background image

©

 

2008

 

Gastech

 

Australia

 

Pty

 

Ltd

 

 

Page

 

24

     

 

 

3.2.3

 

Sensor

 

Bias

 

Jumper

 

This

 

jumper

 

should

 

be

 

in

 

the

 

off

 

position

 

for

 

all

 

sensors,

 

except

 

sensors

 

needing

 

a

 

Bias

 

voltage.

 

The

 

table

 

below

 

lists

 

some

 

common

 

sensors

 

that

 

require

 

a

 

bias

 

voltage.

 

If

 

you

 

are

 

replacing

 

a

 

sensor

 

for

 

a

 

different

 

gas,

 

the

 

bias

 

voltage

 

may

 

need

 

to

 

be

 

adjusted

 

by

 

the

 

adjustment

 

pot

 

as

 

described

 

next.

 

 

Sensor

 

Model

 

Bias

 

Voltage

 

GasTech

 

Part

 

Number

 

HCL

 

7HL

 

300mV

 

65

8011

7HL

 

NO

 

4NT

 

300mV

 

65

8002

4NT

 

NO

 

7NT

 

300mV

 

65

8002

7NT

 

ETO

 

7ETO

 

300mV

 

65

8013

7ETO

 

HCL

 

3E

 

30

 

200mV

 

65

9097

HCL/HBR

 

NO

 

3E

 

100

 

200mV

 

65

9097

NO

 

THT

 

3E

 

100

 

150mV

 

65

9097

THT

 

 

Inverted

 

signal

 

jumper

 

Jumper

 

in

 

inverted

 

position

 

Summary of Contents for D-Guard

Page 1: ...D Guard TM Digital Guard Intrinsically Safe Intelligent Gas Detector Part Number 65 1010xxx Manual Revision v2 08 updated 5 June 2009 ...

Page 2: ......

Page 3: ...on 22 3 2 1 Isolate Mode 22 3 2 2 Normal Invert Jumper 23 3 2 3 Sensor Bias Jumper 24 3 2 4 Sensor Bias Voltage Adjustment Trimpot 25 3 2 5 Shorting Link Jumper 26 3 2 6 Display Current Calibration Trimpot 27 3 2 7 Oxygen Load Jumper 27 3 3 Software Configuration and Calibration 28 3 3 1 Configuration 28 3 3 2 Calibration 33 APPENDIX I Troubleshooting 38 APPENDIX II Factory Setup 38 3 4 Calibratin...

Page 4: ...es registration in the United States only and the TM is in Australia registrations may not have been issued at present in other countries All other product names and logos are trademarks of their respective owners DISCLAIMER Under no circumstances will GasTech Australia be liable for any claims losses or damages resulting from or arising out of the repair or modification of the equipment by a part...

Page 5: ...eed figure GasTech Australia s policy is to perform all needed repairs to restore the instrument to full operating condition including reactivation or replacement of all out of warranty electrochemical cells original packing and any special instructions Repairs are warranted for 90 days from the date of shipment Sensors have individual warranties Always include your address purchase order number s...

Page 6: ...e TPA implied by Division 2 of Part V of the Act other than that implied by section 69 of the TPA the liability of the Company for such breach shall subject to section 68A 2 of the TPA be limited to one of the following as determined by the Company a the replacement of the Equipment or the supply of equivalent Equipment b the payment of the cost of replacing the Equipment or of acquiring equivalen...

Page 7: ... instructions in this manual particularly those concerning start up operation calibration and maintenance be read understood and followed Notices are used in this operator s manual to alert you to hazardous conditions to person or instrument and to notify you of additional information This operator s manual uses the following notices NOTE Notifies you of additional information CAUTION Notifies you...

Page 8: ...set up and highly stable fixed point toxic and Oxygen gas detector The D GuardTM is an industry standard two wire 24VDC 4 20mA device 1 1 Features Non intrusive calibration No alarms during calibration One PCB card for all gases detected No tool calibration Sensor drift elimination program Long term sensor deteriation drift elimination program Permanent back light Fail safe mode Non corrosive hous...

Page 9: ...he serial number is also on a label on the side of the D Guard TM Please record the serial number on the front of this manual The installation should be in the area with most potential to detect the gas as quickly as possible Take note of the gas density as this will help in finding the best location for the D GuardTM For example heavier gases like H2S would have the sensor mounted lower than for ...

Page 10: ...e 4 housing lid screws 4mm Alan key The screws are held in with O rings to stop them falling out and losing them 2 Gently remove the lid making sure that you don t lose the 4 lid screws or the large O ring that seals the lid to the base 3 Turn over the lid to find the green power connector 4mm Hex or Allan Key screws Screw retaining O ring Power connector ...

Page 11: ...rommet to the green connector as described in the next section 5 Once the wiring is complete confirm that the housing sealing O ring is fitted and in good condition 6 Fit lid and tighten the 4 screws using a 4mm Allan key tightening the housing evenly Housing O ring seal ...

Page 12: ... bottom right corner there is a two pin removable plug Ensure the positive and negative wires are terminated with the correct polarity which is marked on the PCB 2 3 1 Connection to Controller When connecting a D GuardTM unit to a controller such as the GasTech 4100R controller follow the pinouts as outlined below Other third party controllers are also connected in the same manner Removable 2 pin ...

Page 13: ...nt you will need to select an appropriate IS barrier Selection of the type of barrier requires consideration of the voltage drops that occur in the system As the D Guard requires a minimum of 12VDC to operate the voltage drops in the barrier system controller load resistor and cabling cannot exceed the power supply voltage less 12VDC WARNING Installers should consult the Intrinsically Safe Barrier...

Page 14: ...h Australia Pty Ltd Page 12 GasTech recommend the GasTech 57 9010 02 barrier KFD2 STC4 Ex1 for most systems This barrier will work on all controllers at 24VDC Wiring of the GasTech 57 9010 02 barrier is as follows ...

Page 15: ...sed in conjunction with the GasTech 4100R controller card as the 4100R card has 100Ω load WARNING If you use this barrier on another controller that uses a load above 100Ohms the D Guard will turn off when it see a high gas reading 15mA as the volt drop over this barrier is greater Wiring of the GasTech 57 9010 01 barrier is as follows ...

Page 16: ...de of the power supply DG This needs to be connected to the connector on the D GuardTM main PCB DG This needs to be connected to the connector on the D GuardTM main PCB AL1 Low Alarm This relay is energized when AL1 is active This alarm point is adjustable in software as described in the next section AL2 High Alarm This relay is energized when AL2 is active This alarm point is adjustable in softwa...

Page 17: ... can still be connected back to a controller such as the Gastech 4100R The diagram below shows how the units are wired together NOTE In this configuration the jumper on the relay PCB must be removed Internal Connection diagrams REMOVE Lk1 Do not insert Connect to 24VDC Connect to 0VDC D Guard to Relay Board Connections Current loop output configuration Connect to PLC current loop input current sin...

Page 18: ... 2008 Gastech Australia Pty Ltd Page 16 Lk1 MUST BE INSERTED Connect to 24VDC Connect to 0VDC D Guard to Relay Board Connections Standalone configuration ...

Page 19: ... correct 24VDC 5 Turn on the incoming power at the power source NOTE The D GuardTM starts up in a warm up Isolated mode with the mA locked at 3mA for 90 seconds while the sensor stabilised and the D GuardTM program initialises and completes a series of function tests After the start up procedure and all tests are completed if operating is within tolerance the display will go into normal operating ...

Page 20: ... stored in the D GuardTM non volatile memory but as no monitoring of the sensor operation is performed during the shutdown period the sensor might have been poisoned and might not respond as expected 3 1 Changing the PCB or Sensor 1 Isolate the sensor back at the control panel so an open circuit fault will not trip or create any alarms 2 Remove the 4 housing lid screws 4mm Alan key The screws are ...

Page 21: ... connector and the D GuardTM will power down The display will go blank and the back light will turn off 5 Move to a clean location 6 Gently remove the 4 Phillips head screws holding the PCB in place 7 Gently remove the PCB which will expose the sensor Power connector PCB mounting screws ...

Page 22: ...If you are replacing the sensor remove the old sensor and plug in the new one Confirm the new sensor is the same as the old sensor 10 Gently press the new sensor back into place 11 If replacing a sensor you should also replace the sensor filter and gasket at the same time 12 The sensor filter and gasket need to be ordered separately to the sensor Note The sensor filter part number is 33 9998 and t...

Page 23: ... back onto the lid and gently tighten the 4 Phillips head screws until the PCB comes flush with the mounting posts 16 If you have just replaced the PCB or have replaced the sensor with a different model skip to the next section as the PCB may need some jumper or calibration settings changed 17 If you are replacing the sensor with the exact same model as previous the enclosure can be screwed back t...

Page 24: ...me hardware jumpers and trim pots that may need adjustment Before proceeding make sure the sensor is isolated to prevent any false alarms 3 2 1 Isolate Mode The isolate mode of the D GuardTM is a feature which you can isolate the sensor for maintenance or if the sensor has an extended stabilization period First open the calibration plate by unscrewing the two thumb screws on the calibration plate ...

Page 25: ...nsor that has a reducing sensor output Contact the factory for confirmation on the sensor that is being fitted The table below lists some common sensors which require the jumper set to invert mode Gas Sensor Model GasTech Part Number Chlorine 4CL 7CLH 65 8009 4CL 65 8009 7CLH Nitrogen Dioxide 4ND 7NDH 65 8004 4ND 65 8004 7NDH Ozone 7OZ 65 8005 7OZ Chlorine Cl2 3E 10 50 65 9097 CL2 1 65 9097 CL2 2 ...

Page 26: ...oltage If you are replacing a sensor for a different gas the bias voltage may need to be adjusted by the adjustment pot as described next Sensor Model Bias Voltage GasTech Part Number HCL 7HL 300mV 65 8011 7HL NO 4NT 300mV 65 8002 4NT NO 7NT 300mV 65 8002 7NT ETO 7ETO 300mV 65 8013 7ETO HCL 3E 30 200mV 65 9097 HCL HBR NO 3E 100 200mV 65 9097 NO THT 3E 100 150mV 65 9097 THT Inverted signal jumper J...

Page 27: ...g up the board for a different sensor that needs to adjust the bias voltage please contact the factory before hand to confirm the procedure 1 Measure the millivolts across the reference and sensing sockets on the PCB as shown below 2 Adjust the Bias trimpot to the required Bias voltage 3 The Bias jumper must be in the On position and the shorting link must be removed Sensor bias jumper Sensor bias...

Page 28: ...ustralia Pty Ltd Page 26 3 2 5 Shorting Link Jumper The shorting link will be installed on all non bias sensors Sensor Bias voltage adjustment pot Sensing Reference Shorting link jumper Shorting link jumper installed ...

Page 29: ... set and should not need adjusting See the Appendix for more information 3 2 7 Oxygen Load Jumper This jumper is only applicable for an Oxygen sensor It will be in the down position for an Oxygen sensor and up for all other sensors Oxygen load jumper Display current calibration Load jumper in Oxygen mode ...

Page 30: ... calibrated to the sensor you have fitted This is achieved using the 4 buttons on the front panel 1 Power up the D GuardTM Open the calibration plate to enter calibration mode To open the calibration plate unscrew the two thumb screws on the calibration plate Note The plate is designed to pivot on the left screw The screws are different length and will stay connected to the plate The screws are ca...

Page 31: ...p and Down buttons to toggle between the various gases until the matching gas is found Press the Select button to move to the next menu or press and hold the Select button for five seconds to load default calibration values for the selected sensor The default calibration values are shown in the table below GAS FSCALE ALARM1 ALARM2 DP CAL GAS UNITS GAIN CL2 10 0 0 5 1 0 10 0 5 0 ppm 11 SO2 20 0 2 0...

Page 32: ...essing the Select button will move along to the next digit Repeat this procedure until the value is set and then press the Select button to move to the next menu 11 The next screen is used to enable or disable alarms Use the Up or Down button to toggle between on or off Press the Select button to move to the next menu Note Alarms should only be set to ON if the D Guard is being used with the optio...

Page 33: ...used to set the gain for the sensor Use the Up or Down button to set the correct gain value 16 Another way of determining the required gain is to look up the sensor sensitivity output current from the manufacturer s specification datasheet Multiply the sensor output by the range of the detector This will provide you with the Calculated Full Scale Sensor Output Establish the correct gain setting us...

Page 34: ... advanced software monitors the sensor performance and small sensor drifts which is a characteristic of all sensors This drift is due to sudden temperature humidity and pressure changes or aging sensors The advanced electronics and software will remove this insignificant drift and keep the detector reading zero or 20 9 for an Oxygen sensor Use the Up or Down button to toggle between on or off Pres...

Page 35: ...of the detector this is an Australian standard recommendation Other concentrations are useable but using lower concentrations could have an effect on the overall accuracy of the detector Calibration intervals are completely site and local regulations dependant this will vary widely between different countries states and sites safety regulations for fixed gas detection systems The type of sensor wi...

Page 36: ...the sensor installed in your D GuardTM unit 3 3 2 1 Calibrating An Oxygen Sensor 1 Open the calibration plate and the zero calibration menu will be shown as this setting needs to be adjusted first Note Opening the calibration plate will lock the output signal to the mA equivalent of fresh air 20 9 vol O2 This will prevent any alarms being generated when calibrating the D GuardTM 2 When adjusting t...

Page 37: ... for 120 seconds 5 Use the Up and Down buttons to adjust the reading to the calibration gas value This is normally 0 0 when using pure nitrogen or 18 0 when using a 4 gas mixture containing 18 0 O2 6 You can also press both the Up and Down buttons together to activate an automatic zero adjustment Press the Select button to move to the next menu Note The highlighted zero value indicates the relativ...

Page 38: ...calibration plate and the zero calibration menu will be shown as this setting needs to be adjusted first Note Opening the calibration plate will lock the mA output signal at 4mA zero This will prevent any alarms being generated when calibrating the D GuardTM 2 With the sensor in a clean gas free environment no target gas present you can use the Up or Down button to adjust the gas reading to 0 3 If...

Page 39: ...highlighted span value indicates the relative position of the span adjustment where 0 is the minimum and 255 is the maximum 10 Once the calibration is completed remove the gas and allow the sensor to come back to Zero or below the low alarm level before closing the calibration door Closing the calibration door before the sensor has returned to Zero will release the mA signal and could cause an ala...

Page 40: ...r 2 If you get the following message on the screen SENSORFAIL This is due to the sensor signal is too week or two strong 3 Replace sensor Sensor unstable readings 1 Check gain setting on sensor as a too high gain setting can result in unstable reading 2 Replace sensor APPENDIX II Factory Setup Note Before proceeding with any steps in this section isolate the sensor back at the controller so the D ...

Page 41: ...asily measured using a multimeter on millivolts setting across test points TP1 and TP2 shown below This allows the output to be calibrated without disconnecting the D GuardTM from the loop Note These two test points have a 10Ω resistor between them so measuring the voltage access these points divided by 10 will give the current draw of the unit 6 Press the Up or Down buttons until the multimeter r...

Page 42: ...it 9 Adjust the trimpot shown below until the reading on the multimeter shows exactly 200 000mV This means that the unit is correctly set to 20 00mA at the full scale point 10 Once any adjustments have been made remove the jumper between pins 1 and 2 screw the lid back together close the calibration door and normal operation will resume Full scale adjustment ...

Page 43: ...atus D Guard Gas Detector Optional accessory Type of Protection Ex ia IIC T4 Ta 55 degree C IP66 Marking GasTech Australia Pty Ltd D Guard Gas Detector IECEx TSA 07 0003X Ex ia IIC T4 Ta 55 degree C IP66 Ui 30V Ii 95mA Ii cont 86 8mA Pi 0 7W Ci 36 3nF Li Negligible Serial no Approved for issue on behalf of the IECEx Certification Body Ujen Singh Position Quality Certification Manager Signature for...

Page 44: ...requirements This certificate is granted subject to the conditions as set out in IECEx Scheme Rules IECEx 02 and Operational Documents as amended STANDARDS The electrical apparatus and any acceptable variations to it specified in the schedule of this certificate and the identified documents was found to comply with the following standards IEC 60079 0 2004 Edition 4 0 Electrical apparatus for explo...

Page 45: ...d Gas Detector is a toxic and oxygen gas detector with graphic LCD display and using the industry standard 24V 4 20mA 2 wire interface It is to be installed behind an intrinsic safety barrier It uses the 4 series and the 7 series range of toxic and oxygen electro chemical sensors CONDITIONS OF CERTIFICATION YES as shown below Refer to the Conditions of Certification in attached Annexe for IECEx TS...

Page 46: ...inless Steel 8 1 10 1010 04 Screw Captive Panel Thumbscrew Cal Plate D GuardTM 10mm Long Stainless Steel 9 1 10 1010 05 Screw Captive Panel Thumbscrew Cal Plate D GuardTM 17 5mm Long Stainless Steel 10 1 18 7000 Cable Gland non EXD 65 S and D GuardTM 11 1 21 1010 Housing Top and Bottom D GuardTM 12 1 21 1010 01 Splash Guard D GuardTM 13 1 21 1010 02 Calibration Plate D GuardTM 14 1 29 1010 01 Deca...

Page 47: ... range of the O2 sensor 30 minutes time out if door is not closed after calibration or no inputs are seen for 30 minutes If longer is needed use the isolate switch Isolate Isolate switch will isolate the output to 3mA until the switch is reactivated Operating temperature 20 to 55 C Operating humidity 0 to 95 RH non condensing Dimensions 160mm x 273 x 92mm Including standard cable gland and mountin...

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