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Crowcon TXgard-IS Plus Installation, Operating And Maintenance Instructions

Intrinsically safe toxic and oxygen gas detectors
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TXgard
MANUAL
 
 
 
JUNHO 2013
 

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Summary of Contents for Crowcon TXgard-IS Plus

  • Page 1       TXgard MANUAL           JUNHO 2013...
  • Page 2 TXgard-IS+ Intrinsically Safe Toxic and Oxygen Gas Detectors Loop Powered Electrochemical and Galvanic Sensor Types Only Installation, operating and maintenance instructions, M07214 Issue 7 January 2010...
  • Page 3 Routine maintenance ................24 Sensor replacement and servicing of detectors ........24 Fault finding ................26 Appendices Appendix A Wiring the TXgard-IS+ to Crowcon control equipment .... 31 Appendix B TXgard-IS+ specification............35 Appendix C Spare parts ................37 Appendix D Menu system................

  • Page 4: Introduction

    Gases include oxygen, carbon monoxide and hydrogen sulphide. For a full list of supported sensors, please contact Crowcon. TXgard-IS+ is a loop-powered instrument providing a 4-20 mA signal suitable for direct connection to a control panel. Unlike most other 4-20 mA...
  • Page 5 TXgard-IS+ Introduction entry for customer use as standard. Side entry versions and gland adapters are available (contact Crowcon for details). The Personality Module , mounted on the baseboard, comes in two varieties: Toxic and Oxygen. It converts the sensor output into a standard signal which can be interpreted by the processor.
  • Page 6 The warranty period for the sensor begins from the date of shipment from Crowcon. Detectors should be stored in a cool and dry environment where temperatures remain within the 0-20°C range...

  • Page 7: Installation

    The agreement reached on the locations of sensors should be recorded. Crowcon is pleased to assist in the selection and siting of gas detectors. Issue 7...

  • Page 8: Mounting

    Cabling to TXgard-IS+ must be in accordance with the recognised standards of the appropriate authority in the country concerned, and must also meet the electrical requirements of the detector. Crowcon recommends the use of 2-core twisted pair cable, but there is no particular restriction as long as it can supply 8 V at 20 mA to the instrument terminals.

  • Page 9: Electrical Connections

    “Figure 2.2” below, shows the baseboard in detail. The terminals marked J4 should be connected to the control equipment using the appropriate and – terminals. For further details of wiring the TXgard-IS+ to Crowcon equipment see "Appendix A". Figure 2.2: Baseboard...
  • Page 10 Installation TXgard-IS+ TXgard-IS+ is a 4-20 mA sink, loop-powered device designed to work in safe and hazardous zones 0, 1 and 2 areas when used in conjunction with an appropriate barrier. Figures 2.3, 2.4 and 2.5 summarise the electrical connections. SAFE AREA Figure 2.3: Electrical connections for safe area HAZARDOUS AREA...
  • Page 11 TXgard-IS+ Installation Figure 2.5: Electrical connections using galvanic isolator Issue 7...

  • Page 12: Operation

    Operation TXgard-IS+ OPERATION 3.1 The operator display panel and keypad The TXgard-IS+ provides an operator display panel through a Liquid Crystal Display (See “Figure 3.1”). The operator display panel allows you to communicate with the TXgard-IS+ instrument through a series of text based menus.

  • Page 13: Using The Txgard-Is+ Menus

    TXgard-IS+ Operation Figure 3.3: Power and temperature display (after pressing DOWN key) Power V Power: 21.5V Temp: 25.0 C TXgard-IS+ Temperature 3.2 Using the TXgard-IS+ menus Three buttons are provided to select the menu options and respond to instrument messages, the  (UP) and  (DOWN) button moves your selection through the menu list, a cursor ‘...
  • Page 14 TXgard-IS+ Operation Issue 7...

  • Page 15: Commissioning

    TXgard-IS+ Commissioning COMMISSIONING The commissioning procedures for toxic detectors can be found in section 4.1. To commission oxygen detectors go to section 4.2. Warning Before carrying out any work, ensure that local regulations and site procedures are followed. Ensure that the associated control panel is inhibited to prevent false alarms.
  • Page 16 Commissioning TXgard-IS+ current, then it can be checked as outlined below. Alternatively the TXgard-IS+ provides a facility to force a known current through the loop. Refer to the Ramp mA menu item in Appendix D for instructions. NOTE: there is no need to disconnect a sensor when calibrating mA! The mA control circuit is completely independent from the gas measuring circuit! 1 Connect a digital voltmeter (DVM) across test points TP1...
  • Page 17 TXgard-IS+ Commissioning 6 Press the  button to start zeroing the detector. The instrument will display the following message: Zeroing Sensor.. TXgard-IS+ When complete the instrument will report a scrolling text message ‘Zero operation successful’. 7 Press the  button to continue, the display will return to the Zero/cal submenu.
  • Page 18 The panel will display a scrolling text message: ‘Apply calibration gas to instrument ––’. 6 Apply calibration gas (typically half or full scale) to the detector at a flow rate of 0.5 litre/minute. (Crowcon Flow Adaptor part No. C03005) Sticky gases which are rapidly absorbed by connecting pipes (chlorine, nitrogen dioxide and ozone) are applied at 1 litre / minute.
  • Page 19 See "Table 4.1" on page 21 for some gases and their typical range. Please note that detectors can be provided in different ranges if required. Contact Crowcon for list of all gases detected. 8 Select the  button to set the calibration value. The instrument will display the following message: Calibrating..

  • Page 20: Commissioning Procedure Oxygen Detector

    Commissioning TXgard-IS+ Table 4.1: Typical gas ranges Gas Code Unit † Standard Ranges Oxygen %vol 0-25 Carbon monoxide 0-250 Hydrogen sulphide 0-25 Sulphur dioxide 0-10 and 0-100 Chlorine † Note: other ranges are available on request 4.2 Commissioning procedure: Oxygen detector Step 1: Connecting the detector to the control panel 1 Apply power to the detector via 2-way connector J4.
  • Page 21 TXgard-IS+ Commissioning NOTE: there is no need to disconnect a sensor when calibrating mA! The mA control circuit is completely independent from the gas measuring circuit! 1 Connect a digital voltmeter (DVM) across test points TP1 and TP2 on the baseboard (“Figure 1.1” on page 6 or “Figure 2.2”...
  • Page 22 Commissioning TXgard-IS+ 6 Press the  button to start calibrating the detector. The instrument will display the following message: Calibrating.. TXgard-IS+ When complete the instrument will report a scrolling text message: ‘Calibration successful’ 7 Press the  button to continue and exit the menu system. The instrument is now calibrated.

  • Page 23: Maintenance

    2-3 years, and 2 years for the oxygen sensors. Site practices will dictate the frequency with which detectors are tested. Crowcon recommends that detectors be gas tested every month and recalibrated every six months. To recalibrate a detector, follow the steps in Section 4.1 (for a toxic gas detector) or Section 4.2 (for an oxygen...
  • Page 24 Maintenance TXgard-IS+ 1. Open the sensor housing by pushing in and turning simultaneously to release the bayonet fitting and expose the sensor. 2. Remove the sensor from the sensor housing. 3. Fit the replacement sensor, checking the part number is correct. This part number is labelled on the main body of the detector.

  • Page 25: Fault Finding

    Fault finding TXgard-IS+ Issue 7...
  • Page 26 TXgard-IS+ Fault finding Issue 7...
  • Page 27 Fault finding TXgard-IS+ Issue 7...
  • Page 28 TXgard-IS+ Fault finding Issue 7...
  • Page 29 Fault finding TXgard-IS+ Issue 7...

  • Page 30: Appendix A Wiring The Txgard-Is+ To Crowcon Control Equipment

    CONTROL EQUIPMENT This appendix describes how to connect the TXgard-IS+ to the following Crowcon control panels: Vortex, Gasmonitor, Gasmaster and Gasflag. The instructions for connecting the cards and setting the links are outlined below. Connection details for the Ditech range of control equipment will be included on the wiring diagrams supplied for the system.
  • Page 31 Quad Channel Module, see “Figure A.1”. Connecting the TXgard-IS+ to a Crowcon Gasmonitor The TXgard-IS+ is connected to the Gasmonitor control panel via an INPUT/OUTPUT MODULE at the rear of the Gasmonitor racking system.
  • Page 32 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Channel Connecting the TXgard-IS+ to a Crowcon Gasmaster The TXgard-IS+ is connected to a Gasmaster control panel as shown below. The Gasmaster input channel link should be set to 'SINK' and the input channel should be configured as 'DET 4-20 SINK'.
  • Page 33 Appendix A TXgard-IS+ Connecting the TXgard-IS+ to a Crowcon Gasflag The TXgard-IS+ is connected to the Gasflag via the screw terminals marked SENSOR +VE (this is the TXgard-IS+ positive supply) and SENSOR SIG (which connects to TXgard-IS+ negative supply). Set links LK10A and LK10B to SOURCE, position B.

  • Page 34: Appendix B Txgard-Is+ Specification

    –40°C and +65°C, giving out a 4-20 mA signal proportional to measured gas; but LCD will go blank at about –20°C. The sensor's performance changes at extremes of temperature; consult Crowcon if the detector will be exposed to ambient temperatures below -20°C or above +40°C Humidity...
  • Page 35 Appendix B TXgard-IS+ Standards EN60079-0 (safety in flammable atmospheres) EN60079-11 (intrinsic safety) EN50022 (emissions) IEC61000-4 (immunity) EN50270 (EMC for gas detection equipment) EN50271(software design standard) UL (UL913 Ed 7) cUL (CSAC22.2 No.157) class 1 group A,B,C and D This device complies with part 15 of the FCC Rules.

  • Page 36: Spare Parts

    TXgard-IS+ Appendix C APPENDIX C SPARE PARTS AND ACCESSORIES Please contact Crowcon for details of the latest replacement sensors. Please quote the part number given on the "Sensor Replacement label" mounted on the outside of the sensor housing. Description Part Number M20 to ½"...

  • Page 37: Appendix D Menu System

    Appendix D TXgard-IS+ APPENDIX D MENU SYSTEM This section provides greater details for the TXgard-IS+ menu items and is a supplement to the section “Using the TXgard-IS+ menus” on page 14. You may wish to refer to the Menu Map on the back cover to familiarise yourself with the menu hierarchy.
  • Page 38 TXgard-IS+ Appendix D The display should look as follows; Inhibit active Press to go on TXgard-IS+ Gas Calibration Menus Description: The gas calibration menus provide the instructions and means to calibrate the instrument. This menu is different for toxic detectors and oxygen detectors.
  • Page 39 Appendix D TXgard-IS+ Ramp mA output Description: This menu item allows you to force the output loop current to a known value. It does not calibrate the 4-20 mA loop current or affect any calibration values within the TXgard-IS+ detector. The TXgard-IS+ provides convenient test points within the instrument to measure the loop current.
  • Page 40 TXgard-IS+ Appendix D cable. The voltage must remain greater than 8 V at the instrument terminals for the instrument to function. 3. Use the UP  and DOWN  keys to adjust the loop current value. The current value will increment in 0.5 mA steps. The default value of the loop current when the menu is first entered is 4 mA.
  • Page 41 Appendix D TXgard-IS+ Menu item Options Description To Main Menu Exit Exit to main menu. Limit 4-20 mA Enable / Disable If enabled, the instrument will only ever draw a maximum of 20 mA, no matter what the gas value. Set inhibit mA Minimum, 3 mA, When the instrument is in inhibit...
  • Page 42 TXgard-IS+ Appendix D Menu item Options Description Fatal mA Minimum, 3 mA, This selects the current the 24 mA or Gas instrument will sink when a fatal Level error has been detected. Note: the option ‘gas level’ is available; this means the instrument will ignore the error for the purposes of loop current - a display message will still flash as normal.
  • Page 43 Appendix D TXgard-IS+ Calibrate mA Description: The Calibrate mA menu provides a means of re-calibrating the 4-20 mA loop current. NOTE: The TXgard-IS+ detectors leave the factory with the 4-20 mA signal correctly calibrated. This menu is provided for Service Engineers to adjust the calibration to match site control equipment which cannot itself be correctly calibrated.
  • Page 44 TXgard-IS+ Appendix D 5. To calibrate the 20 mA, select the Calibrate 20mA menu item and repeat step 4 adjusting the voltage reading to 20 mA value (nominally 200 mV). Press the  key when finished. 6. Exit the menu system. Clear Faults Description: Clears Faults from display and unit.

  • Page 45: Appendix E 4-20 Ma Loops

    Appendix E TXgard-IS+ APPENDIX E 4-20 mA LOOPS A 4-20 mA loop is a standard method of connecting remote instruments to a control panel. The basic concept is that a reading of zero gas corresponds to 4 mA, and full scale gas corresponds to 20 mA. The control panel supplies typically 24 volts down 2 wires, and measures the current flowing in the loop.
  • Page 46 TXgard-IS+ Appendix E current signal is measured between the third wire and 0V. Because 3-wire circuits don’t depend on the current in the signal loop to power them, they can also source current. However, they require more expensive Zener barriers to make them intrinsically safe, and cannot be retrofitted into existing 2-wire installations without replacing the cabling.

  • Page 47: Appendix F Cabling Requirement

    Cabling to TXgard-IS+ must be in accordance with the recognised standards of the appropriate authority in the country concerned, and must also meet the electrical requirements of the detector. Crowcon recommends the use of 2-core twisted pair cable, but there is no particular restriction as long as it can supply 8 V at 20 mA to the instrument.
  • Page 48 TXgard-IS+ Appendix F This means that the barrier output will not exceed 28.12 V or 93 mA into the Hazardous Area, due to the barriers' internal clamps and fuse. At these power levels, you can attach up to 0.083 microfarads of capacitance and 3.05 millihenries of inductance and still be safe.
  • Page 49 Appendix F TXgard-IS+ Ω Note 2. It is worth noting that most 28 V Zener barriers are 300 , which will give Ω another 6 V drop. With an 18 V supply and a 250 sense resistor, this would give Ω...

  • Page 50: Appendix G Sensor Limitations

    SENSOR LIMITATIONS The sensors used in TXgard-IS+ have limitations common to all such gas sensors, and users should be aware of the points listed below. Crowcon can advise on particular situations and suggest alternative sensors if the instrument is likely to experience extreme conditions.
  • Page 51 Crowcon reserves the right to determine a reduced warranty period, or decline a warranty period for any sensor supplied for use in an environment or for an application known to carry risk of degradation or damage to the sensor.
  • Page 53 Contactos/Contacts: Comercial/Commercial: Assistência/Service: Fernando Mena Costa Patricia Costa e-mail: fcosta@bhb,pt e-mail: ppcosta@bhb.pt Tel: (+351) 21 843 64 00 Tel: (+351) 21 843 64 00 Fax: (+351) 21 843 64 09...

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