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Summary of Contents for Crowcon TXgard-Plus
- Page 1 TXgard-Plus Flameproof Toxic and Oxygen Gas Detector Installation, Operation and Maintenance Instructions M07194 Issue 6 April 2018...
- Page 3 1 Introduction 1.1 Product overview TXgard-Plus is a flameproof toxic and oxygen gas detector suitable for use in zone 1 or 2 hazardous areas. It is designed to detect toxic gases and oxygen using a range of electrochemical sensors. A local display and magnetically operated switches allow non-intrusive one-man calibration without a hot work permit.
- Page 4 Introduction TXgard-Plus 1.3 Status Indication TXgard-Plus includes a local display and status LED, visible through the junction box window, see Diagram 1. The display shows the gas concentration and current mode of operation ie. NORMAL, ZERO or CAL. The LED shows the current alarm state of the detector. This is summarised in Table 1.
- Page 5 TXgard-Plus Introduction Diagram 1: TXgard Plus general arrangement...
- Page 6 Introduction TXgard-Plus Diagram 2: Terminal and amplifier layouts...
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Page 7: Detector Configuration
TXgard-Plus Detector configuration 2. Detector configuration 2.1 Standard configuration As standard, TXgard-Plus is factory set as follows: Current source with 0 mA = Fault 2 mA = Inhibit ie. Zero/Cal mode 4-20 mA = Normal operation 24 mA = Over-range clamp... - Page 8 Detector configuration TXgard-Plus Table 3 details standard alarm points for the available gases and ranges. Range* AL1* AL2* Hydrogen sulphide 0-25 ppm 5 ppm 10 ppm Carbon monoxide 0-250 ppm 30 ppm 200 ppm Oxygen 0-25% vv 19% vv 17% vv *Alternative ranges and alarm set points must be specified when ordering Table 3: Standard ranges and alarm set points.
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Page 9: Installation
3. Installation WARNING TXgard-Plus is designed for use in Zone 1 and 2 hazardous areas and is certified Ex db IIC T6 Gb (AEx d IIC T6 in USA). Installation must be in accordance with the recognised standards of the appropriate authority in the country concerned. - Page 10 Alternative cabling techniques, such as steel conduit, may be acceptable provided appropriate standards are met. TXgard-Plus requires a dc supply of 12-30 V at up to 100 mA. Ensure the minimum dc supply of 12 V is observed at the detector, taking into account the voltage drop due to cable resistance.
- Page 11 TXgard-Plus Installation Resistance (Ohms per km) Max. distance mm 2 (awg) Cable Loop m (ft) 1.0 (17) 18.1 36.2 1000 (3280) 1.5 (15) 12.1 24.2 1500 (4920) Table 4: Maximum cable distances for typical cables Acceptable cross sectional area of cable is 0.5 to 1.5 mm 2 . Table 2 provides guidance only, actual cable parameters for each application should be used to calculate maximum cable distances.
- Page 12 All electrical connections to the optional relays are made via the 6-way terminal block on the terminal board in the base of the junction box (see Diagram 2). The relay contacts are rated 1 A @ 30 Vdc. Diagram 3: Electrical connections to TXgard-Plus...
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Page 13: Operation
Place the end of the ‘CRO-Mag’ over the MENU pad. The decimal point above the word CAL will illuminate. Other indications remain unchanged. i Apply calibration gas to the detector at a flow rate of 0.5 litres/min. (contact Crowcon for the supply of calibration gas.) - Page 14 24 months Site practices will dictate the frequency with which detectors are tested. Crowcon recommend detectors are gas tested at least every 6 months and re-calibrated as necessary following the steps given in 4.1. Detectors fitted with the optional relay module should be periodically tested to verify that any connected alarms or output functions operate correctly when the detector is in alarm state.
- Page 15 Unscrew the complete 96HD sensor housing from the junction box. Note: If a spare 96HD sensor housing complete with new sensor is available ignore steps f to k and return the old 96HD to Crowcon or an approved service centre for repair.
- Page 16 Operation TXgard-Plus Diagram 4: 96HD assembly k Re-assemble the 96HD housing taking time to ensure that the 3 mm Allen head screws are securely fixed into position. I Fit the 96HD sensor housing to the junction box ensuring that the colour coded wires are terminated correctly.
- Page 17 Follow the Commissioning Procedure given in 4.1. 4.4 Changing Alarm Levels (Relay Version Only) WARNING This work should be carried out by Crowcon or an approved service centre unless suitable training has been received. Before attempting to change alarm levels ensure the detector is in fresh air and no flammable gas is present.
- Page 18 Operation TXgard-Plus j Once the alarm level has been set, place end of ‘CRO-Mag’ over the ‘UP’ or ‘DOWN’ arrow pads and reset the display to read zero. k Place the end of the ‘CRO-Mag’ over the ‘MENU’ pad to return the detector to normal operation, ie.
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Page 19: Spare Parts And Accessories
TXgard-Plus Spare parts and accessories 5. Spare parts and accessories Please refer to the Sensor Replacement Label mounted on the outside of the 96HD housing for the correct replacement part number. Description Part number Complete 96HD sensor Sensor housing with sensor... -
Page 20: Specifications
Specifications TXgard-Plus 6. Specifications Dimensions 200 x 115 x 115 mm (8” x 41/2” x 41/2”) Weight 2.2 kg (4.8 lbs) Material 96HD sensor housing: 316 Stainless steel Junction box: Marine grade alloy Temperature range -10°C to +55°C (14°F to 131°F) - Page 22 Fax: +86 10 6787 4879 Website: www.crowcon.com Email: saleschina@crowcon.cn Website: www.crowcon.com Netherlands Office Crowcon Detection Instruments Ltd Vlambloem 129 3068JG, Rotterdam Netherlands Tel: + 31 10 421 1232 Fax: + 31 10 421 0542 Email: eu@crowcon.com Website: www.crowcon.com © 2018 Crowcon Detection Instruments Ltd.
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