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Air Check

EX

 

LEL Gas Monitor 

Instruction Manual 

PureAire Monitoring Systems, Inc

1140 Ensell Road 

Lake Zurich, Illinois 60047 

Phone: 847-726-6000 

Fax: 847-726-6051 

Toll-Free: 888-788-8050 

www.Pureairemonitoring.com

 

Summary of Contents for Air Check EX

Page 1: ...Check EX LEL Gas Monitor Instruction Manual PureAire Monitoring Systems Inc 1140 Ensell Road Lake Zurich Illinois 60047 Phone 847 726 6000 Fax 847 726 6051 Toll Free 888 788 8050 www Pureairemonitoring com ...

Page 2: ...xperience innovative products and commitment to service will satisfy your specific monitoring needs now and in the future Our growth is a result of our total commitment to supporting our customers We re available 24 hours a day 7 days a week to help you when you need us Our 24 hour Emergency phone number is 1 847 420 3814 We can provide field service preventative maintenance programs and training ...

Page 3: ...485 Serial 11 3 3 3 Alarm Relays 12 4 Normal Operation 13 4 1 Power Up Delay 13 4 1 1 Sensor Poisoning 13 4 2 Concentration Display 13 4 3 Analog Output 13 4 4 Fault Alarm 13 4 5 Concentration Alarms 13 4 6 Alarm Reset 14 4 7 Loss of Power Indication 14 4 8 Routine Maintenance Schedule 15 4 8 1 Routine Visual Checks 15 4 8 2 Recommended Routine Maintenance Schedule 15 5 Maintenance Calibration 16 ...

Page 4: ...85 Serial Interface 20 7 1 1 RTU Address 20 7 1 2 Modbus Data Registers and Function Codes 20 7 1 3 Modbus Configuration Software 22 7 2 Alarm Relays 23 7 2 1 Alarm 3 Sensor Fault Alarm 23 7 2 2 Alarm 1 and Alarm 2 Concentration Alarms 23 7 2 3 Alarm Relay Configuration 24 ...

Page 5: ... explosion proof enclosure The enclosure is suitable for use in Class 1 Group B C D and Class 2 Group E F and G hazardous areas NOTE Acetylene monitor enclosure is special and rated for Group A The system has the following features Explosion proof transmitter enclosure Non intrusive one man calibration Local digital display 4 20 mA output Supervised sensor cell 24 VDC operation A variety of output...

Page 6: ...activated It also flashes once per second without a magnet near the keypad to signal a Fault condition Cal Key A magnetic key used to place the instrument in the Calibration mode Span Adjustment Keys Magnetic keys used to adjust the instrument s span gain up down when in the Calibration mode Display current gain setting when touched with a magnet during normal operation Zero Adjustment Keys Magnet...

Page 7: ...sifying area Front Panel Incorporates local digital display magnetic keys etc See 1 1 1 above for front panel component details Sensor Sensor Cover Renewable plug in electrochemical sensor with threaded cover 1 1 3 Gas Sensor LEL Sensor This is a disposable cell that has an operational life of approximately 4 to 5 years IMPORTANT Be sure to classify the area as non hazardous prior to Opening the S...

Page 8: ...roprietary catalytic bead Sensor Life 4 to 5 years under normal conditions Detectable Gases Combustible Gases Acetylene Methane CH4 Gasoline Hexane Propane Hydrogen IPA 2 3 Signal Outputs Local Display 3 1 2 digit LCD Analog Output 4 20 mA isolated 4 20 mA output optional Serial Output Optional Modbus RS 485 serial interface Alarm Relays Optional SPDT High Warning and Fault alarm relays 2 4 Electr...

Page 9: ...eAire Monitoring Systems Inc 10 25 07 8 2 6 Safety Characteristics Transmitter enclosure suitable for Class 1 Group B C D and Class 2 Group E F and G hazardous areas Also meets NEMA 4 with included O ring ...

Page 10: ...utput signal wire which is typically 4 20 mA The third wire is system common and serves as power supply and signal returns These connect to the three point terminal block labels TB2 An earth ground lug inside the enclosure is provided for earth grounding of shied wires PureAire recommends the use of a General Cable E2203S 30 86 or equivalent for analog output and 24 VDC power input The maximum per...

Page 11: ...ated 4 20 mA Modbus serial output SPDT alarm relays Optional outputs are provided using an auxiliary factory installed electronics board The instrument can only accommodate one optional output 3 3 1 Isolated 4 20 mA An optional isolated 4 20 mA output board is available A 2 point terminal strip TB1 provides the 1500 V isolated 4 20 mA output signal TB1 ...

Page 12: ... The gas detector functions as a slave device a PLC or PC running MMI or BUI software equipped with a Modbus driver functions as the master The RS 485 standard allows cable lengths up to 4000 feet between the Modbus master and slave Both 4 wire full duplex and 2 wire half duplex connections are supported by the Modbus RS 485 serial interface option NOTE See Appendix for RTU address Registers and F...

Page 13: ... RFI that may interfere with measurement signals The alarm relay PCB also incorporates a remote reset switch TB4 for use if the alarm relays are configured for latching operation see Appendix These alarms are factory set as follows Alarm 1 20 LEL non latching Alarm 2 40 LEL latching Alarm 3 This is a fail safe Fault relay and is activated when a sensor fault such as a missing sensor is detected It...

Page 14: ...djacent to the digital display When the instrument is in the normal monitoring mode the left arrow indicator on the LCD will be off Should the measured concentration exceed the range of the instrument however the left arrow indicator will flash rapidly and three horizontal dashes will appear on the LCD 4 3 Analog Output During normal operation outputs an analog signal directly proportional to the ...

Page 15: ...m signal or locally by holding the magnet at about the 7 o clock position on the base of the cover assembly 4 7 Loss of Power Indication In the event the Air Check EX loses VDC power the local display go blank and the 4 20 mA analog output signal will drop to 0 If the instrument is configured with the optional Fault Alarm Relay that relay will de energize On units equipped with the Alarm Relays op...

Page 16: ...ntended to serve as general guidelines for routine maintenance The conditions in your particular application as well as your organization s maintenance policies will ultimately determine the best routine maintenance schedule for your equipment 4 8 1 Routine Visual Checks Item Status With No Gas Present Local Display Display should read 0 0 0 for LEL gases Fault Keypad LED Should not be illuminated...

Page 17: ... Air Check EX features a magnetic keypad which permits one man non intrusive calibration All zero and span adjustments can be made without removing the cover of the enclosure housing To place the instrument in the Calibration mode briefly hold the magnet over the CAL key located on the lower left of the front panel The left indicator arrow on the upper left side of the LCD will light and the 4 20 ...

Page 18: ...sor cell will continuously rise therefore only expose the cell to a flow rate of 200cc min for 1 2 minutes and then adjust the span to the calibration standard If the cell is exposed to higher flow rates the system will rise too quickly and make it difficult to adjust the span 4 Close the regulator valve on the span gas cylinder and remove from the inlet of the calibration cap Remove calibration c...

Page 19: ...ver time the higher the gain the greater the degree of sensor sensitivity deterioration These values are displayed as follows 1 Exit the Calibration mode and wait for the one minute delay to end the left indicator arrow will stop flashing and remain unlit 2 Hold the magnet over the UP SPAN key The amount of zero offset in percent of full scale will be displayed 3 Hold the magnet over the DOWN SPAN...

Page 20: ...PureAire Monitoring Systems Inc 10 25 07 19 6 Diagrams Schematics 6 1 Dimensional Drawing LEL catalytic sensor cell ...

Page 21: ...e assigned to each Air Check EX The eight DIP switches represent an 8 bit binary number with 1 LSB and 8 MSB EXAMPLE OFF ON ON OFF ON OFF OFF OFF 0110 1000 RTU address 104 A unique RTU address must be assigned to each Air Check EX communicating on the same RS 485 port 7 1 2 Modbus Data Registers and Function Codes The following table identifies the Air Check EX Modbus register locations and the fu...

Page 22: ...g units read as bytes Measurement 40325 40340 3 6 Name 16 ASCII characters assigned to the unit identifier read as bytes Span 40343 3 6 An integer from 1 to 9999 used to scale the A2D ASCII value Alm1Setpoint 40345 3 6 Alm2Setpoint 40347 3 6 Integer compared to the A2D Raw value to determine alarm 1 or 2 status The 0 to 100 set point must be scaled from 197 to 1003 This is done by using Alarm 806 ...

Page 23: ...figured via the serial port This is a one time requirement unless changes within the application necessitate adjustments after the initial installation This functionality may be built into the Modbus master or may be performed with a portable computer running a simple software application Consult PureAire for more information on this software ...

Page 24: ... Fault alarm is not needed this relay can be set to trip with the Alarm 2 relay see 7 2 3 below 7 2 2 Alarm 1 and Alarm 2 Concentration Alarms Alarms 1 and 2 are intended as low and high concentration alarms They are factory set at one and two times LEL respectively Alarm 1 is non latching Alarm 2 is latching Changing the Alarm Setpoint The alarm setpoints for Alarms 1 and 2 are controlled by 16 p...

Page 25: ...tching Alarm 1 Latching 3 Alarm 1 Normal Alarm 1 Fail safe 4 Alarm 2 High Trip Alarm 2 Low Trip 5 Alarm 2 Non Latching Alarm 2 Latching 6 Alarm 2 Normal Alarm 2 Fail safe 7 Alarm 2 No acknowledge Alarm 2 Acknowledge 8 Alarm 3 Fault Alarm 3 Trips with Alarm 2 IMPORTANT PureAire recommends that Alarms 1 and 2 always be set for High Trip activate when measured gas value rises about setpoint except fo...

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