an earth tied 0v line. GDA recommends the use of The GD 690
Galvanic isolator in the 4-20mA o/p in safety critical applications
Response time . The sensor is a electrochemical sensor which the Toxic gas or oxygen has to
naturally diffuse into. The sensor response time to gas is <10 seconds. However it may take
longer to diffuse through the sensor and displace all the gas in the electrochemical sensor as
the sensor uses natural diffusion to allow gas into the chamber.
Setup:
ALL systems are factory set up with the sensors ordered and this section will not have to
be followed
To enter setup mode, jumper the right most pins on P7. (On the Setup Option)
Use S1 and S2 to change the setup options. S1 (Top most button) is down while S2 (Bottom
most button) is set.
To change the setting, press the DOWN button, (some settings allow the value to be
incremented by larger steps when the Down button is held for at least 1 second) when the
correct value is indicated press the SET button this saves the selected value to unit and
moves to the next setting option.
If the setup jumper is removed, the current setting will NOT be saved to unit., only pressing
the SET button will save the value If a mistake is made, then removing the jumper will not
save that value.
The setting and its current value is displayed on the screen. During setup no alarms will
sound or relays activated except the Fault relay.
After Setup is complete remove jumper link from board.

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The following numbers show each setting and the values. The default value is shown in bold.
Gas Type:
O2, CO2, CO, Flammable (FLM), H2S, NH3, NO2, Gas, R22, [R]123, [R]134[a], [R]407,
[R]410, Ref
Units:
ppm (pm), % Volume (%V), % Lower Explosive Limit (%L)
Range:
1, 3, 5, 10, 25, 50, 100, 200, 500, 1000, 2000, 5000, 9999
Alarm 1 Type:
Rising, Falling
Alarm 2 Type:
Rising, Falling
Alarm 2 Level can only be set to falling when Alarm 1 is falling. When Alarm 1 is
rising, Alarm 2 cannot be changed from Rising.
Alarm 1 Level:
0-Range (500 steps), 20%V
When the Down button is held, the level will jump 20 steps.
Alarm 2 Level:
0-Range (500 steps), 20 %V
When Alarm 1 is rising, Alarm 2 can only be set to the Alarm 1 level or greater.
When Alarm 2 is falling (and Alarm 1), the Alarm 2 Level must be less than Alarm
level 1.
NOTE: When using default values it is possible to violate the above conditions if the
values are not changed.
When the Down button is held, the level will jump 20 steps.
Alarm Validation Period: (The period the gas has to be present to cause an alarm)
0-250 seconds, 0seconds
When the Down button is held, the level will jump 20 steps.
Alarm Operation:
Latched, Unlatched
Hysteresis:
2%, 5%, 10%, 20%, 40%
Modbus Address:
0-127, 20
When the Down button is held, the address will jump 20 steps.

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Calibration:
The sensor must be fully powered and in a fresh air (21% oxygen balance Nitrogen) for a
minimum of one (1) hour before calibration is carried out.
To enter calibration mode, place jumper link in the left most pins on p7. (on the cal option)
Zero:
THIS MUST BE PERFORMED IN CERTIFIED FRESH AIR. IF ZEROING THE SENSOR
IS NOT PERFORMED IN FRESH AIR THE SENSOR CALIBRATION WILL BE
INVALID AND THE SENSOR READINGS INVALID.
When in calibration mode the value on display is displaying the true value output of the
sensor and should be reading 3.9 to 4.0mA.
If the display is not displaying the 3.9 to 4.0mA adjust the Zero Pot on the back of the unit
until it displays the correct value. DO NOT ALTER THE SPAN POT.
Span:
Spaning of the should be undertaken by PERSONS QUALIFIED BY GDA
Calibration of the sensor should last 6-24 months dependent on environmental conditions
NEVER ALTER THE SPAN POT AS THIS REQUIRES SPECIALISED EQUIPMENT AND WILL EFFECT
THE SENSOR CALIBRATION AND ACCURACY .
***After Calibration or zero is complete remove the CAL jumper link from board.***
THE SENSOR IS FACTORY SET AND WILL NOT REQUIRE ADJUSTMENT PRIOR TO USE .THIS
WORK SHOULD BE UNDERTAKEN BY PERSONS QUALIFIED BY GDA
Calibration
4.0mA
Zero pot
Span pot

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Testing:
The system functionality can be tested without using gas to exercise the sensor unit. This test will
prove the whole system works but will not prove the actual sensor head. The sensor when supplied
comes with a certificate of calibration. The only sure way to test the sensor itself is to expose the
sensor to the target gas.
Testing the system outputs, alarms, sounder and display.
NOTE: if equipment is connected to the any of the o/p devices (relays, 4-20mA o/p, sounder) then
these will activate at the pre-set alarm thresholds. Disconnect any loads that are not to be
activated.
1. Connect the test jumper link as shown
2. Use a screwdriver to turn the test Pot to simulate the sensor output
3. DO NOT ADJUST ANY OTHER POT AS THIS WILL INVALIDATE THE CALIBARTION OF THE
INSTRUMENT.
4. The display will indicate the simulated gas concentration by turning the test Pot.
5. Turn the Pot to activate the relays / sounders and check against gas level displayed on the
display
6. When testing is complete return the test link to the position shown. This is very important.
If this is not undertaken the sensor will not detect gas.

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This product and operating manual are subject to change without prior notice for the improvement
of product performance and ease of use.
Gas Detection (Australia) Pty Ltd
Unit K1, USQ, Baker Street Toowoomba, QLD 4350
PO BOX 597, Darling Heights, QLD 4350 [phone]
www.gasdetectionaustralia.com.au [e-mail]
Thank You for Supporting
Australian Manufacturing