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GDS GDS-68XP User Manual

1. Trip On High On Delay 0 Off Delay 0 Deadband 196 Alarm 2 Setpoint 50 0 No alarms from channel 1 Latching No Trip On High On Delay 0 Off Delay 0 Deadband 196 Alarm 3 Enabled NO No alarms from channel 1 Setpoint 50 0 Latching No Trip On High On Delay 0 Off Delay 0 Deadband 196 Fault Alarm Setpoint 10 of scale Fault alarm always enabled Data From Sensor Type EC Sensor Min Raw 800 Max Raw 4000 Filter Samples 60 Polarity POS PGA Gain Sensor Specific GAIN determined by sensor Heater Enabled No Heat degC 10 00 Local Cal Yes Temp Comp 40 Gain Offset 1 00 0 00 30 Gain Offset 1 00 0 00 Page 60 GDS 68XP Operation amp Maintenance Manual Revision 3 4 20 Gain Offset 1 00 0 00 10 Gain Offset 1 00 0 00 0 Gain Offset 1 00 0 00 10 Gain Offset 1 00 0 00 20 Gain Offset 1 00 0 00 30 Gain Offset 1 00 0 00 40 Gain Offset 1 00 0 00 50 Gain Offset 1 00 0 00 Configure Tag Name Raw Sensor Eunits mg m3 Zero 0 Span 50 Decimal Points 0 Channel On Yes Deadband 196 In Cal mA 1 5 mA Backup Restore N A Calibrate Offset Sensor Specific Calculated by calibration procedure Gain Sensor Specific Calculated by calibration procedure
2. 008 2 vOrp Gas and Flame Detection Operation and Maintenance Manual GDS 68XP Process Monitor for Low O Applications AUTHORIZED DISTRIBUTOR GasDetectorsUSA com Houston Texas USA sales GasDetectorsUSA com 832 615 3588 GDS 68XP Operation amp Maintenance Manual Revision 3 4 CAUTION FOR SAFETY REASONS THIS EQUIPMENT MUST BE OPERATED AND SERVICED BY QUALIFIED PERSONNEL ONLY READ AND UNDERSTAND INSTRUCTION MANUAL COMPLETELY BEFORE OPERATING OR SERVICING ATTENTION POUR DES RAISONS DE S CURIT CET QUIPEMENT DOIT TRE UTILIS ENTRETENU ET R PAR UNIQUEMENT PAR UN PERSONNEL QUALIFI TUDIER LE MANUE D INSTRUCTIONS EN ENTIER AVANT D UTILISER D ENTRETENIR OU DE R PARER L QUIPEMENT REVISION HISTORY Revision 3 0 6 5 13 Initial rewrite for version 3 0 Revision 3 1 11 1 13 Update for GASMAX CX Revision 3 2 12 15 13 Update for v2 3 sequencer firmware Revision 3 4 1 30 14 Update for v2 4x sequencer firmware Copyright 2014 GDS Corp All Rights Reserved P N 1200 0732 05 Page 2 GDS 68XP Operation amp Maintenance Manual Revision 3 4 1 SAFETY INFORMATION 2 GENERAL INFORMATION Introduction Explosion Proof Installation Intrinsically Safe Installation 3 SPECIFICATIONS 4 OPERATION Overview Sample Draw Configuration Sensor Considerations 5 INSTALLATION Selecting a Location Power amp Signal Connections On Demand Sequence Input Ethernet Connection Relay Con
3. 24VDC 24VDC Common from GASMAX 2 Out Ch 2 In GND 14 Pin Ribbon Cable 14 Pin Ribbon Cable I HERMES 0000000 21 GASMAX DISPLAY Backside PUMP VALVE PCB SENSOR HEAD Figure 14 1 GDS 68XP Wiring Diagram Page 58 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Values shown are for units configured for a range of 0 50 mg m3 For alternative ranges modify the SPAN ENGINEERING UNITS CAL SPAN VALUE and ALARM LEVEL settings as necessary Menu Setting Value Comment or Customer Setting Alarm Outputs Menu OK Relay 1 Alarm 1 Ch2 Alarm 2 Off Alarm 3 Off Fault Off Acknowledge No Failsafe No Override None Relay 2 Alarm 1 Off Alarm 2 Ch2 Alarm 3 Off Fault Off Acknowledge No Failsafe No Override None Relay 3 Alarm 1 Off Alarm 2 Off Alarm 3 Ch2 Fault Off Acknowledge No Failsafe No Override None Channel Settings Menu OK Channel 1 Alarm 1 Setpoint 50 0 No alarms from channel 1 Latching No Page 59 GDS 68XP Operation amp Maintenance Manual Revision 3 4
4. Purge Air Inlet m d 1 1 preces 1 TI Flow Switch Purge Air Pump Sensor Flow Cell os Sample Outlet Sample Inlet gt Run Cal Valve Flow Meter Filter Cal Gas Inlet Figure 4 4 GDS 68XP Flow Diagram Sample Draw SENSOR CONSIDERATIONS The GDS 68XP supports electrochemical sensors for hydrogen sulfide THT and mercaptan Each sensor contains a fixed amount of chemical electrolyte that reacts with the target gas to create free electrons that are amplified and measured Once the electrolyte is depleted sensor output will diminish and the sensor must be replaced IMPORTANT TOXIC SENSORS ARE SUBJECT TO ACCELERATED DETERIORATION IF POWER IS NOT APPLIED WITHIN 3 MONTHS OF SHIPMENT FROM GDS CORP Page 14 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SELECTING A LOCATION Locate the GDS 68XP as close as practical to the source of the sample gas to minimize latency and ensure that fresh sample is available for each sequence The GDS 68XP plate and or enclosure feature mounting holes that can be used to securely attach the monitor to a bulkhead or wall Make sure there is sufficient clearance below and to the left side of the GDS 68XP to allow room for power amp signal cables purge air sample filter bypass if installed filter drain and sample exhaust tubing If the unit is installed outside or where insects or dust may be present be sure that the suppli
5. PGA Gain sets the analog amplification level in the smart sensor interface circuit WARNING Changing PGA gain resets calibration data Heater Enabled Determines if the internal sensor heater is ON or OFF Heat degC Heater thermostat setting Figure 9 3 Channel Settings Menu Tree 1 Page 37 Temp Gain Offset 40 0 30 0 0 0 0 0 0 0 0 0 PRP PRP Configure Hydrogen sulfide E Units 2 5 Zero 0 00 Span 100 0 Decimal Points 0 Channel Yes Deadband 0 00 Backup Restore gt Calibrate Offset 1878 Gain 1 00 Cal Zero 0 00 Cal Span 100 0 Set Unity Gain GDS 68XP Operation amp Maintenance Manual Revision 3 4 Temperature Compensation compensates for changes in sensor output gain and zero value offset as sensor temperature changes Individual values for gain and offset can be entered for eleven points ranging from minus 40C to 60C Gain and offset values are linearly interpolated between points by the internal microprocessor NOTE These values are typically set by the sensor manufacturer and should not be changed Configure Menu Measurement Name User programmable character string to describe the channel Otherwise called tag name E Units User programmable character string that describes the engineering units value Zero Channel zero value typically 0 Span Channel full scale
6. Resets number of network errors to zero Figure 9 5 Comm Settings Menu Page 39 SYSTEM SETTINGS MENU GDS 68XP Operation amp Maintenance Manual Revision 3 4 The Comm Settings Menu allows the user to configure the Ethernet interface MODBUS TCP slave and two optional RS 485 serial interfaces System Version Configure v1 00 Digital Input View Event Log Clear Event Log gt View Sensor Life Configure Unit 44 1000 Date 01 25 2013 Time 04 33 05 Warmup m 1 Cal Purge m Block Neg No Send SensrLife No Incal mA 0 00 Alm Refresh m 0 Digital Input Mode Flt Override Normal ly Open Channel ch 1 amp 2 Hh mm Ch Event 01 25 2013 03 35 2 Fault Out 03 34 2 Fault In 03 33 2 Fault Out 03 32 2 Fault In Ch 1 Sensr Found Life 10096 Ch 2 No Sensor Configure Menu Date amp Time Sets the system date and time Used for display and event log entries Warm Up Delay Sets length of time in minutes from power on to output signals active During Warmup Delay the 4 20mA outputs set to 4mA Cal Purge Delay Sets length of time in minutes that outputs are disabled following a zero or span calibration Block Negative If YES blocks screen from showing negative values Send Sensor Life If YES enables transmission of sensor life data across 4 20 output see GASMAX CX manual for more details InCal mA Sets the 4 20mA output value to be transmitted dur
7. air flow Page 20 GDS 68XP Operation amp Maintenance Manual Revision 3 4 FILTER DRAIN amp FILTER BYPASS All GDS 68XP configurations include a coalescing filter with stainless steel drain valve For positive pressure models the drain valve should be opened periodically to release any built up liquid that may have been trapped inside the filter Conversely the filter drain valve may be left cracked open to allow moisture and sample gas to escape on a continuous basis Models with the combination coalescing and membrane filter include a bypass valve that should be opened slightly to maintain a constant flow of sample across the membrane element to carry away moisture and particulates captured by the filter Filter Drain Recommendations 1 Including a length of clear tubing in the filter drain line makes it easy to monitor the drain for the presence of moisture 2 Filter drain and filter bypass drain can be combined in the same manifold 3 Filters in sample draw units should only be drained during sample purge or purge hold times to keep ambient air from being drawn into the GDS 68XP by the sample pump IMPORTANT DO NOT TIE SAMPLE EXHAUST TO A COMMON EXHAUST MANIFOLD MAINTAIN A SEPARATE SAMPLE EXHAUST LINE TO AMBIENT AIR Filter i Sample Exhaust IMPORTANT M
8. 10 0205 Flow Meter Filter Element 10 xxxx Figure 12 1 GDS 68XP Sample Draw Coalescing Filter Spare Parts Page 52 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Sequencer Assembly Sequencer Actuators 20 0057 Sequencer processor PCB 1200 0234 Sample Pump 20 0058 Sequencer actuators PCB includes 1200 0047 Flow Switch pump flow switch and 3 way valve 1200 0034 3 valve 1200 0034 Flame Arrestors 3 Display 10 0387 1 0 Board 10 0390 Optional Relays amp 10 0388 Sensor Head 10 0247 Flow Cell 10 0205 Filter 1200 0037 1200 0056 10 0205 Run Cal Valve Flow Meter Filter Element 10 xxxx Figure 12 2 GDS 68XP Low Pressure Coalescing Filter Spare Parts Page 53 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Sequencer Assembly Sequencer Actuators 20 0057 Sequencer processor PCB 1200 0234 Sample Pump 20 0058 Sequencer actuators PCB includes 1200 0047 Flow Switch pump flow switch and 3 way valve 1200 0034 3 valve 1200 0034 Flame Arrestors 3 Display 10 0387 1 0 Board 10 0390 Optional Relays amp MB 10 0388 Sensor Head 10 0247 Flow Cell 10 0205 Filter 1200 0037 1200 0056 10 0205 Run Cal Valve Flow Meter Filter Element 10 Figure 12 3 GDS 68XP High Pressure Coalescing Filter Spare Parts Page 54 GDS 68XP Operation
9. Alarm 2 Alarm 3 Fault Alarm Data From Temp Comp Configure Calibrate All three relay outputs are identical and can be set to respond to channel 1 or channel Alarm X menu all three alarm setting menus are identical Set Point is the engineering unit value where the alarm trips It may be negative or positive Latching YES causes the alarm to remain active even after the event clears NO clears the alarm automatically Trip On HIGH causes the alarm to activate if the value goes above the Alarm x Setpoint 20 00 Latching NO Trip On High setpoint Trip On LOW activates the alarm if the value goes below the setpoint Fault Off On Off Delay adjusts the time delay between the time when the event On Delay sec 0 Off Delay min 0 Dead Band al occurs and when the alarm is activated Deadband prevents alarm cycling when the value is close to the alarm level Fault Alarm Setpoint 10 00 Fault Alarm setpoint is typically set at 10 of full scale Data From Data From Menu EC Sensor Remote Sensor No Min Raw 800 Max Raw 4000 Filter Samples 20 Polarity POS PGA Gain gt Heater Enabled No Heat degc 10 0 Data From determines the source of the data for this channel Min Raw Max Raw Set the range of the input A D converter Normally set to 800 min and 4000 max Useful if a sensor s output does not provide a full range signal Filter Samples Number of samples used by the smoothing filter
10. FLOW METER ALLOW THE READING TO STABILIZE AND PRESS THE EDIT KEY TO ACCEPT THE CURRENT READING AS SPAN PRESSING BYPASS ALLOWS TARGET GAS TO FLOW THROUGH THE SEQUENCER ALLOW THE GAS TO FLOW FOR ABOUT AS LONG AS IT DOES DURING A NORMAL SEQUENCE USUALLY BETWEEN THREE AND FOUR MINUTES IF SPAN READING IS WITHIN LIMITS THE SPAN CAL SUCCESS SCREEN WILL MOMENTARILY APPEAR THE GASMAX DUAL SCREEN WILL REAPPEAR SHOWING CHANNEL 1 IN PURPLE CAL DELAY COMPLETE CALIBRATION PRESS RUN ON THE SEQUENCER AND DISCONNECT THE SPAN GAS CYLINDER ONCE CAL PURGE DELAY IS COMPLETE THE SEQUENCER WILL RETURN TO THE PURGE HOLD MODE Figure 7 3 Calibration Procedure Sample Stream Page 31 GDS 68XP Operation amp Maintenance Manual Revision 3 4 NORMAL OPERATION Once setup is complete user intervention is not required and the GDS 68XP automatically measures and outputs the gas concentration value on an interval set by the sequence switch When the GDS 68XP is running a sample sequence the red LED L1 will be flashing Do not attempt to adjust any settings or perform a calibration during a sample sequence A complete sequence usually takes between 10 and 15 minutes to complete To determine the current status of the sequence count the number of L1 flashes and refer to Figure 6 3 During purge hold mode the green LED L2 will be flashing the gas detector can be calibrated and the sequence
11. Larger diameter tubing should be avoided due to the internal volume of entrained gas Max 60 Feet With OD Tubing gt Inlet Delay Calculation For OD stainless steel tubing allow 5 seconds delay for every 10 feet of sample line Mount GDS 68XP above sample point if possible es mm Figure 5 6 Inlet Tubing Recommendations In the event that the GDS 68XP must be mounted at a greater distance from the sample pickup point the combination coalescing bypass filter is recommended This filter includes a bypass port and bypass valve that can be slightly to enable continuous flow of sample from the pickup point to the filter input ensuring that fresh sample is always available IMPORTANT WHEN CONFIGURED FOR SAMPLE DRAW THE GDS 68XP SAMPLE PUMP IS CAPABLE OF PULLING UP TO 7 0 PSI VACUUM ENOUGH TO WATER OVER 15 FEET CARE SHOULD BE TAKEN TO SUBMERGE THE SAMPLE PICKUP POINT IN LIQUID INJESTED LIQUID IS NOT COVERED UNDER WARRANTY If a unit that has been configured for sample draw is connected to a sample source with pressure higher than ambient an additional low pressure regulator or flow restriction device should be installed in the sample inlet line before the GDS 68XP This will allow the sample flow to be adjusted to match the purge
12. mode during which purge air is periodically passed across the sensor to prepare it for the next sequence The length of the Purge Hold time is determined by the SEQUENCE switch setting Condition Charge Recovery Sensor Delay Read Purge Hold New Cycle I i e eS ip OM RAW SENSOR Value or Fault indication transferred to Output Figure 4 2 GDS 68XP Sample Timing GDS 68XP Sequence Timing Condition Fixed Sample Sample Sensor Purge Hold Sensor Delay Charge Read Recovery Valve opens Purge air Valve opens Sequencer finds Purge air applied Purge air applied sample flows applied to sample flows and stores max to sensor until to sensor to sensor sensor to sensor gas reading output lt 10 of intermittent valve closes scale Fixed 5 10 Fixed 5 Two minutes Min 2seconds Min 1 second Determined by seconds minutes or value gt 25 5 minutes Max 10 minutes Sequence switch Figure 4 3 GDS 68XP Maximum Timing Values Page 13 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SAMPLE DRAW CONFIGURATION In addition to low and high positive pressure versions the GDS 68XP can be configured to draw a sample from ambient pressure sources In this configuration the pump operates continuously to pull from both purge air and sample sources See Fig 4 4
13. 67 22 5 FAULT SENSOR INPUT gt 10 OR 1096 OF SCALE AT START OF CYCLE SENSOR FAULT SENSOR BAD OR IN FAULT 2596 0 0 MA 0 75 4 25 Figure 8 1 Fault Conditions Page 33 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SENSOR REPLACEMENT If a sensor shows FAULT does not respond to gas or can no longer be calibrated it should be replaced Use type 10 98XX Ryyyy sensors where the XX is gas type Fig 3 1 and is range 25 0025 Doll Page 34 Step 1 Turn off DC power Step 2 Disconnect the sample inlet tube at the sensor flow cell Step 3 Disconnect the sample exhaust tube at the flow cell Step 4 Unscrew the sensor flow cell and sensor head cover Step 5 Pull straight down to remove the existing sensor Step 6 Compare the new sensor with the old sensor and verify identical part numbers Step 7 Install the new sensor by aligning the arrow on the sensor with the arrow on the sensor hea
14. Manual Revision 3 4 INTRODUCTION The GDS 68XP provides a safe and reliable way to measure the level of hydrogen sulfide mercaptan THT and other gases in a process stream that contains low levels of oxygen The GDS 68XP uses a programmed sequencer to alternatively apply sample and purge air to a highly sensitive and reliable electrochemical sensor Applying purge air periodically refreshes the sensor s chemistry significantly extends the life of the sensor and reduces the total amount of sample gas released into the atmosphere The GDS 68XP can be configured to draw samples from non pressurized ambient sources or to accept positive pressure samples from 5 psig to 1500 psig Multiple filter options are available and the unit features a low flow warning switch and long life brushless DC pump for sample and purge air The GDS 68XP features the new dual channel GASMAX CX networked gas monitor In addition to a new high visibility color display the GASMAX CX includes an Ethernet port with built in MODBUS TCP interface and web server for complete integration into user networks GDS Corp software can be used to remotely monitor the status and performance of GDS 68XP systems if a network connection is available EXPLOSION PROOF INSTALLATION The GDS 68XP is designed for use in Class 1 Division 1 hazardous areas Installation in these areas should follow best industry standard practices
15. OFF ON ON RAW SENSOR INPUT TO CHANNEL 1 CAL MODE SLOW FLASH OFF ON OFF PURGE AIR FLOWING TO SENSOR 1 Pump is ON if sample draw OFF if positive pressure 2 Pumpruns intermittently 3 15 minute warm up starts once sensor output reaches stable value 1096 of scale Figure 6 3 L1 L2 Indicator Operation Page 25 GDS 68XP Operation amp Maintenance Manual Revision 3 4 GASMAX CONTROLS AND DISPLAY There are four magnetic switches on the face of the GASMAX CX arranged in a quadrant around the LCD display Starting in the upper left and proceeding clockwise these are labeled UP NEXT EDIT and DN CAL To activate or press a magnetic switch swipe the magnet near the switch For the balance of this manual the term press will be used to describe activation of any key via the magnetic wand Below the LCD display two LEDs monitor the MODBUS RS 485 or Ethernet network interface Flashing indicates sent or received data The EDIT key activates the USER MENU mode See Chapter 8 During USER MENU mode the UP DN and NEXT keys are used to select and confirm menu entries The USER MENU allows the operator to view the Event Log and channel parameters and change system settings such as alarm levels and real time clock day and date Pressing the DOWN CAL key followed by the EDIT key initiates calibration mode For a detailed description of calibration see Chapter 6 Pressing the NEXT key
16. Points 0 Channel On Yes Deadband 196 In Cal mA 3 0 Comm Settings Menu OK Comm 1 Type MB Slave Programmed by user Baud Rate 9600 Parity None Timeout 500 Poll Delay 250 Byte Order BADC Enable LEDs No Comm 2 Type MB Slave Programmed by user Baud Rate 9600 Parity None Timeout 500 Poll Delay 250 Byte Order BADC Enable LEDs No MODBUS TCP Slave Programmed by user Byte Order BADC Master Timeout 500 Poll Delay 250 Enable LEDs Yes GDS 68XP Operation amp Maintenance Manual Revision 3 4 Network Settings DHCP Enabled Yes Programmed by user Hostname GDS 68XP IP Address N A Netmask N A Gateway N A Security Menu OK Lock Code Lv Factory default MB Web Code 1234 Contact Info Default System Menu OK Version 1 0 Configure System name GDS68XP Programmed by user Date Date Set today s date Time Time Set current time Warmup m 1 Cal Purge m 1 Block Negative No Send Sensor Life No Alarm Refresh 0 Digital Input Mode Alarm Reset Event Log Clear event log View Sensor Life N A Page 64 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Earlier versions of the GDS 68XP sequencer board utilized a DIP SWITCH to set sequence timing values For reference the settings found in earlier units are shown below Sequence DIP SWIT
17. TO STABILIZE AND PRESS THE EDIT KEY TO ACCEPT THE CURRENT READING AS ZERO IF THERE IS A POSSIBILITY THAT TARGET GAS MAY BE PRESENT IN AMBIENT AIR USE CYLINDER OF ZERO AIR IN PLACE OF PURGE AIR IF ZERO READING IS WITHIN LIMITS THE ZERO CAL SUCCESS SCREEN WILL MOMENTARILY APPEAR THE APPLY SPAN GAS SCREEN WILL APPEAR SET THE SPAN VALUE CONNECT THE SPAN GAS AS SHOWN ABOVE AND TURN ON THE REGULATOR PRESS BYPASS ON THE SEQUENCER AND VERIFY FLOW ON THE FLOW METER ALLOW THE READING TO STABILIZE AND PRESS THE EDIT KEY TO ACCEPT THE CURRENT READING AS SPAN PRESSING BYPASS ALLOWS CAL GAS TO FLOW THROUGH THE SEQUENCER ALLOW THE GAS TO FLOW FOR ABOUT AS LONG AS IT DOES DURING A NORMAL SEQUENCE USUALLY BETWEEN THREE AND FOUR MINUTES IF SPAN READING IS WITHIN LIMITS THE SPAN CAL SUCCESS SCREEN WILL MOMENTARILY APPEAR THE GASMAX DUAL SCREEN WILL REAPPEAR SHOWING CHANNEL 1 IN PURPLE CAL DELAY COMPLETE CALIBRATION PRESS RUN ON THE SEQUENCER AND DISCONNECT THE SPAN GAS CYLINDER ONCE CAL PURGE DELAY IS COMPLETE THE SEQUENCER WILL RETURN TO THE PURGE HOLD MODE Figure 7 2 Calibration Procedure Inlet Port Page 30 GDS 68XP Operation amp Maintenance Manual Revision 3 4 CALIBRATION PROCEDURE STREAM SAMPLE In certain situations calibration gas may not be available However in some cases the target gas value may be known either from lab tests pull tu
18. amp Maintenance Manual Revision 3 4 Sequencer Assembly Sequencer Actuators 20 0057 Sequencer processor PCB 1200 0234 Sample Pump 20 0058 Sequencer actuators PCB includes 1200 0047 Flow Switch pump flow switch and 3 way valve 1200 0034 3 valve 1200 0034 Flame Arrestors 3 Display 10 0387 1 0 Board 10 0390 Optional Relays amp MB 10 0388 Sensor Head 10 0247 Flow Cell 10 0205 Filter 1200 0037 1200 0056 10 0205 Run Cal Valve Flow Meter Filter Element 10 xxxx Figure 12 4 GDS 68XP High Pressure Bypass Filter Spare Parts Page 55 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Sensor Head Assembly 10 0247 lt _ lt Sensor Head Base Sensor 10 98 RYYYY lt Sensor Head Cover Figure 12 5 GDS 68XP Sensor Head Exploded View Page 56 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Li 25 6 i 10 4 25 6 Figure 13 1 GDS 68XP Dimensions NEMA 4X Enclosure Page 57 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Electrical GASMAX BOARD B to GASMAX 4 20 In SEQUENCER PCB tom asuax Qr
19. time can be adjusted To change the sequence time refer to Figure 3 2 and modify the SEQUENCE SWITCH setting as desired Changing the sequence switch will not change the current delay time but will set the delay for the next scheduled sample cycle If it is desired to start a new cycle immediately change the switch setting and then press and hold the RUN button for five seconds COLD WEATHER OPERATION The GDS 68XP is designed for accurate and reliable operation across a wide range of operating conditions Once running the GDS 68XP generates sufficient heat to maintain operation to 0 F ambient However if the unit has been powered off care should be taken during startup to make sure the purge air pump temperature is above 32 F prior to the application of DC power To reduce the possibility of pump damage in extremely cold weather GDS Corp recommends the 200W AC heater be turned on for several hours prior to applying DC power to the system In addition if the unit is to be left unpowered during extremely cold weather GDS Corp recommends the sensor be removed and stored in a warm location NORMAL MAINTENANCE Standard maintenance for the GDS 68XP consists of periodic checks on flow settings and sensor calibration Each time a toxic sensor is calibrated a Sensor Life reading will appear that gives an approximate indication of the remaining sensitivity Sensor Life is not necessarily linear and a rapid reduction in the senor life reading can
20. 18 FIGURE 5 5 200W AC HEATER WIRING 5 1 retire itor EET ane des prete See Tee Perder eng 19 FIGURE 5 6 INLET TUBING 5 nennen nennen nenne nennen 20 FIGURE 5 7 FILTER DRAIN amp EXHAUST TUBING RECOMMENDATIONS eene 21 FIGURE 5 8 GDS 68XP EXHAUST TUBING 2 ore tre t nere hot rp e lieu 22 FIGURE 6 1 GDS 68XP USER INTERFACE perterrita dno green nf 24 FIGURE 6 2 SEQUENCE TIMING vices eere ene toe eee eoe eter eet eee e oie ee ee eed 25 FIGURE 6 3 L1 L2 INDICATOR 2 25 FIGURE 6 4 GDS 68XP GASMAX DISPLAY SEQUENCE 01 mene 26 FIGURE 7 1 CALIBRATION PROCEDURE CAL 29 FIGURE 7 2 CALIBRATION PROCEDURE INLET 30 FIGURE 7 3 CALIBRATION PROCEDURE SAMPLE 5 nennen 31 FIGURE 8 1 FAULT CONDITIONS 4 23 casas tete etr Ue matt te ux EE ORE 33 FIGURE9 1 MAIN MENU TREE et enti etae ast be Ee NR ee ra bea siae RA EA TURA 35 FIGURE 9 2 ALARM OUTPUTS MENU TREE 4444 1100 36 FIGURE 9 3 CHANNEL SETTINGS MENU TREE 1 37 FIGURE 9 4 CHANNEL SETTINGS MENU TREE 2 38 FIGURE 9 5 COMM SETTINGS MENU ne ne ett tate rhet err e e e estie 39 FIGUR
21. 4hours Figure 3 1 Toxic Sensor Characteristics SEQUENCE Sequence Purge Hold Total Cycle Time Switch Time Time Approximate 0 On Demand Sequence 1 hour 12 15 min 40 min 1 hour 2 12 15 min 105 min 2 hours 3 12 15 min 165 min 3 hours 4 12 15 min 225 min 4 hours 5 12 15 min 285 min 5 hours 6 12 15 min 345 min 6 hours 7 12 15 min 465 min 8 hours Figure 3 2 Sequence Timing RECOMMENDED MINIMUM SAMPLE SEQUENCE TIMES GAS TYPE MINIMUM COMMENTS 15 HYDROGEN SULFIDE LOW RANGE 50 PPM 1 HOUR FOR MAXIMUM SENSOR LIFE USE LONGEST POSSIBLE SEQUENCE 15 HYDROGEN SULFIDE 500 PPM 2 HOURS FOR MAXIMUM SENSOR LIFE USE LONGEST POSSIBLE SEQUENCE 31 TETRAHYDROTHIOPHENE 0 50 MG M3 2 HOURS TWO HOURS IS REQUIRED FOR COMPLETE SENSOR RECOVERY FROM METHANE 30 MERCAPTAN 0 50 MG M3 OR 0 3 LB MCF 4 HOURS FOUR HOURS IS REQUIRED FOR COMPLETE SENSOR RECOVERY FROM METHANE 40 GENERAL ODORANTS INCLUDING SPOTLEAK 2 HOURS TWO HOURS IS REQUIRED FOR COMPLETE 41 SENSOR RECOVERY FROM METHANE Figure 3 3 Recommended Minimum Sequence Times Page 11 GDS 68XP Operation amp Maintenance Manual Revision 3 4 OVERVIEW The GDS 68XP uses low cost reliable electrochemical sensors to detect hydrogen sulfide mercaptan THT and other trace gases in process streams that contain little or no oxygen As electrochemical sensors require oxygen to operate the GDS 68XP alternatively exposes the sensor to the process flow and then purges the sens
22. 68XP will enter a hold mode until an external contact closure between J6 1 and J6 2 occurs This causes the GDS 68XP to perform a single sample sequence Upon completion the DONE output will be pulled low to signal the remote controller that the sequence is complete J6 1 START Ground to Common to initiate sequence J6 2 Common J6 3 DONE Open Collector Output pulled low when sequence complete 00000 Access to optional Alarm Relays MODBUS serial ports and Ethernet is via NPT fitting on right side of J1 1 24VDC Power Input 1 2 4 20mA Analog Out 3 Power Signal Common Figure 5 2 GDS 68XP Power and Signal Wiring ETHERNET CONNECTION The GASMAX CX gas monitor includes a standard RJ 45 Ethernet connection on the main 1 board Both fixed IP and DHCP based dynamic IP addressing is supported The GASMAX CX supports a full range of MODBUS TCP accessible register see Chapter 10 as well as a built in web server with data display and gas detector configuration page Page 16 GDS 68XP Operation amp Maintenance Manual Revision 3 4 RELAY CONNECTIONS OPTIONAL The optional GASMAX CX Relay dual MODBUS RTU slave interface is connected piggyback to the back of the GASMAX CX Display Assembly and supplies three level alarm relays FAULT relay and dual RS 485 M
23. AKES SURE SAMPLE EXHAUST IS DIRECTED TO A SAFE AREA Figure 5 7 Filter Drain amp Exhaust Tubing Recommendations NOTE LEAVING THE FILTER DRAIN VALVE CRACKED OPEN WILL ALLOW SAMPLE GAS TO FLOW FROM THE PICKUP POINT TO THE GDS 68XP ON A CONTINUOUS BASIS ENSURING THAT FRESH SAMPLE IS ALWAYS AVAILABLE AT THE BEGINNING OF EACH NEW SAMPLE SEQUENCE Page 21 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SAMPLE EXHAUST Changes in ambient pressure will affect the output from all electrochemical sensors and allowing the sample to exhaust directly to atmosphere will minimize these affects Long runs of tubing connected to the sample outlet may increase the backpressure inside the sensor flow cell and cause higher than normal readings Hydrogen sulfide is a heavy gas and will tend to back up inside sample exhaust lines that extend vertically for too great a distance Sample Release to Atmosphere Remember that sample exhaust is only released to the atmosphere during sample measurement time not continuously 15 5m maximum Maximum Rise Limit the vertical exhaust to a point no greater than 15 feet above the top of the GDS 68XP Figure 5 8 GDS 68XP Exhaust Tubing IMPORTANT DO NOT RESTRICT SAMPLE EXHAUST OUTLET PRESSURE IN THE SAMPLE FLOW CELL MAY DAMAGE THE SENSOR AND WILL RESULT IN INCORRECT READINGS IMPORTANT WHEN INSTALLING THE GDS 68XP OUTDOORS MAKE SURE SAMPLE EXHAUST IS PROTEC
24. ATION ON RAW SENSOR CHANNEL CH1 e Fault or Overrange on power up Certain toxic sensors indicate off scale low or high at power up and quickly drift towards zero This is normal behavior e Continuous Fault indication Remove sensor and examine for moisture or discoloration Replace sensor if wet or discolored Fault indication generally indicates sensor useful life is exhausted e Sensors left unpowered for more than 3 months are subject to accelerated degradation and may demonstrate a permanent loss of sensitivity SENSOR FAILS CALIBRATION e Sensor reading during zero calibration exceeds upper limit of zero sensor is defective and should be replaced Sensor reading during span calibration too low sensor may be defective However it may be possible to temporarily continue operation by increasing PREAMP GAIN GDS 68XP AND RECEIVING DEVICE DISPLAYED VALUES DON T MATCH e Check that zero and full scale range values match between GDS 68XP and receiving device controller Use DIAGNOSTICS menu to force the OUTPUT channel Ch2 to 12mA and verify half scale reading on remote controller e Check for high impedance shorts to ground on 4 20mA wiring Page 50 GDS 68XP Operation amp Maintenance Manual Revision 3 4 e f 4 20mA output is off scale low or high and cannot be adjusted using DIAGNOSTICS mode 10 Power Supply board may be defective and should be replaced CONTROLLER MODBUS DATA INCORRECT e Verify that MODB
25. CH Sample Purge Hold Total Cycle Time Number Setting 1 2 3 4 Time Time Approximate 0 000 1 On Demand Sequence 30 min 12 0011 1 5 5 min 5 7 2 010 1 1 5 min 10 min 15 min 3 011 1 1 5 min 20 min 30 min 43 100 1 1 5 50 1 hour 101 1 1 5 min 110 min 2 hours 110 1 1 5 min 230 min 4 hours 111 1 1 5 min 350 min 6 hours NOTE 1 DIP SWITCH 4 IS USED FOR FACTORY SETUP AND SHOULD ALWAYS BE LEFT ON NOTE 2 SEQUENCE 1 amp 2 ARE FOR TEST PURPOSES AND SHOULD NOT BE USED WITH ACTUAL SAMPLES NOTE 3 RECOMMENDED MINIMUM FOR MOST APPLICATIONS RECOMMENDED MINIMUM SEQUENCE FOR MERCAPTANS AND THT IS FOUR HOURS 1101 Page 65 GDS 68XP Operation amp Maintenance Manual Revision 3 4 GASMAX CX Version 1 01 If more than three MODBUS TCP devices are accessing the GASMAX CX at one time there is a possibility that the TCP stack will overflow and cause a reboot This is indicated by a 1 minute indication of 0 on the output channel Fixed in version 1 02 SEQUENCER Version 2 41 If the RUN button is pressed while the sequencer is in Demand wait mode no sequence will occur Fixed in version V2 42 If the RUN button is pressed while the sequencer is set to On Demand mode and the RUN button is pressed during purge hold mode no sequence will occur Fixed in version 2 42 Page 66
26. Cal Zero 0 0 Cal Span App Specific Set to match calibration gas Channel 2 Alarm 1 Setpoint 2096 of scale Latching No Trip On High On Delay 0 Off Delay 0 Deadband 196 Alarm 2 Setpoint 4096 of scale Latching No Trip On High Page 61 GDS 68XP Operation amp Maintenance Manual Revision 3 4 On Delay 0 Off Delay 0 Deadband 196 Alarm 3 Enabled No Setpoint 60 of scale Latching No Trip On High On Delay 0 Off Delay 0 Deadband 196 Fault Alarm Setpoint 10 of scale Data From Sensor Type Al 4 20mA Range 0 20mA Min Raw 800 Set at factory do not adjust Max Raw 4000 Set at factory do not adjust Filter Samples 5 Local Cal No Marker Enabled No Marker 96 15 63 Marker As IN CAL Sensor Life No Temp Comp 40 Gain Offset 1 00 0 00 30 Gain Offset 1 00 0 00 20 Gain Offset 1 00 0 00 10 Gain Offset 1 00 0 00 0 Gain Offset 1 00 0 00 10 Gain Offset 1 00 0 00 20 Gain Offset 1 00 0 00 30 Gain Offset 1 00 0 00 40 Gain Offset 1 00 0 00 Page 62 GDS 68XP Operation amp Maintenance Manual Revision 3 4 50 Gain Offset 1 00 0 00 Configure Tag Name GDS 68XP Eunits Mg m3 Zero 0 Span 50 Decimal
27. E 9 6 SYSTEM SETTINGS MENU 40 FIGURE 9 7 DIAGNOSTICS MENU TREE sn dites entrain eer eese cine 41 FIGURE 12 1 GDS 68XP SAMPLE DRAW COALESCING FILTER SPARE 52 FIGURE 12 2 GDS 68XP LOW PRESSURE COALESCING FILTER SPARE 53 FIGURE 12 3 GDS 68XP HIGH PRESSURE COALESCING FILTER SPARE PARTS 54 FIGURE 12 4 GDS 68XP HIGH PRESSURE BYPASS FILTER SPARE 55 Page 6 GDS 68XP Operation amp Maintenance Manual Revision 3 4 FIGURE 12 5 GDS 68XP SENSOR HEAD EXPLODED VIEW nennen nennen nnne FIGURE 13 1 GDS 68XP DIMENSIONS NEMA 4X FIGURE 14 1 GDS 68XP WIRING Page 7 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Important Read Before Installation Users should have a detailed understanding of GDS 68XP operating and maintenance instructions Use the GDS 68XP only as specified in this manual or detection of gases and the resulting protection provided may be impaired Read the following WARNINGS prior to use WARNINGS e GDS 68XP process monitor described in this manual must be installed operated and maintained in accordance wi
28. NTER CAL MODE ATTEMPTING TO CALIBRATE THE GASMAX WAIT UNTIL THE SEQUENCER IS IN PURGE HOLD MODE AS DURING A SAMPLE SEQUENCE WILL RESULT IN INDICATED BY L2 GREEN FLASH A CALIBRATION ERROR PRESS THE CAL KEY FOLLOWED BY THE EDIT KEY THE APPLY ZERO GAS SCREEN WILL APPEAR L2 WILL CHANGE TO SINGLE FLASH PURGE AIR PUMP WILL TURN ON AND AMBIENT ZERO AIR WILL FLOW INTO THE SENSOR FLOW CELL SET THE ZERO VALUE IF THERE IS A POSSIBILITY THAT TARGET GAS ALLOW THE READING TO STABILIZE AND PRESS THE EDIT KEY TO MAY BE PRESENT IN AMBIENT AIR USE A ACCEPT THE CURRENT READING AS ZERO CYLINDER OF ZERO AIR IN PLACE OF PURGE AIR IF ZERO READING IS WITHIN LIMITS THE ZERO CAL SUCCESS SCREEN WILL MOMENTARILY APPEAR THE APPLY SPAN GAS SCREEN WILL APPEAR SET THE SPAN VALUE ALLOW THE GAS TO FLOW FOR ABOUT AS CONNECT THE SPAN GAS AS SHOWN ABOVE SET THE RUN CAL LONG AS IT DOES DURING A NORMAL VALVE TO CAL AND TURN ON THE REGULATOR VERIFY FLOW ON SEQUENCE USUALLY BETWEEN THREE AND THE FLOW METER ALLOW THE READING TO STABILIZE AND PRESS FOUR MINUTES THE EDIT KEY TO ACCEPT THE CURRENT READING AS SPAN IF SPAN READING IS WITHIN LIMITS THE SPAN CAL SUCCESS SCREEN WILL MOMENTARILY APPEAR THE GASMAX DUAL SCREEN WILL REAPPEAR SHOWING CHANNEL 1 IN PURPLE CAL DELAY COMPLETE CALIBRATION ONCE CAL PURGE DELAY IS COMPLETE THE DISCONNECT THE SPAN GAS CYLINDER AND SET THE RUN CAL SEQUENCER WILL RETURN T
29. O THE VALVE BACK TO RUN PURGE HOLD MODE Figure 7 1 Calibration Procedure Cal Port Page 29 GDS 68XP Operation amp Maintenance Manual Revision 3 4 CALIBRATION PROCEDURE INLET PORT SAMPLE Calibration using the Inlet Port will more closely approximate the actual sample gas flow path through the filter regulator and sequencer valve Connect the calibration gas cylinder and regulator to the input port either directly or via a customer supplied three way valve such that the input can be connected to sample or calibration gas CALIBRATION PROCEDURE INLET PORT OBTAIN THE FOLLOWING ITEMS 1 CYLINDER OF CALIBRATION GAS WITH FIXED FLOW REGULATOR AND LENGTH OF FLEXIBLE TUBING 2 CYLINDER OF ZERO AIR IF NECESSARY IF NOT PREVIOUSLY DONE 1 VERIFY THAT THE CHANNEL 1 CAL SPAN VALUE MATCHES THE CAL 2 VERIFY THAT THE CALIBRATION GAS IS NOT EXPIRED IBRATION GAS TO BE USED ENTER CAL MODE WAIT UNTIL THE SEQUENCER IS IN PURGE HOLD MODE AS INDICATED BY L2 GREEN FLASH PRESS THE CAL KEY FOLLOWED BY THE EDIT KEY ATTEMPTING TO CALIBRATE THE GASMAX DURING A SAMPLE SEQUENCE WILL RESULT IN A CALIBRATION ERROR THE APPLY ZERO GAS SCREEN WILL APPEAR L2 WILL CHANGE TO SINGLE FLASH PURGE AIR PUMP WILL TURN ON AND AMBIENT ZERO AIR WILL FLOW INTO THE SENSOR FLOW CELL SET THE ZERO VALUE ALLOW THE READING
30. R SAMPLE 3 APPLY 24VDC POWER L1 L2 FLASH GASMAX DISPLAY ACTIVE PUMP ON PURGE AIR FLOWING GDS 68XP WARMUP SENSOR STABLE 15 MINUTES DURING WARMUP PERFORM STEPS 4 5 6 BELOW 4 ADJUST FLOW METER VALVE FOR 0 5 LPM ADJUST FOR LPM PURGE AIR FLOW 5 CHECK TIME OF DAY CLOCK FOR TIMEZONE CHANGES TO NETWORK SETTINGS ARE NOT SET HOST NAME AND MEASUREMENT NAME RECOGNIZED UNTIL NEXT POWER UP SET ETHERNET NETWORK PARAMETERS SEQUENCE RETURN TO STEP 3 IF CHANGED 6 OPTIONAL VERIFY 4 20MA SIGNAL TO REMOTE USE DIAGNOSTICS MENU TO FORCE CHANNEL 2 DCS OR PLC OUTPUT TO 4MA 20MA AND VERIFY READING ON RECEIVING DEVICE GDS 68XP COMPLETES FIRST SEQUENCE AND ENTERS PURGE HOLD MODE OUTPUT FLOW FAULT L2 GREEN FLASHING 7 OPEN SAMPLE INLET VALVE VERIFY PRESSURE ON PRESSURE GAUGE 8 PRESS BYPASS AND ADJUST REGULATOR FOR DO NOT RE ADJUST FLOW METER VALVE 0 5 LPM SAMPLE GAS FLOW RAW SENSOR OUTPUT SHOULD INCREASE IF TARGET GAS PRESENT 9 PRESS RUN TO EXIT BYPASS CLOSES SAMPLE VALVE AND RETURNS SEQUENCER TO PURGE HOLD MODE GDS 68XP COMPLETES PURGE HOLD GDS 68XP WILL RUN NEW SAMPLE SEQUENCES APPROXIMATELY EVERY FOUR HOURS ALLOW NEW UNIT TO RUN SEVERAL SEQUENCES BEFORE PROCEEDING 10 PERFORM SENSOR CALIBRATION SEE CHAPTER 7 GDS 68XP INSTALLATION COMPLETE Page 27 GDS 68XP Operation amp Maintenance Manual Revision 3 4 CALIBRATION OVERVIEW Calibration is critically important to ensure cor
31. Sensor Fails Calibration GDS 68XP and Receiving Device Displayed Values Don t Match Controller MODBUS Data Incorrect Controller Showing MODBUS COMM ERROR GDS 68XP Display Blank 12 SPARE PARTS 13 DRAWINGS AND DIMENSIONS 14 WIRING DIAGRAMS 15 GASMAX CX GDS 68XP FACTORY DEFAULT SETUP 16 SEQUENCER SETTINGS DIP SWITCH VERSIONS 17 KNOWN ERRATA Page 5 34 35 36 37 39 40 41 42 42 50 50 50 50 50 51 51 51 52 57 58 59 65 66 GDS 68XP Operation amp Maintenance Manual Revision 3 4 TABLE OF FIGURES FIGURE 3 1 TOXIC SENSOR 5 5 0 eene nnn nnn nnne AATA 11 FIG RE 3 2 SEQUENCE TIMING eaaet ee eter e eso e b RARE guten 11 FIGURE 3 3 RECOMMENDED MINIMUM SEQUENCE TIMES 11 FIGURE 4 1 GDS 68XP FLOW DIAGRAM 55 12 FIGURE 4 2 GDS 68XP SAMPLE enne nennen 13 FIGURE 4 3 GDS 68XP MAXIMUM TIMING 13 FIGURE 4 4 GDS 68XP FLOW DIAGRAM SAMPLE 14 FIGURE 5 1 GDS 68XP HIGH PRESSURE STANDARD FILTER 15 FIGURE 5 2 GDS 68XP POWER AND SIGNAL WIRING 000 16 FIGURE 5 3 RELAY MODBUS 6 17 FIGURE 5 4 MODBUS WIRING JUNCTION nennen n
32. TCP interface and optional RS 485 serial ports if installed Security Code to Lock Reds Security Settings Menu allows the user to restrict operation for some Modbus web Code 1234 GaSe Geo or all of the features as well as provide a programmed contact name System ps v1 00 System Settings Menu contains settings that are unit specific These Configure Digital Input View Event Log Clear Event Log View Sensor Life include unit name time and date warm up and calibration delay ES gt settings and Event Log Diagnostics p Relays Diagnostics Menu comprehensive set of tools that can be used to Analog Inputs Analog Outputs CED TESE Serial Ports ADC Readings activate relays simulate output values and test serial ports Figure 9 1 Main Menu Tree Page 35 GDS 68XP Operation amp Maintenance Manual Revision 3 4 ALARM OUTPUTS MENU The Alarm Outputs Menu controls the four optional alarm relays if installed These setting include relay programming acknowledge failsafe mode and specific input override options NOTE The Alarm Modbus board containing the 3x alarm relays and 1x fault relay is optional on the GDS 68XP Alarm Outputs Relay 1 Relay 2 Relay 3 All three relay outputs are identical and can be set to respond to channel 1 or channel 2 events The fault relay is always dedicated to Relay x Alarm 1 Alarm 2 Alarm 3 channels can activa
33. TED BY A SCREEN OR FILTER TO KEEP INSECTS FROM ENTERING THE EXHAUST PORT AND NESTING IN THE SENSOR FLOW CELL DANGER MAKE SURE EXHAUST GAS IS DIRECTED AWAY FROM PERSONNEL AND EQUIPMENT ESPECIALLY SUMPS OR LOW LYING AREAS WHERE HEAVY GASES SUCH AS HYDROGEN SULFIDE CAN BUILD UP OVER TIME HYDROGEN SULFIDE IS DEADLY AND EXPOSURE CAN RESULT IN INJURY OR DEATH Page 22 GDS 68XP Operation amp Maintenance Manual Revision 3 4 INSTALLATION SUMMARY DO S AND DON TS Select an installation location that protects the unit from shock vibration and damage Always mount the GDS 68XP vertically to ensure proper operation of the low flow switch e sure the power wiring is appropriate for the DC load and distance e DC signal wiring and AC heater wiring separate e sure sample conditioning is appropriate to the quality of the sample e Observe maximum inlet length recommendations e Always provide an independent sample exhaust line e sure that exhaust gas is directed away from personnel and vented to a safe area where exhaust gas can dissipate e f mounting the unit outdoors protect all exposed vents or intakes with screens or filters to keep insects moisture or dirt from entering the device Page 23 GDS 68XP Operation amp Maintenance Manual Revision 3 4 OVERVIEW The GDS 68XP consists of an electronic sequencer that controls and monitors the sample measurement purge opera
34. US A and B signals daisy chain power 0 Sn8aowW wiring requires that two wires be installed in the 24 and GND terminals on the GDS 68XP I O Power Supply board This can be difficult if wire sizes are larger than 18GA For these reasons if MODBUS is required GDS Corp recommends the addition of the MODBUS Wiring Junction Box see Fig 5 7 This option minimizes the need to access wiring inside the GDS 68XP provides individual wire landing points for incoming and outgoing MODBUS and power wiring and shields and makes it easy to temporarily disconnect the GDS 68XP Figure 5 4 MODBUS Wiring Junction Box power or MODBUS connections without affecting any other MODBUS device Page 18 GDS 68XP Operation amp Maintenance Manual Revision 3 4 AC HEATER OPTIONAL The 200 watt AC powered heater is recommended for outdoor applications where ambient temperatures may fall below freezing for extended periods of time The heater is available in either 110VAC or 230VAC models Access to the heater wiring is via a separate NPT fitting on the bottom of the heater junction box Note that all high voltage AC wiring must be kept separate from lower voltage DC and signal lines Fixed Thermostat ON below 50 F 10 C Heater Element Access to heater wiring via NPT fitting on bottom of junction box enclosure cutout not provided Ther
35. US master is requesting data from correct data register 31002 e Verify that controller MIN and MAX count settings are correct MIN counts should be 800 which corresponds to 4mA and MAX counts should be 4000 which corresponds to 20 mA e Verify that the GDS 68XP MODBUS address matches the address programmed into the controller s channel configuration CONTROLLER SHOWING MODBUS COMM ERROR Check for incorrect MODBUS polarity swap and B if unsure no damage will occur e Verify that MODBUS master is requesting data from correct MODBUS address e Verify that MODBUS master is requesting data from register 31002 e Verify that there are no other MODBUS slave devices with identical MODBUS address GDS 68XP DISPLAY BLANK e Verify DC power at IO Power Supply board TB2 terminals 1 24 and 4 Gnd e Verify ribbon cable connected between 10 Power Supply board and Display Assembly Page 51 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Sequencer Assembly Sequencer Actuators 20 0142 Sequencer processor PCB sample draw 1200 0234 Sample Pump 20 0143 Sequencer actuators PCB sample draw includes 1200 0047 Flow Switch pump flow switch and 3 way valve sample draw 1200 0034 3 valve 1200 0034 Flame Arrestors 3 Display 10 0387 1 0 Board 10 0390 Optional Relays amp MB 10 0388 Sensor Head 10 0247 Flow Cell 10 0205 Filter 1200 0056
36. a value of less than 1096 of full scale during the recovery interval the sensor may be saturated with sample gas and the GDS 68XP will indicate a recovery fault PEAK ALGORITHM FAULT During the sample sequence the GDS 68XP looks for a level peak value If no level peak is found the GDS 68XP will indicate an algorithm fault SAMPLE OR PURGE AIR FLOW FAULT If the sequencer senses a lack of flow for more than 10 seconds during the sample sequence the GDS 68XP will indicate a flow fault CALIBRATION FAULT If the sensor output higher than 1096 of scale or lower than 1096 of scale when a sequence starts the GDS 68XP will indicate a calibration fault The GDS 68XP will also indicate a calibration fault if the GASMAX is placed in Cal Mode at any time during a sample sequence SENSOR FAIL FAULT If the sensor is removed or fails in such a way as to cause a channel 1 sensor FAULT reading during a sample or sequence the GDS 68XP will indicate a sensor fault FAULT REASON OF OUTPUT RANGE RANGE SCALE MA 0 3 00 0 100 OVER RANGE INPUT EXCEEDS MAX RANGE VALUE 105 21 3 15 105 RECOVERY FAULT SENSOR FAILS TO DROP BELOW 10 1596 1 6 MA 0 45 15 PEAK FIND FAULT PEAK FIND ALGORITHM TIMES OUT 17 596 1 2 MA 0 52 17 5 FLOW FAULT GAS OR PURGE AIR FLOW DISRUPTED 2096 0 8 MA 0 60 20 FOR gt 10 SECONDS CALIBRATION GASMAX CAL DURING SEQUENCE OR 22 596 0 4 MA 0
37. and all appropriate electrical codes Generally these codes require rigid metal conduit poured seals and other installation elements necessary to ensure safety For maximum protection against RF interference or electrical surge the GDS 68XP enclosure and interconnecting conduit must be properly grounded INTRINSICALLY SAFE INSTALLATION The GDS 68XP is not designed or certified for use as an Intrinsically Safe device Page 9 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Model Power Input Display Sensor Types Inlet Pressure Requirements Draw Distance Accuracy Standard Output Temperature operating Temperature inert Memory Materials Dimensions Approvals Warranty GDS 68XP Process Monitor for Low Oxygen Applications 24VDC x 5 at lt 12 watts High resolution color LCD with engineering units bargraph and 30 minute trend Electrochemical sensors for toxic gases Sample draw Ambient to 5 inches of water column Low pressure no regulator 5 inches water column to 25 psig 10 max High pressure standard filter 10 psig to 1500 psig High pressure combination filter 10 psig to 1500 psig Demonstrated up to 100 feet of OD tubing 5 of full scale typical Three wire 4 20mA current source outputs with fault and overrange indication Maximum loop resistance is 750 ohms with standard 24VDC supply Ethernet RJ 45 with built in MODBUS TCP interface and web
38. be due to temperature extremes high levels of target gas the presence of certain gases that poison toxic sensors and other environmental factors Always check the flow meter for the presence of moisture In the event that moisture or liquid is drawn in the GDS 68XP the entire unit should be disassembled and cleaned In some cases the flow meter or flow switch may need to be replaced If liquid is drawn into the GDS 68XP always inspect the sensor for signs of damage Page 32 GDS 68XP Operation amp Maintenance Manual Revision 3 4 FAULT AND OVERRANGE CONDITIONS The GDS 68XP contains multiple microprocessors that monitor flow rates and sensor readings to detect problems In the event that a fault occurs during a sample sequence the 4 20mA output will indicate one the following fault condition POWER UP Immediately after power up the GDS 68XP outputs OmA FAULT for 8 seconds and then 4mA 0 until the first reading is successfully recorded This allows a remote device to determine if the GDS 68XP was forced to restart as a result of a power failure INPUT OVERRANGE FAULT To protect the electrochemical sensor in the event of an over range condition during a sample measurement sequence the sample valve will automatically and the purge air pump will be activated to force fresh air into the sensor cell SENSOR RECOVERY FAULT After the sensor output is monitored for a prompt return to zero If the output does not return to
39. bes or local analyzers If the gas level is known the following procedure can be used to adjust the output of the GDS 68XP to match the current level of target gas CALIBRATION PROCEDURE STREAM SAMPLE OBTAIN THE FOLLOWING ITEMS 1 CURRENT VALUE OF TARGET GAS PRESENT IN THE STREAM MEASURED INDEPENDENTLY 2 CYLINDER OF ZERO AIR IF NECESSARY SET CAL SPAN VALUE SET THE CHANNEL 1 CAL SPAN VALUE TO MATCH THE PREDETERMINED LEVEL OF TARGET GAS IN THE GAS STREAM THIS PROCEDURE IS ONLY RECOMMENDED IF CERTIFIED CALIBRATION GAS IS UNAVAILABLE ENTER CAL MODE WAIT UNTIL THE SEQUENCER IS IN PURGE HOLD MODE AS INDICATED BY L2 GREEN FLASH PRESS THE CAL KEY FOLLOWED BY THE EDIT KEY ATTEMPTING TO CALIBRATE THE GASMAX DURING A SAMPLE SEQUENCE WILL RESULT IN A CALIBRATION ERROR THE APPLY ZERO GAS SCREEN WILL APPEAR L2 WILL CHANGE TO SINGLE FLASH PURGE AIR PUMP WILL TURN ON AND AMBIENT ZERO AIR WILL FLOW INTO THE SENSOR FLOW CELL SET THE ZERO VALUE ALLOW THE READING TO STABILIZE AND PRESS THE EDIT KEY TO ACCEPT THE CURRENT READING AS ZERO IF THERE IS A POSSIBILITY THAT TARGET GAS MAY BE PRESENT IN AMBIENT AIR USE A CYLINDER OF ZERO AIR IN PLACE OF PURGE AIR IF ZERO READING IS WITHIN LIMITS THE ZERO CAL SUCCESS SCREEN WILL MOMENTARILY APPEAR THE APPLY SPAN GAS SCREEN WILL APPEAR SET THE SPAN VALUE PRESS BYPASS ON THE SEQUENCER AND VERIFY FLOW ON THE
40. d and pushing straight up Step 8 Reassemble the sensor head cover and flow cell and reattach the sample inlet and outlet tubing Step 9 Apply power allow the sensor to warm up for several hours Step 10 Perform a complete calibration GDS 68XP Operation amp Maintenance Manual Revision 3 4 The GASMAX CX gas monitor used in the GDS 68XP has a menu driven user interface that allows the operator to review and adjust a wide range of settings In the GDS 68XP channel 1 of the GASMAX CX measures the raw sensor gas level and channel 2 provides continuous display output and alarming on the stored value retained in the sequencer memory To access the Main Menu activate the EDIT key with a magnetic wand Main Menu Alarm Outputs Channel Settings Comm Settings Security System Diagnostics alarm Outputs Alarm Output Menu contains settings that control the four optional elay 1 a Kel alarm relays if installed These setting include relay programming and off delay failsafe mode and specific input override Channel Settings x T Channel 1 gt Channel Settings Menu contains settings specific to each channel Channel 2 gt These include tag names range calibration settings and alarm levels Comm Settings Comm 1 settings Comm Settings Menu contains settings specific to the Ethernet COMM 2 Settings ModbusTCP Network Settings Troubleshooting network interface MODBUS
41. ed at least once every three months Furthermore during the initial six months of operation the GDS 68XP should be checked more often to verify that the sensor is operating properly and that some component of the sample gas mixture has not damaged the sensor or change the sensor s response to the target gas compound IMPORTANT FOR MAXIMUM ACCURACY USE CALIBRATION GAS WITH A CONCENTRATION VALUE THAT IS GREATER THAN 25 OF FULL SCALE AND LESS THAN 75 OF FULL SCALE Before beginning calibration make sure you have the following items A cylinder of calibration gas fixed flow regulator and a length of flexible tubing Page 28 GDS 68XP Operation amp Maintenance Manual Revision 3 4 CALIBRATION PROCEDURE CAL PORT SAMPLE Calibration using the built in calibration port is the fastest and most convenient method When the GASMAX enters CAL MODE the purge air pump automatically turns on to provide zero air flow from ambient air sample air flow is provided by the fixed flow regulator connected to the calibration gas cylinder CALIBRATION PROCEDURE CALIBRATION PORT OBTAIN THE FOLLOWING ITEMS 1 CYLINDER OF CALIBRATION GAS WITH FIXED FLOW REGULATOR AND LENGTH OF FLEXIBLE TUBING 2 CYLINDER OF ZERO AIR IF NECESSARY IF NOT PREVIOUSLY DONE 1 VERIFY THAT THE CHANNEL 1 CAL SPAN VALUE MATCHES THE CALIBRATION GAS TO BE USED 2 VERIFY THAT THE CALIBRATION GAS IS NOT EXPIRED E
42. ed purge air filter is in place and that a cover is placed over the Cal Gas Inlet port Always mount the GDS 68XP in a vertical position to ensure proper operation of flow switch and filter drains The non metallic enclosure option is strongly recommended if unit is to be installed outside or in areas where high or low temperature extremes may occur NOTE TEMPERATURES BELOW 0 MAY KEEP THE PURGE AIR PUMP FROM STARTING Always use recommended conduit and poured seals for signal and power wiring installation in hazardous areas Consult local codes and regulations where appropriate Power amp Signal Input Purge Air Inlet Sensor Sensor Flow Cell e Sample Flow Meter Inlet Filter Drain ACHeater Sample Exhaust Figure 5 1 GDS 68XP High Pressure Standard Filter Page 15 GDS 68XP Operation amp Maintenance Manual Revision 3 4 POWER amp SIGNAL CONNECTIONS Recommended DC Wire Gauge 100 ft 818 GA To access the power and signal wiring remove the cover from the explosion proof enclosure Connect a source of 24VDC 10 power 100 to 500 ft 16 GA to wiring terminals J1 1 24V and J1 3 GND The 4 20mA source 500 to 1000ft 14 GA output is available at J1 2 See Fig 5 2 ON DEMAND SEQUENCE INPUT If the on demand sequencer mode is selected the GDS
43. ess 169 254 100 10 Netmask 254 254 0 0 Troub leshooti ng View Error Count Clear Error Count Comm X Menu both comm port setting menus are identical Type Modbus Slave determines whether the MODBUS port is a master or slave Baud Rate Sets the baud rate for the serial port Options are 9600 19200 38400 57600 and 115200 baud Slave ID Sets the MODBUS slave ID for the serial port Byte Order sets the byte order for words larger than 16 bits Enable LEDs If YES front panel LEDs indicate MODBUS transmission MODBUS TCP Menu Slave Settings Byte Order sets the byte order for words larger than 16 bits Master Settings Timeout Length of time in mSec that master will wait for a reply before indicating a comm timeout Poll Delay Length of time in mSec between sequential read requests Enable LEDs if YES front panel LEDs indicate MODBUS TCP transmission Network Settings Menu DHCP Enabled If YES uses a remote DHCP server to establish a network address If NO uses fixed address Hostname Character string that defines device network name IP Address Network address If DHCP enabled will show address assigned by DHCP server If DHCP disabled is IP address programmed by user Net mask Network mask value See above Gateway Network gateway value See above Troubleshooting Menu View Error Count View a menu that tracks the number of network errors Clear Error Count
44. ing a calibration sequencer Enables remote devices to track In Cal status Alarm Refresh See GASMAX CX manual Digital Input Menu Mode Determines action if digital input fault ack input is activated Normally If Normally OPEN the action will occur if the contacts close if normally CLOSED the event will occur if the contacts open Channel Determines which channel output is affected Event Log Event Log Format The event log includes the date time and list of events that occur Events include cold boot system boot alarm reset remote alarm reset log cleared config edit A1 A2 and A3 in and out fault in and out calibration in and out calibration fail communications error config error and marker event Clear Event Log Clears all entries in the event log View Sensor Life Menu Life Computed value based on initial stored gain value when sensor was first calibrated If new gain equals original gain sensor life 10096 If new gain equals twice original gain sensor life 0 Figure 9 6 System Settings Menu Tree Page 40 GDS 68XP Operation amp Maintenance Manual Revision 3 4 DIAGNOSTICS MENU The Diagnostics page provides tools for use during setup or testing Tests for optional features are not available if the feature is not installed Diagnostics Relays Analog Inputs Analog Outputs LED Test Serial Ports ADC Readings warning Diagnostic mode A
45. larms will not Be processed FUNCTION AND REQUIRES A DEVICE REBOOT ON EXIT WARNING ENTERING DIAGNOSTICS MODE DISABLED ALARM Edit OK Next Cancel Relays Relays Menu Relay 1 off Relay 2 off Allows individual relays to be turned on or off under user control Only Relay 3 off Fault Relay on available if optional Relay Modbus board is installed Ch 1 EC Loc Counts 856 Temp 24 5 degc Analog Inputs Menu Shows current input readings for channel 1 and channel 2 Counts 0 Current 0 00 Analog Outputs Analog Outputs Menu 4 20mA out1 Shows the live output values analog channel 1 and analog channel 2 4 20mA Out2 OmA Also shows the feedback monitor reading for both channels out1 Fdbk 0 07 Out2 Fdbk 0 06 LED Test Menu LED Test Cycles the external LED Comm Test Comm Test Menu Connect Loopback Performs a loopback test to verify proper operation of the serial Port 1 gt 2 Bad components Only available if optional Relay Modbus board is installed Port 2 gt 1 Bad 420 out1 Fdbk 1 ADC Readings 420 Out2 Fdbk 2 Displays values monitored by internal analog to digital converters Sensor V SensrAmp PSU Figure 9 7 Diagnostics Menu Tree Page 41 GDS 68XP Operation amp Maintenance Manual Revision 3 4 The GDS 68XP features a full complement of user accessible MODBUS registers that can provide a complete snapshot of the gas detector configuration This incl
46. me Approximate 0 On Demand Sequence 1 hour 1 12 15 min 40 min 1 hour 2 12 15 min 105 min 2 hours 3 12 15 min 165 min 3 hours 4 12 15 min 225 min 4 hours 5 12 15 min 285 min 5 hours 6 12 15 min 345 min 6 hours 7 12 15 min 465 min 8 hours Figure 6 2 Sequence Timing BYPASS disables the sequencer and allows sample gas to flow directly into the sensor for testing purposes To enter BYPASS mode press and hold the BYPASS button To exit Bypass press and hold the RUN button Bypass mode will automatically exit after 15 minutes of operation Bypass is only available during Purge Hold sequence RUN Pressing RUN for five seconds during the Purge Hold sequence will initiate a new cycle L1 AND L2 indicate the status of the sequencer processor MODE L1 RED L2 GRN PUMP VALVE DESCRIPTION START UP SIMULTANEOUS FLASH OFF OFF FIRST 8 SECONDS ONLY WARM UP ALTERNATE FLASH ON OFF INITIAL WARM UP ONLY ON DEMAND SLOW FLASH OFF OFF WAITING FOR REMOTE START ACTIVE SAMPLE SEQUENCE CONDITION 1 FLASH OFF OFF ON ON GAS APPLIED TO SENSOR FOR 10 SEC DELAY 1 FLASH OFF ON OFF PURGE AIR FOR FIVE MINUTES CHARGE 2 FLASHES OFF OFF ON ON GAS APPLIED TO SENSOR READING 3 FLASHES OFF OFF ON ON IDENTIFY PEAK STORE READING RECOVERY 4 FLASHES OFF ON OFF PURGE AIR TO lt 10 OF FULL SCALE Purge Hold Mode PURGE HOLD OFF 2 FLASHES ON OFF SENSOR AIR PURGE BYPASS MODE ALTERNATE FLASH
47. momentarily causes the GDS 68XP display to sequence display screens between DUAL DISPLAY RAW SENSOR TREND PPM OUTPUT TREND RAW SENSOR and PPM OUTPUT Figure 6 4 GDS 68XP GASMAX Display Sequence RAW SENSOR displays the calibrated gas value being read by the sensor at any moment As such it will increase when the 3 way valve opens to allow sample gas into the unit and will then drop back to zero during purge and purge hold Use the Raw Sensor Trend screen to monitor the sensor s response to sample gas PPM OUTPUT displays and holds the maximum value found during the most recent sample sequence Its value is updated each time the sequencer identifies a new maximum ppm value DUAL DISPLAY shows both RAW SENSOR and PPM OUPTUT values on a single screen Page 26 GDS 68XP Operation amp Maintenance Manual Revision 3 4 GDS 68XP STARTUP PROCEDURE Before start up review Chapter 4 Operation for information on operating modes and indications as well as Chapter 6 Sequencer Controls and Indicators Figure 6 3 provides a handy reference to the red and green LEDs L1 and L2 that indicate the current status of the sequencer processor ITEM NOTES 1 MAKE SURE SAMPLE OUTLET IS CONNECTED SAMPLE GAS CAN BE DEADLY ALWAYS MAKE CLOSE INLET AND FILTER DRAIN VALVES SURE SAMPLE OUTLET IS DIRECTED TO A SAFE AREA 2 SET SEQUENCE SWITCH TO 4 SET FOR 4 HOU
48. mostat ACHOT NEUTRAL Red White AC GND iii Heater Element Figure 5 5 200W AC Heater Wiring Local codes and good wiring practice require an AC shutoff switch within sight of the heater assembly for maintenance and testing IMPORTANT Keep all electrical fittings tight while circuits are alive PURGE AIR INLET Purge air should be drawn from a source of ambient air that is clean and free of significant levels of hydrogen sulfide or similar toxic gas GDS Corp recommends placing the Purge Air inlet some distance from the GDS 68XP in a location that is free from background gas and protected from heavy rains water spray and snow or ice Included with the unit is a 4 screen fitting that must be placed over the open end of the purge air inlet to keep dust dirt water droplets and insects from entering the tubing and being drawn into the purge air pump Page 19 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SAMPLE INLET The length of time it takes gas to flow from the sample source to the GDS 68XP inlet should not exceed 30 seconds to ensure that fresh sample is available at the beginning of each measurement cycle For 4 OD stainless steel tubing and sample flow rates of approximately 0 5 liters per minute the maximum length should be no more than 60 feet 20 m Smaller diameter tubing will allow longer runs but may be subject to clogging if the sample contains particulate or moisture
49. nections Optional MODBUS Connections Optional AC Heater Optional Purge Air Inlet Sample Inlet Filter Drain amp Filter Bypass Sample Exhaust Installation Summary Do s and Don ts Page 3 10 12 12 14 14 15 15 16 16 16 17 17 19 19 20 21 22 23 GDS 68XP Operation amp Maintenance Manual Revision 3 4 6 INITIAL SETUP 24 Overview 24 Sequencer Controls and Indicators 24 SEQUENCE 24 Bypass 25 Run 25 L1 and L2 25 GASMAX Controls and Display 26 RAW SENSOR 26 PPM OUTPUT 26 DUAL DISPLAY 26 GDS 68XP STARTUP PROCEDURE 27 7 CALIBRATION 28 Calibration Overview 28 Calibration Procedure CAL PORT SAMPLE 29 Calibration Procedure INLET PORT SAMPLE 30 Calibration Procedure STREAM SAMPLE 31 8 OPERATION and MAINTENANCE 32 Normal Operation 32 Cold Weather Operation 32 Normal Maintenance 32 Fault and overrange Conditions 33 Power Up 33 Input Overrange FAULT 33 Sensor Recovery FAULT 33 Peak Algorithm fault 33 Sample or Purge Air Flow fault 33 Calibration fault 33 Sensor Fail fault 33 Page 4 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Sensor Replacement 9 USER MENUS Alarm OUTPUTS Menu Channel Settings Menu Comm Settings Menu System Settings Menu Diagnostics Menu 10 MODBUS REGISTERS List of GDS 68XP MODBUS variables 11 TROUBLESHOOTING GUIDELINES Fault Indication on OUTPUT Channel CH2 Fault Indication on raw Sensor Channel CH1
50. ntenance Manual Revision 3 4 Page 47 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Page 48 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Ch 2 Balance 43295 3 N A Binary Ch 2 Heater Enable 43296 3 N A False NO True YES Ch 2 Heater Setpoint 43297 3 N A Modbus 32 bit IEEE 754 Floating Pt Page 49 GDS 68XP Operation amp Maintenance Manual Revision 3 4 FAULT INDICATION ON OUTPUT CHANNEL CH2 e Value shows 105 of scale indicates an OVERRANGE condition where the sample gas caused the sensor to read more than 100 of scale e Value shows 15 of scale indicates a NON RETURN TO ZERO FAULT during recovery mode Indicates sensor may be saturated with target gas Increase the purge interval to allow more time for the sensor to recover e Value shows 17 5 of scale indicates a SAMPLE PEAK IDENTIFICATION ALGORITHM FAULT peak was not found in maximum allotted time Check sample flow rates and sensor life e Values shows 20 of scale indicates a LOSS OF FLOW for more than 10 seconds during sample pre charge or sample recovery Check sample flow or pump performance e Value shows 22 5 of scale indicates a CALIBRATION fault either the resting input value at the start of the last cycle was higher than 1096 of scale OR a GASMAX calibration occurred during the cycle e Value shows 25 of scale indicates SENSOR FAULT from GASMAX monitor FAULT INDIC
51. odbus RTU serial ports Remote Alarm Acknowledge Modbus Wiring Modbus A Modbus B Relay Wiring Fault 1 NC Fault 1 Common Fault 1 NO Relay 3 NC Relay 3 Common Relay 3 NO Relay 2 NC Relay 2 Common Relay 2 NO 10 Relay 1 NC 11 Relay 1 Common 12 Relay 1 NO Shield Tie Point Modbus A Modbus B 1 2 3 4 5 6 7 8 9 MODBUS interface 4 0000000000009 Figure 5 3 RELAY MODBUS Connections Relays K1 K2 and K3 provide a contact closure if the Alarm 1 K1 or Alarm 2 K2 or Alarm 3 K3 limits are exceeded Alarms can be programmed to trigger above or below a certain value work as normal or failsafe and can be made to latch if desired Relay indicates a FAULT condition in the sensor microprocessor or flow system Remote Alarm Reset can be used to acknowledge an Alarm 2 relay contact closure Wiring from any remote pushbutton to TB3 should be shielded and protected from noise spikes to prevent false Alarm Reset commands WARNING RELAY CONTACTS ARE RATED FOR RESISTIVE LOADS ONLY INDUCTIVE LOADS MAY CAUSE ARCING WHICH SHORTENS LIFE AND MAY INTERFERE WITH SENSOR DATA MODBUS CONNECTIONS OPTIONAL The dual optional GDS 68XP MODBUS RTU interface allows remote controllers or PLCs to monitor most aspects of operation including real time data range and alarm setpoints and alarm and fault status bits The GDS 68XP interface suppo
52. or with ambient air to maintain the sensor in a sensitive oxygenated state Purge Air RAWSENSOR PPM OUTPUT Purge Air Pump VE Ch 1 Ch2 Inlet Switch Sensor Flow Cell Sample Inlet P Sample Outlet Run Cal Pressure Valve Filter Cal Gas Inlet Figure 4 1 GDS 68XP Flow Diagram Pressure At the beginning of each sequence the GDS 68XP performs Conditions the Sensor by allowing a small sample of gas to enter the sensor flow cell followed by a fixed 5 minute delay The 68XP then enters Sample Charge during which sample gas flows into the sensor flow cell for two minutes or until sensor output exceeds 25 of scale Once sample pre charge is complete the sequencer enters Read mode where the sequencer processor attempts to identify a stable peak value Once the sample value is Page 12 GDS 68XP Operation amp Maintenance Manual Revision 3 4 identified and stored the GDS 68XP enters Recovery mode where purge air flows into the sample flow cell Once the sensor output drops below 10 of scale the GDS 68XP transfers the stored reading to the 4 20mA and MODBUS output In the event that an overrange loss of flow peak find algorithm fault non return to zero fault sensor fault or calibration fault occurred during the sequence a specific fault indication value will be output in place of the measured value Finally the GDS 68XP enters Purge Hold
53. rect operation of the GDS 68XP The GASMAX CX built in CAL MODE function is designed to make calibration quick easy and error free a successful ZERO and SPAN calibration requires only four keystrokes It is important to note that a GASMAX calibration should only be performed during Purge Hold mode During each sample sequence the GDS 68XP sequencer checks for a number of different error conditions including overrange sensor fault sample peak identification fault and sensor non return to zero Since the sequencer expects a valid output from the GASMAX at all times if the GASMAX CX is placed in CAL MODE at any time during the sample sequence a CAL ERROR is generated Always check to be sure that the L2 GREEN indicator LED is flashing before performing a GASMAX calibration procedure Calibration can be performed in one of three ways If certified calibration gas is available the Cal Port Sample calibration technique is the fastest and most convenient method If a three way valve is installed in the sample stream inlet the Inlet Port Sample calibration technique is preferred as the calibration gas passes through the filter regulator control valve flow switch and flame arrestors more closely simulating the path taken by the actual sample gas Finally if calibration gas is not available but the stream contains a known amount of target gas the Stream Sample calibration technique is available In all cases the GDS 68XP should be calibrat
54. rts 9600 Baud RS 485 differential signaling only Access to each MODBUS RS 485 interface is via TB2 on the optional Relay MODBUS board mounted on the back of the GASMAX CX display module See Fig 5 3 Separate input and output terminals for MODBUS A and B signals are available A center terminal to tie incoming and outgoing shield connections is also provided Page 17 GDS 68XP Operation amp Maintenance Manual Revision 3 4 MODBUS system architecture requires that the devices in any MODBUS loop be connected in a daisy chain layout This minimizes signal reflections and improves signal noise margin A MODBUS Termination Jumper installs a load resistor across the MODBUS signal lines and should only be set to A ON at the last device in the string See Fig 5 3 Cable selection for MODBUS systems is important for both signal integrity and power distribution MODBUS RS 485 transmissions use low voltage differential signaling to achieve reasonable data rates over very long distances up to 4000 feet without a repeater 24 For MODBUS data signals GDS Corp recommends 20GA to GND 24GA twisted shielded cable Daisy chain power distribution A i p may require larger gauge wire since it is critical that the supply voltage for the GDS 68XP at the far end of the string not fall below 22VDC during power up Note that while the GDS 68XP has two sets of wiring terminals for MODB
55. server Optional Relay MODBUS interface with 3x 5A SPDT programmable alarm relays 0 to 50 C standard no enclosure Note Ambient temperature below 0 C may keep purge air pump from starting 20 C to 50 C with NEMA 4X enclosure and optional 200W AC heater Heater thermostat is set to 50 F and is not user adjustable 20 C to 55 C In cold weather GDS Corp recommends turning on the AC heater if installed for several hours before applying DC power On board non volatile memory retains all user settings Instrument housings Aluminum Tubing amp fittings 316 stainless steel Painted steel plate 21 x 21 x 8 NEMA 4x non metallic enclosure 24 x 24 x 8 GASMAX CX Gas Monitor CSA Certified Class Div 1 amp 2 Groups B C D Sequencer enclosure CSA certified for use in Class Div 1 areas Flame arrestors UL certified for use in Class 1 Div 1 areas Two years on electronics Page 10 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Type Target Gas Min Span Max Span Temp Range Warm Up 15 Hydrogen Sulfide 0 10 ppm 0 5000 ppm 0 C to 50 C 2 to 4hours 30 Mercaptan 0 15 ppm 0 30 ppm 0 C to 40 C 4 to 8 hours 31 THT 0 15 ppm 0 30 ppm 0 C to 40 C 12 to 24 hours 40 Odorants 0 15 ppm 0 50 ppm 0 C to 50 C 2 to 4hours 41 Spotleak 0 15 ppm 0 50 ppm 0 C to 50 C 2 to
56. te the relay Options are Off Ch1 Ch2 Ch1 and Fault Acknowledge Fail safe Acknowledge Determines if the alarm can be reset by an Acknowledge Override Alarm 1 2 and Fault Determines which channel or combination of Ch2 and Ch1 or Ch2 command YES or not NO Failsafe Determines if the relay is OFF when inactive NO or ON when inactive YES Failsafe connections thru the Normally Open connection will open automatically if the alarm activates or if power is lost Override Allows the relay to be dedicated to a specific channel alarm level or function such as calibration Settings that involve calibration allow the relay to be connected to a cylinder of calibration gas via a solenoid valve to enable automatic application of calibration gas if the unit is placed in Cal Mode Ch1 2 cal zero Chi cal Span Ch2 Cal Span 1 2 Cal Zero Span Figure 9 2 Alarm Outputs Menu Tree Page 36 GDS 68XP Operation amp Maintenance Manual Revision 3 4 CHANNEL SETTINGS MENU The Channel Settings Menu allows the user to adjust individual channel or sensor specific features Data in the Channel Settings Menu is uploaded from Smart Sensors and written back to any local Smart Sensor if changed in the menu Channel Settings Channel 1 E Channel 2 gt 2 events The fault relay is always dedicated to fault events Both channel setup menus are identical so only one is shown Channel x Alarm 1
57. th information contained herein Installation in any hazardous area must comply with all applicable restrictions requirements and guidelines for said hazardous areas It is the end user customer s final decision to ensure that the GDS 68XP is suitable for the intended use e The GDS 68XP is designed and constructed to measure the level of certain gases in backgrounds that contain low amounts of free oxygen Accuracy in atmospheres containing steam or inert gases cannot be guaranteed e Do not paint enclosure transmitter or sensor assembly Do not operate the GDS 68XP if its enclosure is damaged or cracked or has missing components Make sure the cover internal PCB s and field wiring are securely in place before applying power e Do not expose the GDS 68XP to electrical shock or continuous severe mechanical shock Protect the GDS 68XP from dripping liquids and high power sprays e Calibrate with known target gas at start up and check on a regular schedule at least every 90 days More frequent inspections are encouraged to spot problems such as dirt oil paint grease or other foreign materials in the sample tubing or in the sensor head e Periodically test for correct operation of the system s alarm events by exposing the sample extraction point to a calibration gas concentration above the High Alarm set point e Use only for applications described within this manual Page 8 GDS 68XP Operation amp Maintenance
58. tion and a dual channel GASMAX CX monitor that measures the raw sensor data Channel 1 and stores and displays the captured measurement Channel 2 SEQUENCER CONTROLS AND INDICATORS To access the GDS 68XP sequencer unscrew and remove the cover of the gray explosion proof enclosure The length of time between samples is determined by the SEQUENCE switch setting Sequencer control for testing and setup is managed by two pushbuttons BYPASS and RUN located on the sequencer board and the state of system sampling purging waiting can be determined by viewing status LEDs 411 and L2 PUMP and VALVE also located on the sequencer board SEQUENCE SWITCH 5 8 T BYPASS RUN E 5 11 12 EN PUMP Figure 6 1 GDS 68XP User Interface The GDS 68XP sequencer monitors the output of the GASMAX raw sensor channel and flow switch and controls the operation of the purge air pump and 3 way valve SEQUENCE switch setting determine the length of time between each sample cycle There are seven preset sample times and one on demand setting that allows an external PLC or DCS to command the start of a sample cycle Switch positions are numbered 0 to 7 clockwise starting from the bottom Page 24 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SEQUENCE Sequence Purge Hold Total Cycle Time Switch Time Ti
59. udes all real time data preset zero span and calibration values and user programmable text LIST OF GDS 68XP MODBUS VARIABLES Variable Name Alias Read Write Notes Ch 1 Analog Output Raw 31001 4 N A 12 bit value 800 4mA 4000 20mA Ch 2 Analog Output Raw 31002 4 N A 12 bit value 800 4mA 4000 20mA Ch 1 A2D Raw Counts 31003 4 N A 12 bit value from A D converter Ch 2 A2D Raw Counts 31004 4 N A 12 bit value from A D converter Page 42 GDS 68XP Operation amp Maintenance Manual Revision 3 4 SR 2 State 32021 4 N A True if relay 82 active SR 3 State 32022 4 N A True if relay active FR State 32023 4 N A True if fault relay active Page 43 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Ch 21 0 Error 33056 4 N A True if input output error Ch 2 Cal Flag 33057 4 N A True if calibration in progress Ch 2 Marker Flag 33058 4 N A True if marker active Ch 2 Linearize 33059 4 N A True if linearization table active Ch 2 Err Flashing 33060 4 N A True if channel error Page 44 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Gateway IP 40074 3 N A Ethernet port XXX XXX XXX XXX Page 45 GDS 68XP Operation amp Maintenance Manual Revision 3 4 Ch 1 Preamp gain 40433 3 N A Contact factory Ch 2 Preamp gain 40434 3 N A Contact factory Page 46 GDS 68XP Operation amp Mai
60. value Max value is 9999 Decimal Points Determines the number of displayed digits to the right of the decimal point Channel On Channel ON or OFF setting An OFF channel will have no effect on any alarm or output value Deadband 96 The value around zero for which the screen will show 0 0 Eliminates display of small values around zero due to sensor drift Calibrate Menu Offset Shows the computed offset value based on the latest calibration Gain Shows the computed gain value based on the latest calibration Cal Zero The value for the zero point calibration Cal Span The value for span calibration typically 50 of full scale Set Unity Gain Clears gain and offset to 1 00 and 0 00 respectively WARNING Set Unity Gain resets calibration data Figure 9 4 Channel Settings Menu Tree 2 Page 38 GDS 68XP Operation amp Maintenance Manual Revision 3 4 COMM SETTINGS MENU The Comm Settings Menu allows the user to configure the Ethernet interface MODBUS TCP slave and two optional RS 485 serial interfaces Comm Settings COMM 1 Settings COMM 2 Settings ModbusTCP Network Settings Troubleshooting COMMx Settings Modbus Slave BaudRate 9600 Parity None Slave ID 42 Byte Order BADC Enable LEDs Yes ModbusTCP Slave Byte Order BADC Master Timeout ms 500 Poll Dly ms 250 Enable LEDs Yes Network Settings DHCP Enabled Yes Hostname Unit 44 1000 Ip Addr

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