Related Manuals for GDS GASMAX CX
Summary of Contents for GDS GASMAX CX
- Page 1 Operation and Maintenance Manual GASMAX CX Single / Dual Channel Gas Monitor GDS Corp. 1245 Butler Road League City, TX 77573 409-927-2980 409-927-4180 (Fax) ww.gdscorp.com ...
- Page 2 GASMAX CX Operation & Maintenance Manual, Revision 1.0 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 SÉCURITÉ, CET ÉQUIPEMENT DOIT ÊTRE UTILISÉ, ENTRETENU ET RÉPARÉ...
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Page 3: Table Of Contents
GASMAX CX Operation & Maintenance Manual, Revision 1.0 CONTENTS SAFETY INFORMATION _______________________________________________ 7 OVERVIEW _________________________________________________________ 8 HARDWARE ________________________________________________________ 9 INSTALLATION _____________________________________________________ 10 Selecting a Location _ _________________________________________________________ 10 Explosion Proof Installation ___________________________________________________ 10 Intrinsically Safe Installation _ __________________________________________________ 10 Mounting the GASMAX CX Instrument Enclosure _ _________________________________ 10 Connecting DC Power & Output Signal Wiring ____________________________________ 11 ... - Page 4 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Normal Operating Mode _ _____________________________________________________ 24 Alarm Operation – ALARM 1, 2 and 3 ___________________________________________ 24 Alarm Operation – FAULT _____________________________________________________ 25 CALIBRATION ______________________________________________________ 26 Calibration Overview _ ________________________________________________________ 26 Calibration Procedure ________________________________________________________ 27 MAINTENANCE _ ____________________________________________________ 29 Normal Maintenance ________________________________________________________ 29 Sensor Replacement – Local Sensors ____________________________________________ 29 Sensor Replacement – Remote Sensors _ _________________________________________ 30 TROUBLESHOOTING_________________________________________________ 32 Toxic Sensor Indicates Fault or Overrange _ _______________________________________ 32 ...
- Page 5 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Comm Settings Menu ________________________________________________________ 39 System Settings Menu _ _______________________________________________________ 40 Diagnostics Menu ___________________________________________________________ 41 NETWORK INTERFACE _____________________________________________ 42 MODBUS Registers __________________________________________________________ 42 SPARE PARTS ____________________________________________________ 50 Sensor Head Accessories _ _____________________________________________________ 51 DRAWINGS AND DIMENSIONS ______________________________________ 52 Page 5 ...
- Page 6 GASMAX CX Operation & Maintenance Manual, Revision 1.0 TABLE OF FIGURES FIGURE 3‐1 GASMAX CX GAS MONITOR ...................... 9 FIGURE 4‐1: GASMAX CX I/O POWER & SIGNAL WIRING ................ 11 FIGURE 4‐2 ETHERNET INTERFACE ....................... 12 FIGURE 4‐3 GASMAX CX OPTIONAL RELAY / MODBUS INTERFACE .............. 12 FIGURE 4‐4: MODBUS WIRING JUNCTION BOX .................... 13 FIGURE 4‐5: MODBUS JBOX LOCATION OPTIONS .................. 14 FIGURE 4‐6: LOCAL SMART TOXIC SENSOR CONNECTION ................ 15 FIGURE 4‐7: REMOTE TOXIC SENSOR TRANSMITTER CONNECTION ............ 16 FIGURE 4‐8: LOCAL SMART BRIDGE SENSOR CONNECTION ................. 17 FIGURE 4‐9 REMOTE INFRARED SENSOR TRANSMITTER ................ 18 FIGURE 4‐10: LOCAL GDS‐IR INFRARED SENSOR .................. 19 ...
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Page 7: Safety Information
GASMAX CX Operation & Maintenance Manual, Revision 1.0 1 SAFETY INFORMATION Important – Read Before Installation Users should have a detailed understanding of GASMAX CX operating and maintenance instructions. Use the GASMAX CX 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 The GASMAX CX gas monitor described in this manual must be installed, operated and maintained in accordance with 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 GASMAX CX is suitable for the intended use. The GASMAX CX is designed and constructed to measure the level of certain gases in ambient air. Accuracy in atmospheres containing steam or inert gases cannot be guaranteed. Always mount the sensor head vertically with the sensor head facing down. However, the GDS‐IR infrared sensor may be mounted vertically or horizontally. Do not paint transmitter or sensor assembly. Do not operate the GASMAX CX 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. Do not expose the GASMAX CX to electrical shock or continuous severe mechanical shock. Protect the GASMAX CX and related sensor assemblies from dripping liquids and high power sprays. Calibrate with known target gas at start‐up and check on a regular schedule, at least every 90 ... -
Page 8: Overview
GASMAX CX Operation & Maintenance Manual, Revision 1.0 2 OVERVIEW The GASMAX CX is a single or dual channel fixed‐point gas monitor designed to provide continuous monitoring of toxic or combustible gases in hazardous areas. Gas values are displayed in calibrated engineering units as well as bar graph or 30‐minute trend graph format. The GASMAX CX supports one or two local or remote mount sensors for toxic or combustible gases. The advanced microcontroller, non‐intrusive magnetic interface and superior full color graphic LCD interface offers rapid setup, simplified operation and enhanced diagnostics not found in previous generation products. On‐board non‐volatile memory retains all configuration data during power interruptions. Two independent 4‐20 mA outputs allow for easy connection to control systems or other alarm instrumentation, and a built‐in Ethernet port allows the GASMAX CX to be easily integrated into a facilities network. Additional output options include 4x alarm relays and dual channel MODBUS slave interfaces. Built‐in user‐prompted calibration makes it easy for one person to perform calibration and maintenance without opening the enclosure or declassifying the area. A battery‐powered real‐time clock and event log allows the GASMAX CX to track calibration and alarm events for later recall on the LCD readout. For toxic gases the GASMAX CX supports a wide range of electrochemical (“echem”) sensors. These sensors use chemical reactions to sense the presence of gases such as hydrogen sulfide, chlorine, sulfur dioxide and many others. Unlike previous generation gas detectors, GASMAX CX sensors contain all the necessary micro‐electronics needed to convert the extremely low level sensor output signals into digital values that are immune to interference and noise. When combined with state‐of‐the‐art digital signal processing and filtering, the GASMAX is capable of gas detecting levels lower than ever before. For combustible gases the GASMAX CX offers three different choices. In addition to traditional catalytic bead (“cat bead”) sensor, the GASMAX CX supports the GDS Corp SmartIR infrared sensor and GDS‐IR infrared sensor as well as the latest generation photoionization detector (PID) sensors for measurement of volatile organic compounds such as benzene or toluene. Page 8... -
Page 9: Hardware
GASMAX CX Operation & Maintenance Manual, Revision 1.0 3 HARDWARE The GASMAX CX is enclosed in a CSA / FM / IECEx certified anodized aluminum explosion proof yellow enclosure designed to protect the electronics and make it easy for workers to identify in industrial environments. The screw‐on front cover is easily removed for installation and maintenance; however, built‐in user interface magnetic switches allow operators and technicians to adjust, calibrate or troubleshoot the GASMAX CX without declassifying the area. Local sensors are contained in a stainless steel sensor head, typically attached to the bottom of the GASMAX CX as shown below. The normal sensor head includes an integrated stainless steel flame arrestor that must be removed for the detection of certain reactive gases such as chlorine or chlorine dioxide. If removed, the GASMAX CX is not certified for use in hazardous areas. See Chapter 13 for drawings and dimensions. ¾” NPT Conduit Entry (2x) Color LCD Display Removable Front Cover Sensor Head & Gas Sensor Optional Splash Guard Figure 3-1 GASMAX CX GAS MONITOR Page 9 ... -
Page 10: Installation
GASMAX CX Operation & Maintenance Manual, Revision 1.0 4 INSTALLATION SELECTING A LOCATION Factors such as prevailing winds, target gas density, potential leak sources, air movement machinery and similar environmental variables are important when selecting a location for the GASMAX CX gas monitor or gas sensor. Even though the GASMAX CX is designed for rugged service, sensors and electronics should be protected from environmental damage due to water, snow, shock, vibration and dirt. In addition, the sensor and / or display should be located such that regular maintenance and periodic sensor replacement can be readily accomplished. While there are no industry standards for gas detector placement, professional tools exist that can simulate leaks or spills and provide excellent guidance for locating gas detectors throughout a facility. EXPLOSION PROOF INSTALLATION GASMAX CX monitors with standard explosion‐proof sensor heads are certified for use in Class 1 Division 1 hazardous areas. Installation in these areas should follow best industry standard practices and all appropriate electrical codes. Generally, these codes require rigid metal conduit, poured seals and other installation elements necessary to ensure safety. In all cases, GDS Corp recommends any GASMAX sensor be mounted vertically with the sensor opening facing down. If there is a possibility that water or other liquid may be present, GDS Corp further recommends the installation of a sensor head Splash Guard (p/n 10‐0205) to protect the sensor from damage. For maximum protection against RF interference or electrical surge, the GASMAX CX enclosure, all remote sensors and interconnecting conduit must be properly grounded. INTRINSICALLY SAFE INSTALLATION The GASMAX CX is not certified for use as an Intrinsically Safe device. MOUNTING THE GASMAX CX INSTRUMENT ENCLOSURE The GASMAX CX standard enclosure is a cast aluminum explosion‐proof (NEMA 7) enclosure as shown in Figure 4‐1. Two channel GASMAX CX units with dual local sensor heads include a “Y” adapter, shown in Figure 4‐2. The GASMAX CX or remote sensor should always be mounted with the sensor head opening facing down. If necessary, a Splash Guard (p/n 10‐0205) should be attached if there is any chance that water or liquid spray could enter the sensor opening from below. Be sure to leave sufficient room (~ 12”) below the sensor head to allow for ambient air circulation and easy access for attachment of a Calibration Cup and / or removal of the sensor head cover for sensor replacement. ... -
Page 11: Connecting Dc Power & Output Signal Wiring
TB1 – 2: Channel 1 4‐20mA Out TO D IS P LA Y TB1 – 3: Channel 2 4‐20mA Out TB1 – 4: Power / Signal Common LO C AL SEN SO R CH 2 CH 1 Figure 4-1: GASMAX CX I/O Power & Signal Wiring NOTE: THE MAXIMUM DISTANCE 4‐20 MA SIGNALS CAN TRAVEL IS DEPENDENT UPON CABLE GAUGE, DC POWER SUPPLY VOLTAGE LEVEL AND INPUT IMPEDANCE OF THE RECEIVING DEVICE. ASSUMING A NOMINAL 24 VDC POWER SUPPLY, 100 OHM LOAD AND MAXIMUM TOTAL LOOP RESISTANCE OF 750 OHMS: #18GA, 0.0064 OHM/FT => 9.6 MILES / 15.5 KM #24GA, 0.026 OHMS/FT => 2.3 MILES / 3.7 KM ... -
Page 12: Connecting To An Ethernet Network
The optional Relay / Modbus board is connected “piggyback” to the back of the GASMAX CX Display Assembly and provides three level alarm relays, a FAULT relay (“K3”), two RS‐485 Modbus RTU serial ports and access to the Digital Input / Remote ACK port. Remote Alarm Acknowledge Relay Wiring: Fault 1 NC Fault 1 Common Modbus Wiring: Fault 1 NO 1 Modbus 1 A Relay 3 NC 2 Modbus 1 B Relay 3 Common 3 Shield Tie Point Relay 3 NO 4 Modbus 2 A Relay 2 NC 5 Modbus 2 B Relay 2 Common Relay 2 NO MODBUS interface 10 Relay 1 NC 11 Relay 1 Common 12 Relay 1 NO Figure 4-3 GASMAX CX Optional Relay / MODBUS Interface Page 12... -
Page 13: Optional Modbus Junction Box
GASMAX CX Operation & Maintenance Manual, Revision 1.0 OPTIONAL MODBUS JUNCTION BOX 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. 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. For MODBUS data signals, GDS Corp recommends 20GA to “A” 24GA twisted shielded cable. Daisy‐chain power distribution “B” may require larger gauge wire since it is critical that the supply voltage for the GASMAX CX at the far end of the string not fall below 12VDC during power‐up. +24 GND A TO GASMAX CX ENCLOSURE +24 GND A Note that while the GASMAX CX has two sets of wiring terminals for MODBUS “A” and “B” signals, daisy‐chain power wiring requires that two wires be installed in the “+24” and “A” “B” “GND” terminals on the GASMAX CX I/O Power Supply board. This ... -
Page 14: Figure 4-5: Modbus Jbox Location Options
GASMAX CX Operation & Maintenance Manual, Revision 1.0 The MODBUS wiring junction box is attached to the GASMAX CX, either on the bottom fitting or one of the side fittings, depending on installation requirements. Specify BOTTOM, LSIDE or RSIDE when ordering (See Fig. 4‐5). “BOTTOM” “LSIDE” Figure 4-5: MODBUS JBOX LOCATION OPTIONS Page 14... -
Page 15: Local Smart Toxic Sensor
GASMAX CX Operation & Maintenance Manual, Revision 1.0 LOCAL SMART TOXIC SENSOR Local Smart toxic sensors are factory installed in a sensor head directly attached to the GASMAX CX enclosure. Local Smart toxic sensors and can be connected to either Channel 1 or Channel 2 sensor inputs on the I/O Power Supply board as shown below. Smart sensors are automatically recognized on power‐up and upload range, calibration and production date information to the GASMAX for use during operation and setup. TO D IS P LA Y LO CAL SEN SO R CH 2 CH 1 Smart TOXIC sensors can be connected to either CH1 or CH2 Figure 4-6: Local Smart Toxic Sensor Connection ... -
Page 16: Connecting A Remote Toxic Sensor Transmitter
GASMAX CX Operation & Maintenance Manual, Revision 1.0 CONNECTING A REMOTE TOXIC SENSOR TRANSMITTER GASMAX CX monitors with remote‐mount toxic sensor transmitters are shipped in two pieces and sensor wiring must be installed by the end user. Remote toxic sensor transmitters connect to the Channel 1 or Channel 2 4‐20mA analog input connections on the Power I/O board as shown below. Remote toxic sensor transmitters use industry standard 4‐20mA signal levels and can therefore be mounted at some distance from the GASMAX CX. GDS Corp recommends a maximum distance of 500 ft. / 150 m using shielded two‐wire cable sized appropriately. GASMAX CX GDS‐49 REMOTE SENSOR TRANSMITTER TO D IS P LAY LO C AL SEN SO R CH 2 CH 1 Remote TOXIC sensor transmitters can be connected to either CH1 or CH2 ... -
Page 17: Local Smart Bridge Sensor
GASMAX CX Operation & Maintenance Manual, Revision 1.0 LOCAL SMART BRIDGE SENSOR Local bridge‐type sensors, including catalytic bead, SmartIR infrared sensors for combustibles and CO2 and photoionization detectors (PID) for volatile organic compounds are factory installed and must be connected to the CH 1 Smart Sensor connector as shown below. TO D IS P LA Y LO CAL SEN SO R CH 2 CH 1 LOCAL SMART BRIDGE‐TYPE SENSORS MUST BE CONNECTED TO CH1 Figure 4-8: Local Smart Bridge Sensor Connection ... -
Page 18: Connecting A Remote Infrared Sensor Transmitter
GASMAX CX Operation & Maintenance Manual, Revision 1.0 CONNECTING A REMOTE INFRARED SENSOR TRANSMITTER GASMAX CX monitors with remote‐mount infrared sensor transmitter for combustibles or CO2 are shipped in two pieces and sensor wiring must be installed by the end user. Remote infrared sensor transmitters connect to the Channel 1 or Channel 2 4‐20mA analog input connections on the Power I/O board as shown below. Remote infrared sensor transmitters use industry standard 4‐20mA signal levels and can therefore be mounted at some distance from the GASMAX CX. GDS Corp recommends a maximum distance of 500 ft. / 150 m using shielded two‐wire cable sized appropriately. GASMAX CX GDS‐50 REMOTE SENSOR TRANSMITTER TO D IS P L A Y LO C AL SEN SO R CH 2 CH 1 ... -
Page 19: Local Gds-Ir Infrared Sensor
GASMAX CX Operation & Maintenance Manual, Revision 1.0 LOCAL GDS‐IR INFRARED SENSOR When the GASMAX CX is configured to include a GDS‐IR Infrared Combustible or CO2 sensor, the IO/Power Supply board is factory modified to make Channel 2 compatible with the sensor’s 4‐20mA input signal. An integrated “zero set” pushbutton and magnetic zero switch is included inside the GASMAX CX enclosure and is used to periodically set the zero point for the GDS‐IR. GASMAX CX with LOCAL GDS‐IR SENSOR GDS‐IR INTERFACE BOARD MOUNTED TO DISPLAY INSIDE GASMAX CX ENCLOSURE LOCAL SENSOR CH 2 CH 1 USE MAGNETIC WAND TO ACTIVATE SET ZERO SWITCH MOUNTED ON GDS‐IR INTERFACE BOARD INSIDE GASMAX CX ENCLOSURE Figure 4-10: Local GDS-IR Infrared Sensor Page 19 ... -
Page 20: Connecting A Remote Gds-Ir Infrared Sensor
GASMAX CX Operation & Maintenance Manual, Revision 1.0 CONNECTING A REMOTE GDS‐IR INFRARED SENSOR GASMAX CX monitors with remote‐mount GDS‐IR sensors are shipped in two pieces and sensor wiring must be installed by the end user. GDS‐IR sensors can be mounted up to 500 feet from the GASMAX display. Cable used should be three‐wire stranded with foil shield. GDS Corp recommends Belden B8771. The cable shield must be connected to an earth ground at ONE END ONLY. In this configuration the zero‐ set pushbutton is located in the GDS‐IR remote mount junction box. GASMAX CX GAS MONITOR REMOTE GDS‐IR SENSOR TO DISPLAY LOCAL SENSOR CH 2 CH 1 RED: +18 ‐ 30VDC Power CUSTOMER‐SUPPLIED 4‐CONDUCTOR SHIELDED WIRING BLU: 4‐20mA Analog Out #18 GA OR LARGER RECOMMEND BLK: Power Common WHT: Hardware Zero Figure 4-11: Remote GDS-IR Connection Page 20... -
Page 21: Connecting An External 4-20Ma Input Device
GASMAX CX Operation & Maintenance Manual, Revision 1.0 CONNECTING AN EXTERNAL 4‐20MA INPUT DEVICE The GASMAX CX supports two general purpose, non‐isolated 4‐20mA inputs as shown below. The amount of voltage and current available for the remote 4‐20mA device is determined by the GASMAX DC supply connected to TB1. Both channels support local calibration if necessary; if the devices are pre‐calibrated, or are calibrated at the source, the calibration feature on each channel can be disabled. INPUT: TB2 – 1: +24VDC Excitation Out TB1 – 2: Channel 1 4‐20mA Input TO D IS P LA Y TB1 – 3: Common TB1 – 4: Channel 2 4‐20mA Input OUTPUT: TB1 – 1: +24VDC Input TB1 – 2: Channel 1 4‐20mA Out LO C AL SEN SO R TB1 – 3: Channel 2 4‐20mA Out CH 2 ... -
Page 22: Setup And Operation
GASMAX CX Operation & Maintenance Manual, Revision 1.0 5 SETUP AND OPERATION 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. When not viewing any of the user menus, pressing the NEXT key momentarily causes the GASMAX CX display to sequence between DUAL CHANNEL DATA DISPLAY, CHANNEL 1 TREND DISPLAY, CHANNEL 2 TREND DISPLAY, CHANNEL 1 DATA DISPLAY and CHANNEL 2 DATA DISPLAY as shown below. If only one channel is enabled, the dual channel display mode and corresponding data and trend screens are not included in the rotation. Figure 5-1: GASMAX CX Display Screen Sequence ... -
Page 23: Display Screens
GASMAX CX Operation & Maintenance Manual, Revision 1.0 DISPLAY SCREENS The DATA display screen shows a single channel’s information. The current value is shown in calibrated engineering units. A horizontal bargraph tracks the current value and shows the Alarm 1 and Alarm 2 values in graphical form. The user‐programmable Engineering Units (“Eunits”) and programmable Tag Name (“Measurement Name”) text strings are shown below the real‐time reading. If the channel is in Alarm 1, the background color changes to YELLOW, and if the channel is in Alarm 2, the background color changes to RED. “UP/RESET” “NEXT” Current Reading Programmable Engineering Units Programmable Tag Name “DN/CAL” “EDIT” Figure 5-2 GASMAX DATA DISPLAY Below the LCD display, two LEDs indicate the status of the Ethernet or serial MODBUS communications channels. The TREND display shows a graph of the most recent 30 minute interval for the channel value. The graph is scaled to match the channels zero and span settings and shows the trend line, real‐time value and Alarm 1 and Alarm 2 settings as Yellow and Red horizontal lines. Current Reading Last 30 minute trend Alarm 2 Level Alarm 1 Level ... -
Page 24: Initial Setup
GASMAX CX Operation & Maintenance Manual, Revision 1.0 INITIAL SETUP Once installed, apply power to the GASMAX CX and verify that the LCD display is active. Certain sensors may initially indicate off‐scale high or low values, but should quickly return to zero if no target gas is present. During this warm‐up delay period, the 4‐20mA output is held at 4.0 mA to eliminate false alarms in any receiving devices. Warm‐up delay is one of the user‐adjustable parameters. Once operational, the user should verify the following settings prior to initial calibration: Local time and date: Check date value and adjust time for proper time zone. Tag name or Engineering Units settings: Edit values as necessary. CAL SPAN GAS value: Set to match concentration of calibration gas cylinder. CAL MARKER value: Adjust desired output mA during calibration. ALARM 1, ALARM 2, ALARM 3 settings: Set for desired levels. NOTE: If relays are not installed, GASMAX CX programmable alarm levels affect operation of display color only (Sec 7‐3). Allow the GASMAX CX to stabilize for at least four hours, preferably overnight if possible. This will allow all sensors to reach stable equilibrium with respect to environmental conditions such as ambient temperature, humidity, and barometric pressure as well as applied “reference” and “counter” voltages generated by the GASMAX CX electronics. At this point, the GASMAX CX can be calibrated and made operational. NORMAL OPERATING MODE During normal operation, the GASMAX display shows the current gas reading in direct calibrated engineering units. If the reading goes above the Alarm 1 or Alarm 2 values, the display will change color and flash, and the internal relays, if installed and programmed properly, will activate. The 4‐20mA outputs will transmit values that represent the % of scale shown on the display. If the sensor malfunctions, or is removed, the display will turn red and the message FAULT will appear on the screen. ALARM OPERATION – ALARM 1, 2 AND 3 Each channel can be programmed for up to three independent alarm levels, and can be set to alarm ABOVE the target value for BELOW the target value. All programming is done in engineering units that correspond to the channels ZERO and SPAN settings. Alarm processing will trigger an alarm condition when the input exceeds the programmed value, and includes hysteresis to keep the alarm from rapidly switching ON and OFF if the input remains close to the programmed alarm value. NOTE: ALARM RELAYS ARE NORMALLY TRIGGERED IF EITHER CHANNEL 1 OR CHANNEL 2 ALARM ... -
Page 25: Alarm Operation - Fault
GASMAX CX Operation & Maintenance Manual, Revision 1.0 NOTE: IF THE OPTIONAL ALARM RELAYS ARE NOT INSTALLED, ALARM SETTINGS AFFECT THE OPERATION OF THE FRONT PANEL DISPLAY ONLY. SEPARATE ALARM SETTINGS MAY NEED TO BE PROGRAMMED IN THE 4‐20MA RECEIVING DEVICE. ALARM OPERATION – FAULT FAULT is typically used to indicate FAULT conditions that suggest sensor failure or “out of measurement range” conditions. Page 25 ... -
Page 26: Calibration
GASMAX CX Operation & Maintenance Manual, Revision 1.0 6 CALIBRATION CALIBRATION OVERVIEW Calibration is critically important to ensure correct operation of the GASMAX CX. The 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. During CAL MODE zero and span, the sensor output is disconnected and the GASMAX CX transmits a fixed mA value, called the CAL MARKER, to notify the receiving device that a calibration is in progress. During the following CAL PURGE DELAY time, the GASMAX CX transmits a fixed 4.0 mA signal to prevent external alarms during calibration. In the case of local or remote Oxygen sensors, during CAL PURGE DELAY the output simulates a typical atmospheric reading of 20.8%. CAL MODE automatically exits if no keystrokes are detected after 5 minutes. Follow these GASMAX CX calibration guidelines: Calibration accuracy is only as good as the calibration gas accuracy. GDS Corp calibration gases are traceable to NIST (National Institute of Standards and Technology). Never use calibration gas that has passed its expiration date. Check the SPAN GAS VALUE setting and make sure it matches the calibration gas. (See Fig. 6‐2) Always use a GDS Corp calibration cup that completely surrounds the sensor head. Be sure to use ZERO AIR, a mixture of 21% oxygen and 79% nitrogen, as a zero reference unless you are certain that no target gas exists in the area. Ambient gas may result in an ‘elevated zero’ condition that will cause a FAULT to occur once the ambient gas is no longer present. Always calibrate a new sensor before depending on the device for personnel or equipment safety Calibrate on a regular schedule. GDS Corp recommends a full calibration every 3 months, with periodic ‘bump tests’ on a more frequent basis to ensure that the sensor has not been affected by temperature extremes or the presence of incompatible gases. ... -
Page 27: Calibration Procedure
GASMAX CX Operation & Maintenance Manual, Revision 1.0 CALIBRATION PROCEDURE Before beginning calibration, make sure you have the following items: A cylinder of calibration gas, fixed flow regulator and an appropriate calibration cup connected to the regulator via a length of flexible tubing. If necessary, a cylinder of ‘zero air’ may be necessary if the absence of target gas cannot be confirmed. GDS Corp recommends a flow rate of 0.5 liters / minute for standard gases and a flow rate of 1.0 liters / minute for highly reactive gases such as chlorine or chlorine dioxide. Flexible Tubing Fixed Flow Regulator Cylinder of Calibration Gas Calibration Cup To calibrate a GASMAX CX detector: 1. For dual channel units, press the NEXT key until that the DATA Display screen for the desired channel is shown. 2. To enter CAL MODE, press the DOWN / CAL key and within 5 seconds press the EDIT key. 3. The screen will display an APPLY ZERO message. Using the setup shown in Fig. 5‐1, apply clean ZERO air unless it can be guaranteed that no target gas is present. After the reading stabilizes, press the EDIT key to complete the ZERO calibration. 4. If the ZERO CAL SUCCESSFUL message is displayed, an APPLY SPAN message will appear. Apply the correct SPAN gas. After the reading is stable, (approximately 1 minute) press the EDIT key to Page 27 ... -
Page 28: Figure 6-1: Calibration Flowchart
GASMAX CX Operation & Maintenance Manual, Revision 1.0 complete the SPAN GAS calibration. If the SPAN calibration is successful, the display flashes REMOVE CAL GAS and starts the CAL PURGE delay. 5. Immediately shut off the regulator and remove the calibration cup. At the end of the CAL PURGE delay, the GASMAX EC output is re‐enabled and the unit is fully operational. The flow chart shown in Figure 5‐2 illustrates the above procedure. UP, CAL, NEXT & EDIT labels indicate keystrokes using the magnetic wand. ZERO or SPAN calibration will fail if the readings exceed built‐in limits for maximum allowable zero or minimum allowable span. NOTE: A CAL MODE INFO SCREEN IS AVAILABLE TO VIEW CERTAIN CAL MODE PARAMETERS DURING CALIBRATION. HOLD THE UP KEY FOR 5 SECONDS DURING CAL MODE TO DISPLAY THIS SCREEN. Figure 6-1: Calibration Flowchart... -
Page 29: Maintenance
GASMAX CX Operation & Maintenance Manual, Revision 1.0 7 MAINTENANCE NORMAL MAINTENANCE Normal maintenance for the GASMAX CX primarily involves periodic calibration on standard intervals. GDS Corp recommends calibration at least every three months, or more often if temperature extremes, vibration, the presence of incompatible gases or other environmental factors may accelerate the deterioration of the sensor element. Calibration should also include inspections for clogged or wet sensor heads, cracked or damaged enclosures and water incursion inside conduit or junction boxes. SENSOR REPLACEMENT – LOCAL SENSORS If a sensor shows FAULT, does not respond to gas or can no longer be calibrated, it should be replaced. GASMAX CX monitors use GDS Corp type 10‐98XX toxic or combustible sensors, where the XX is the gas type, or GDS‐IR infrared sensors. For toxic or combustible sensors, the range value should also be specified when ordering replacement sensors. For example, a replacement H2S sensor for 0‐100 ppm would be “10‐9815‐R0100”. To replace a GASMAX local sensor: 1. Declassify the area or remove power to the GASMAX CX. 2. Unscrew the sensor head cover. If unable to open the cover by hand, use a Sensor Head Replacement Tool (p/n 10‐0187). 3. Remove the old sensor by pulling straight down. NOTE: DO NOT TRY TO UNSCREW THE SENSOR. PULL STRAIGHT DOWN! 4. Carefully install the replacement sensor by aligning the arrow on the sensor with the arrow engraved on the sensor head. Push straight up until the sensor connector seats firmly into the sensor connector. 5. Reinstall the sensor head cover by CAREFULLY screwing the cover onto the sensor head. NOTE: IF THE SENSOR FALLS OUT OF THE SOCKET DURING THIS STEP, IT CAN BE DAMAGED. USE CAUTION WHEN REINSTALLING THE COVER. ... -
Page 30: Sensor Replacement - Remote Sensors
GASMAX CX Operation & Maintenance Manual, Revision 1.0 Figure 7-1: GASMAX Sensor Replacement Local Smart Sensors are automatically recognized by the GASMAX CX and the Smart Sensor identification screen should appear immediately after the installation of a local Smart Sensor. If the sensor is the same gas type as was previously installed, the sensor’s calibration data will be uploaded into the GASMAX CX. All other parameters stored in the GASMAX CX will be retained. GASMAX CX units can be reconfigured for different sensors by simply installing a different type compatible sensor. If a new sensor TYPE is installed, the Smart Sensor identification screen will appear, followed by the ERROR CODE 01 message and the user will be given the opportunity to confirm the new sensor type. If the user activates the EDIT key, all data stored in the new sensor’s database – including range, tag name, cal span value, engineering units and alarm levels – will replace the current settings. SENSOR REPLACEMENT – REMOTE SENSORS To replace a GASMAX remote sensor: 1. Declassify the area or remove power to the GASMAX CX. 2. Unscrew the sensor head cover. If unable to open the cover by hand, use a Sensor Head Replacement Tool (p/n 10‐0187). 3. Remove the old sensor by pulling straight down. NOTE: DO NOT TRY TO UNSCREW THE SENSOR. PULL STRAIGHT DOWN! Page 30... - Page 31 GASMAX CX Operation & Maintenance Manual, Revision 1.0 4. Carefully install the replacement sensor by aligning the arrow on the sensor with the arrow engraved on the sensor head. Push straight up until the sensor connector seats firmly into the sensor connector. 5. Reinstall the sensor head cover by CAREFULLY screwing the cover onto the sensor head. NOTE: IF THE SENSOR FALLS OUT OF THE SOCKET DURING THIS STEP, IT CAN BE DAMAGED. USE CAUTION WHEN REINSTALLING THE COVER. 6. At the GASMAX CX, activate the Main Menu, open the Sensor Information page and select Install New Sensor. This will reset the Sensor Life settings and tell the GASMAX that a new sensor is available. Page 31 ...
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Page 32: Troubleshooting
GASMAX CX Operation & Maintenance Manual, Revision 1.0 8 TROUBLESHOOTING TOXIC SENSOR INDICATES FAULT OR OVERRANGE Certain toxic sensors indicate off‐scale low or high at power up and quickly drift towards zero. This is normal behavior. Toxic sensors showing constant FAULT: If local, remove sensor and examine for moisture or discoloration. Replace sensor if wet or discolored. If remote, check sensor cable and junction box for moisture or standing water. Remove sensor and examine for moisture or discoloration. FAULT indication generally indicates sensor useful life is exhausted. Toxic sensors left unpowered for more than 3 months are subject to accelerated degradation and may demonstrate a permanent loss of sensitivity. TOXIC SENSOR WILL NOT CALIBRATE 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. BRIDGE SENSOR INDICATES FAULT OR OVERRANGE Catalytic bead combustible sensors generally indicate off‐scale high at power up and quickly drift towards zero as they reach operating temperature. This is normal behavior. Combustibles sensors showing constant OVERRANGE may have defective bead. If remote, check wiring for correct excitation voltage at sensor. Replace sensor. BRIDGE SENSOR WILL NOT CALIBRATE Sensor reading during zero calibration exceeds limits – readjust SENSOR BALANCE to reset zero if possible. If not, sensor is defective and should be replaced. ... -
Page 33: Receiving Device And Gasmax Displayed Values Don't Match
GASMAX CX Operation & Maintenance Manual, Revision 1.0 RECEIVING DEVICE AND GASMAX DISPLAYED VALUES DON’T MATCH Check that zero and full scale range values match between GASMAX and receiving device (controller). Use DIAGNOSTICS menu to force GASMAX CX output to 12mA (1/2 scale) and verify appropriate half‐scale reading on controller. Check for high impedance shorts to ground on 4‐20mA wiring. If 4‐20mA output is off‐scale low or high and cannot be adjusted using DIAGNOSTICS mode, IO/Power Supply board may be defective and should be replaced. CONTROLLER MODBUS DATA INCORRECT Verify the MODBUS master is requesting data from registers 31001 for CH 1, 31002 for CH 2. 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. Verify that the GASMAX MODBUS address matches the address programmed into the controller’s channel configuration. CONTROLLER SHOWING MODBUS COMM ERROR Check for incorrect MODBUS polarity (swap “A” and “B” if unsure; no damage will occur). Verify that MODBUS master is requesting data from correct MODBUS address. Verify that MODBUS master is requesting correct registers: 31001 for CH 1, 31002 for CH 2. Verify that there are no other MODBUS slave devices with identical MODBUS address. GASMAX DISPLAY BLANK Verify DC power at IO/Power Supply board, TB1, terminals 1 (+24) and 4 (Gnd). ... -
Page 34: Specifications
GASMAX CX Operation & Maintenance Manual, Revision 1.0 9 SPECIFICATIONS Model GASMAX CX Single / Dual Channel Gas Monitor Power Input 10‐30VDC at < 10 watts with relay board. Additional power required for Extended Temp & GDS‐IR option. Display Full color LCD with engineering units, bargraph and 30‐minute trend Channel One Digital input for GDS Corp 10‐98xx Smart Toxic Sensors Input Bridge input for GDS Corp 10‐98xx Catalytic Bead, SmartIR or PID sensors Analog 4‐20mA input Channel Two Digital input for GDS Corp 10‐98xx Smart Toxic Sensors Input Analog 4‐20mA input Accuracy +/‐ 5% of full scale (typical) Standard Dual three‐wire 4‐20mA current source outputs with fault and overrange indication. Output Maximum loop resistance is 750 ohms with standard 24VDC supply Optional Relay / MODBUS interface with 4x 5A SPDT programmable alarm relays Output Dual channel MODBUS interface Temperature Electronics ‐40°C to +60°C. See Sensor Manual for additional details Memory On‐board non‐volatile memory retains all user settings ... -
Page 35: User Menus
GASMAX CX Operation & Maintenance Manual, Revision 1.0 10 USER MENUS 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 Output Menu – contains settings that control the four optional Alarm Outputs Relay 1 →... -
Page 36: Alarm Outputs Menu
GASMAX CX Operation & Maintenance Manual, Revision 1.0 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 → All three relay outputs are identical and can be set to respond to Relay 2 → Relay 3 → channel 1 or channel 2 events. The fault relay is always dedicated to Relay x Alarm 1 Alarm 1, 2, 3 and Fault – Determines which channel or combination of Alarm 2 Alarm 3 channels can activate the relay. Options are “Off”, “Ch1”, “Ch2”, “Ch1 and Fault Ch2”, and “Ch1 or “Ch2”. ... -
Page 37: Channel Settings Menu
GASMAX CX Operation & Maintenance Manual, Revision 1.0 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 All three relay outputs are identical and can be set to respond to channel 1 or channel Channel 1 → Channel 2 → 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 → Alarm 2 → Alarm 3 → Alarm X menu (all three alarm setting menus are identical) Fault Alarm →... -
Page 38: Figure 10-4: Channel Settings Menu Tree (2)
GASMAX CX Operation & Maintenance Manual, Revision 1.0 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 Temp. Comp. minus 40C to +60C. Gain and offset values are linearly interpolated Temp Gain Offset 1.00 +0.00 between points by the internal microprocessor. 1.00 +0.00 NOTE: These values are typically set by the sensor manufacturer and 1.00 +0.00 1.00 +0.00 should not be changed. 1.00 +0.00 1.00 +0.00 1.00 +0.00 1.00 +0.00 1.00 +0.00 Configure Menu ... -
Page 39: Comm Settings Menu
GASMAX CX Operation & Maintenance Manual, Revision 1.0 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 X Menu (both comm port setting menus are identical) COMM 1 Settings → Type (“Modbus Slave”) determines whether the MODBUS port is a master COMM 2 Settings → ModbusTCP → or slave. Network Settings → Baud Rate – Sets the baud rate for the serial port. Options are 9600, → Troubleshooting 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. COMMx Settings Enable LEDs – If YES, front panel LEDs indicate MODBUS transmission. ... -
Page 40: System Settings Menu
GASMAX CX Operation & Maintenance Manual, Revision 1.0 SYSTEM SETTINGS MENU The Comm Settings Menu allows the user to configure the Ethernet interface, MODBUS/TCP slave and two optional RS‐485 serial interfaces. System Configure Menu Version v1.00 Date & Time – Sets the system date and time. Used for display and event Configure → Digital Input → log entries. View Event Log → Clear Event Log → Warm Up Delay – Sets length of time (in minutes) from power on to output View Sensor Life → signals active. During Warmup Delay the 4‐20mA outputs are set to 4mA. Cal Purge Delay ‐ Sets length of time (in minutes) that outputs are disabled following a zero or span calibration Configure Block Negative – If YES, blocks screen from showing negative values. ... -
Page 41: Diagnostics Menu
GASMAX CX Operation & Maintenance Manual, Revision 1.0 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. WARNING – ENTERING DIAGNOSTICS MODE DISABLED ALARM Alarms will not Be processed. -
Page 42: Network Interface
GASMAX CX Operation & Maintenance Manual, Revision 1.0 11 NETWORK INTERFACE MODBUS REGISTERS The GASMAX CX features a full complement of user‐accessible MODBUS registers that can provide a complete snapshot of the gas detector configuration. This includes all real‐time data, preset zero, span and calibration values and user‐programmable text. 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 43 GASMAX CX Operation & Maintenance Manual, Revision 1.0 SR 2 State 32021 4 N/A True if relay #2 active SR 3 State 32022 4 N/A True if relay #3 active FR State 32023 4 N/A True if fault relay active Warmup 32025 4 N/A True if unit in warm‐up SR 1 Flashing 32026 4 N/A True if relay #1 flashing SR 2 Flashing ...
- Page 44 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Ch 2 I/O 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 Alarm Reset 40001 ...
- Page 45 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Gateway IP 40074 3 N/A Ethernet port: xxx.xxx.xxx.xxx Modbus TCP Byte Order 40080 3 N/A MODBUS/TCP function Modbus TCP Timeout 40081 3 N/A MODBUS/TCP timeout (mSec) Modbus TCP Poll Delay 40082 3 N/A MODBUS/TCP poll delay (mSec) Save Config ...
- Page 46 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Ch 1 Preamp gain 40433 3 N/A Contact factory Ch 2 Preamp gain 40434 3 N/A Contact factory Ch 1 Cal Zero 42001 3 N/A Modbus 32 bit IEEE 754 Floating Pt Ch 1 Cal Span 42003 3 N/A Modbus 32 bit IEEE 754 Floating Pt Ch 1 Zero Value 42005 3 N/A Modbus 32 bit IEEE 754 Floating Pt Ch 1 Span Value 42007 ...
- Page 47 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Ch 1 Data From 43031 3 N/A Selection Ch 1 Min Raw 43032 3 N/A Binary (800) Ch 1 Max Raw 43033 3 N/A Binary (4000) Ch 1 Remote ID 43034 3 N/A Binary Ch 1 Interface 43035 3 N/A Binary Ch 1 Byte Order ...
- Page 48 GASMAX CX Operation & Maintenance Manual, Revision 1.0 Ch 2 Alarm 1 Latch 43201 3 N/A False = NO, True = YES Ch 2 Alarm 1 Trip 43202 3 N/A False = HIGH, True = LOW Ch 2 Alarm 1 On Delay 43203 3 N/A Activation delay in seconds Ch 2 Alarm 1 Off Delay 43204 3 N/A Deactivation delay in minutes Ch 2 Alarm 1 Hysteresis 43205 3 N/A Percent of scale ...
- Page 49 GASMAX CX Operation & Maintenance Manual, Revision 1.0 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 Ch 2 Temp Comp ‐40 43299 3 N/A 32 bit FP Gain, 32 bit FP Offset Ch 2 Temp Comp ‐30 43303 3 N/A 32 bit FP Gain, 32 bit FP Offset Ch 2 Temp Comp ‐20 ...
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Page 50: Spare Parts
Display Assembly: 10‐0387 Display Board 10‐0388 Relay / MODBUS Board I/O Power Supply Board 10‐0390 Power / I/O Board Yellow Enclosure: 10‐0160 GASMAX Enclosure Sensor Head Assembly: 10‐0247 Toxic or Bridge Direct (Type 1‐2) 10‐0247F Toxic Direct / Reactive Gas (Type 3‐4) 10‐0248 Toxic Sensor Transmitter (Type 20‐21) 10‐0248F Toxic S‐T / Reactive Gas (Type 22‐23) Figure 12-1: GASMAX CX + Local Sensor Spare Parts Page 50... -
Page 51: Sensor Head Accessories
GASMAX CX Operation & Maintenance Manual, Revision 1.0 Sensor Head Assembly (See list above): Sensor Head Base Sensor: 10‐98xx (Toxic, combustible, SmartIR, PID) Sensor Head Cover Figure 12-2: GASMAX Sensor Head SENSOR HEAD ACCESSORIES Sensor Head Splash Guard 10‐0198 Splash Guard (Fits all sensor heads Sensor Head Flow Cell 10‐0205 Flow Cell (1/8” NPT compression fittings) Splash Guard Flow Cell Figure 12-3: GASMAX Sensor Head Splash Guard & Flow Cell ... -
Page 52: Drawings And Dimensions
GASMAX CX Operation & Maintenance Manual, Revision 1.0 13 DRAWINGS AND DIMENSIONS 5.25” 5.0” 7.75” Figure 13-1 GASMAX CX DIMENSIONS Page 52... -
Page 53: Figure 13-2 Gasmax Cx Remote Sensor Transmitter Dimensions
GASMAX CX Operation & Maintenance Manual, Revision 1.0 4.25” 5.0” 7.75” Figure 13-2 GASMAX CX REMOTE SENSOR TRANSMITTER DIMENSIONS Page 53 ... - Page 54 GDS Corp. 1245 Butler Road League City, TX 77573 409-927-2980 409-927-4180 (Fax) ww.gdscorp.com ...