Model CXT-IR Operator’s Installation and Instruction Manual Covers all Model CXT-IR Sensors DETCON, Inc. 4055 Technology Forest Blvd, Suite 100 The Woodlands, Texas 77381 Ph.281.367.4100 / Fax 281.298.2868 www.detcon.com May 29, 2014 • Document # 3822 • Revision 1.
Model CXT-IR This page left intentionally blank Model CXT-IR ii
Model CXT-IR Table of Contents 1. 2. 3. 4. 5. 6. 7. Introduction ............................................................................................................................................... 1 1.1 Description .......................................................................................................................................... 1 1.2 Modular Design ......................................................................................................................
Model CXT-IR 8. 9. CXT-IR Sensor Warranty ...................................................................................................................... 40 Appendix................................................................................................................................................... 41 9.1 Specifications .................................................................................................................................... 41 9.1.1 System Specifications ....
Model CXT-IR 1. Introduction 1.1 Description Detcon Model CXT-IR combustible gas sensors are non-intrusive “Smart” sensors designed to detect and monitor combustible hydrocarbon gases in the air with a detection range of 0-100% LEL (Lower Explosive Limit). The sensor features an LED display of current reading, fault and calibration status.
Model CXT-IR Figure 1 Sensor Cell Construction Principle of Operation The target gas diffuses through a sintered stainless steel flame arrestor and into the volume of the sample gas optical chamber. An alternating miniature lamp provides a cyclical IR radiation source, which reflects through the optical gas sample chamber and terminates at the two pyroelectric detectors.
Model CXT-IR 1.
Model CXT-IR Figure 4 ITM Circuit Functional Block Diagram detcon inc. LED Display MODEL Program Switch #1 CXT- IR Program Switch #2 LEL Sensor Housing Bottom Locking Set-Screw Figure 5 Sensor Assembly Front View 1.2.2 Field Replaceable Sensor Detconꞌs infrared gas sensors are field proven, plug-in sensors with over-sized gold-plated connections that eliminate corrosion problems.
Model CXT-IR The CXT-IR sensor utilizes a transceiver radio, based on the IEEE 802.15.4 standard. The transceiver operates at 2.4 GHz using DSSS encoding for robustness in noisy conditions and to resist jamming. DSSS transmits data across a wider frequency range than the actual frequency range required for the information. This operation minimizes cross talk and interference from other transceivers and is less susceptible to noise from other sources. The IEEE 802.15.
Model CXT-IR Figure 7 Smart Battery Pack Quad Battery Charger (Optional) Detcon’s Smart Battery Pack can be charged as needed using Detcon’s optional Quad Battery Charger which can charge up to four battery packs at one time. The Quad Battery Charger comes with a plug-in AC/DC adapter that plugs into a standard 100-240VAC outlet for power. The DC end of the adapter plugs into the DC power jack of the charger providing 24VDC.
Model CXT-IR This option offers a smaller foot print, but provides less run time than Detcon’s Smart Battery Pack. The CXTIR sensors will operate up to 60 days before battery replacement is needed. The addition of Detconꞌs Stainless Steel Mini Condulet provides Class I Div 1, Group B, C, and D ratings. Figure 9 Tri C Lithium Battery Holder CXT-IR Instruction Manual Rev. 1.
Model CXT-IR 2. Installation 2.1 Hazardous Locations Installation Guidelines for Safe Use 1. Install the sensor only in areas with classifications matching the approval label. Follow all warnings listed on the label. Figure 10 Approval Label 2. Do not remove the junction box cover while in the classified are unless it is conformed the there is no explosive gas levels in the area. 3. A good ground connection should be verified between the sensor’s metal enclosure and the junction box.
Model CXT-IR 2.2 Sensor Placement Selection of sensor location is critical to the overall safe performance of the product.
Model CXT-IR The sensor should not be positioned where it may be sprayed or coated with surface contaminating substances. Painting sensor assemblies is prohibited. Although the sensor is designed to be RFI resistant, it should not be mounted in close proximity to highpowered radio transmitters or similar RFI generating equipment. When possible mount in an area void of high wind, accumulating dust, rain, or splashing from hose spray, direct steam releases, and continuous vibration.
Model CXT-IR 8-32 tapped ground point Spacer 23" Typ. Use spacers to move sensor assembly away from wall at least 0.5". 4 NPT Port 4" mounting holes mounting surface) Spacer 3 1 Wall (or other 5.5" ITM Assembly Splash Guard Adapter Splash Guard 9.5" 7.45" Figure 11 CXT-IR Sensor with Smart Battery Pack Mounting Dimensions CXT-IR Instruction Manual Rev. 1.
Model CXT-IR 3.64" 4.1" 3 4 NPT Port 22"Typ. 3.45" Ø0.4 X 0.475" mounting holes Mini Condulet with Battery Holder and Batteries 6-32 tapped ground point ITM Assembly Splash Guard Adapter Splash Guard Figure 12 CXT-IR Sensor with C-Cell Batteries 2.5 Electrical Installation The CXT is designed to be battery operated, and normally will not have external cabling or wiring. If the sensor requires external wiring, the sensor assembly should be installed in accordance with local electrical codes.
Model CXT-IR If a conduit run exists, a drain should be incorporated. The drain allows H 2 O condensation inside the conduit run to safely drain away from the sensor assembly. The electrical seal fitting is required to meet the National Electrical Code per NEC Article 500-3d (or Canadian Electrical Code Handbook Part 1 Section 18-154). Requirements for locations of electrical seals are covered under NEC Article 501-5.
Model CXT-IR 4. Replace the junction box cover after Initial Start Up. 24VDC Return To External 24V Power - Red Black Wht/Blk Wht/Brn + To Sensor Figure 13 Terminal Interconnect for Smart Battery Pack NOTE A 6-32 or 8-32 threaded exterior ground point is provided on most junction boxes for an external ground. If the Sensor Assembly is not mechanically grounded, an external ground strap must be used to ensure that the sensor is electrically grounded. 2.6 Initial Start Up 2.6.
Model CXT-IR Initial Operational Tests After a warm up period of 1 hour (or when zero has stabilized), the sensor should be checked to verify sensitivity to the target gas.
Model CXT-IR 3. Operation The Operator Interface of the Model CXT Series gas sensors is accomplished via two internal magnetic switches located to either side of the LED display (Figure 15). The two switches, labeled PGM1 and PGM2, allow for complete calibration and configuration, eliminating the need for area de-classification or the use of hot permits. Figure 14 Magnetic Programming Tool The magnetic programming tool (Figure 14) is used to operate the magnetic switches.
Model CXT-IR 3.1 Operator Interface The operating interface is menu-driven by the two magnetic program switches located under the target marks of the sensor housing. The two switches are referred to as PGM1 and PGM2. The menu list consists of three menu items that include sub-menus; normal operation, calibration mode and, program mode. Normal Operation Concentration Reading is displayed once every 10 seconds. Calibration Mode AutoZero AutoSpan Program Mode View Sensor Status Mp App ##.## CP App ##.
CXT-IR Instruction Manual Rev. 1.6 Temperature ##C Sensor Life ###% Last Cal ## Days Range ### Network ID ## RF Channel ## Serial N. ##.##.## Modbus ID #### RF SW ##.## RF App ##.##.## CP App ##.## MP App ##.
Model CXT-IR 3.2 Normal Operation In normal operation, the ITM Display will be blank and will display the gas reading once every 10 seconds for about 2 seconds (normally appear as 0). At any time swiping a magnet across either PGM1 or PGM2 will cause the ITM to display the units and gas type (i.e. % LEL or PPM H2S). If the sensor is actively experiencing any diagnostic faults, a swipe of the magnet will cause the display to scroll the fault condition. Refer to Section 3.
Model CXT-IR NOTE The "◄" prompt will show that the magnetic switch is activated during the 3 second hold period. NOTE Upon entering calibration mode, the Modbus™ status register bit 14 is set to signify the sensor is in-calibration mode. This bit will remain set until the program returns to normal operation. c) The ITM will display the following sequence of text messages as it proceeds through the AutoZero sequence: Zero Cal . . . Setting Zero . . .
Model CXT-IR concentration is 50% of range. If a span gas containing the recommended concentration is not available, other concentrations may be used as long as they fall between 5% and 95% of range. However, any alternate span gas concentration value must be programmed via the Set AutoSpan Level menu before proceeding with AutoSpan calibration. Follow the instructions a) through f) below for AutoSpan calibration. a) Verify that the AutoSpan level is equal to the calibration span gas concentration.
Model CXT-IR 3.4 Program Mode Program Mode provides a View Sensor Status menu to check operational and configuration parameters. Program Mode also provides for adjustment of the AutoSpan Level, Gas Factor, Gas Type and Range, and Serial ID.
Model CXT-IR From the View Sensor Status text scroll, hold the magnet over PGM1 or PGM2 until the arrow prompt appears and continue to hold the magnet in place for an additional 3 to 4 seconds (until the display starts to scroll Status Is). The display will scroll the complete list of sensor status parameters sequentially. When the status list sequence is complete, the ITM will revert to the View Sensor Status text scroll.
Model CXT-IR 3.4.4 Set Gas Factor Because of the CXT-IR sensorꞌs almost universal response to combustible hydrocarbon gases, the CXT-IR sensor can be configured and calibrated to detect a variety of combustible gases. The detected gas is referred to as the "target gas" and the span calibration gas is referred to as the "cal gas". In cases where the cal gas is different from the target gas, the Set Gas Factor menu function is used to maintain accuracy.
Model CXT-IR displayed. Hold the magnet over PGM2 for 3 seconds to accept the new value. The display will scroll Factor Saved, and revert to Set Gas Factor text scroll. Move to another menu item by executing a momentary hold, or, return to normal operation via automatic timeout of about 15 seconds (the display will scroll Set Gas Factor four times and then return to normal operation). 3.4.
Model CXT-IR desired ID is displayed. Hold the magnet over PGM2 for 3 to 4 seconds to accept the new value. The display will scroll Channel Saved, and revert to Set RF Channel text scroll. Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic timeout of about 15 seconds (the display will scroll Set RF Channel four times and then return to Normal Operation). 3.4.8 Set Modbus™ ID The CXT-IR sensor can be polled serially via RS-485 Modbus™ RTU.
Model CXT-IR 4. Modbus™ TM Communications Modbus™ communication with a CXT Sensor is normally accomplished using another wireless transceiver such as the RXT-320 which is connected through a RS-485 interface to a Modbus™ master control unit. The control unit can then access the Modbus™ registers within the CXT to obtain readings and status of the sensor.
Model CXT-IR Table 2 Exception Codes Exception Code Name 01 Illegal Function 02 Illegal Data Address Meaning Unsupported function code. Only 03, 06 and 16 are supported. Invalid register address detected. If any request for registers outside of the valid register address for the CXT occurs, this exception code will be returned. There are other exception codes defined in Modbus™ but these are the only ones used by the CXT. NOTE: When using Detcon controllers, Modbus exceptions should be turned off.
Model CXT-IR and the other for the CXT transceiver. For a more detailed description of the Register Map please contact Detcon.
Model CXT-IR Offset 8199 8200 8201 8202 8203 8204 8205 8206 8207 8208 8209 8210 4.2.
Model CXT-IR 4.2.2 CXT Transceiver Registers 4.2.2.1 Battery Info – Multiple Registers If a Detcon smart battery pack is connected to the CXT, there are five registers associated with information about that battery. The CXT utilizes the I2C interface to read battery status and only one Detcon battery pack can be read per CXT. The controller can determine if a battery is present by reading the Status Register (register 8204).
Model CXT-IR write (function code 06) to register 8202 with the number of seconds the network should go into low power mode. During low power mode, there can be no access to any device on the network so changes in sensor readings will not be updated. Once a non-zero value is written to this register on all transceivers, they will begin counting down until the Update Rate register reaches zero, at which time all transceivers should be active again and ready for network communication.
Model CXT-IR 5. Service and Maintenance Calibration Frequency In most applications, monthly to quarterly span calibration intervals will assure reliable detection. Upon initial installation and commissioning, close frequency tests should be performed, weekly to monthly. Test results should be recorded and reviewed to determine a suitable calibration interval due to differences in industrial environments.
Model CXT-IR 1. Remove the cover from the J-box 2. Press Tri-C Battery Holder down slightly to disengage latch and rotate counter-clockwise according to instructions on lid to remove from Enclosure Base. Lift Battery Holder from Enclosure Base. 3. Unscrew the cover screws on the battery holder. The screws are captive screws, removal of the screws is not necessary. 4. The orientation of batteries is marked on the inside of the cover and the holder. Remove the batteries from the battery holder. 5.
Model CXT-IR 5.2 Replacement of Plug-in Sensor NOTE It is not necessary to remove power while changing the plug-in combustible gas sensor in order to maintain area classification, since it is intrinsically safe. NOTE Only replace the plug-in sensor with an authorized CXT-IR family of gas sensors. Locking Setscrew Display Window detcon inc. ITM (Bottom View) MODEL CXT-IR Locking Setscrew Plug in Sensor (Bottom view) Figure 19 Sensor Cell and ITM Mating 1.
Model CXT-IR 5. Use a 1/ 8 " Allen wrench to release the locking cap head screw that locks the ITM and splashguard adapter assembly together (One turn only - Do not remove setscrew completely). 6. Unthread and remove the splashguard adapter assembly and splashguard from the ITM. These will be re-used with the new ITM. 7. Gently remove the plug-in combustible gas sensor from the old ITM and install it in the new ITM.
Model CXT-IR 6. Troubleshooting Guide If the ITM detects any functional errors the ITM will display the fault. If the sensor is experiencing a fault condition a momentary swipe of the magnet will cause the ITM to scroll the fault condition(s) across the display before the ◄ or ► prompt will appear.
Model CXT-IR Clearing problem Probable Causes: Failed sensor, cal gas not removed at appropriate time, problems with cal gas and delivery, background of target gas. • The sensor must recover to < 10% of range in < 5 min after Span calibration is complete • Use bottled air (zero air or N 2 ) if there is a known continuous background level. • Check validity of span gas using pull tube or other means (check MFG date on cal gas cylinder).
Model CXT-IR 7. Customer Support and Service Policy Detcon Headquarters Shipping Address: 4055 Technology Forest Blvd, Suite 100, The Woodlands Texas 77381 Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067 Phone: 888.367.4286, or 281.367.4100 Fax: 281.292.2860 • www.detcon.com • service@detcon.com • sales@detcon.com All Technical Service and Repair activities should be handled by the Detcon Service Department by phone, fax or email through the contact information given above.
Model CXT-IR 8. CXT-IR Sensor Warranty Detcon, Inc., as the manufacturer, warrants under intended normal use each new CXT-IR sensor to be free from defects in material and workmanship for a period of one year from the date of shipment to the original purchaser. Should the sensor fail to perform in accordance with published specifications within the warranty period, return to Detcon, Inc., for necessary repair or replacement.
Model CXT-IR 9. Appendix 9.1 Specifications 9.1.1 System Specifications Sensor Type: Continuous diffusion/adsorption type NDIR Non-Disperse Infrared Sub-miniature plug-in replaceable type Sensor Life: 5 years typical Measuring Ranges: 0-100% LEL, 0-100% by volume Accuracy/ Repeatability: ± 3% LEL in 0-50% LEL range, ± 5% LEL in 51-100% LEL range Response Time: T50 < 10 seconds, T90 < 30 seconds Warranty: 1 year 9.1.
Model CXT-IR 9.
Model CXT-IR 9.3 Revision Log Table 5 Revision Log Revision Date Changes Approval 1.0 1.1 5/18/12 12/04/12 LBU BM 1.2 1.3 1.4 1.
Model CXT-IR This page left intentionally blank Shipping Address: 4055 Technology Forest, Suite 100, The Woodlands, Texas 77381 Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067 Phone: 888.367.4286, 281.367.4100 • Fax: 281.292.2860 •www.detcon.com • CXT-IR Instruction Manual Rev. 1.
