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PT395 Series LEL Sensor      Rev 6 
 

12 

Installation 

 

Refer to figure 5 for model PT395 explosion proof enclosure for mounting and 
conduit connection. 

 

 
  

 
Figure  5.     Explosion proof sensor enclosure. 
 
 
 
Follow steps below for installation. 
 

1. 

 

Remove the enclosure cover and un-plug the transmitter board by simply 
moving the thumb screws in counter-clockwise direction until they have loosen 
up. Slowly pull the transmitter board and detach the ribbon cable.  

Do not 

completely un-screw or remove the thumb screws from the transmitter board. 

 

 

2. 

 

Mount the enclosure.  Refer to the figure above for mounting hole dimensions. 
Avoid mounting the sensor to fixtures with heavy vibrations. 

 

3. 

 

Using a 3 conductor cable connect the termination board with the monitor or 
controller as shown in figure 3.  For the cable size a reference table is provided 
below. 

 

Содержание PT395 Series

Страница 1: ...Model PT395 Stand Alone Sensor For Combustible Hydrocarbons Revision 6 Operator s Manual Pem Tech Inc Houston Texas U S A ...

Страница 2: ...16 Gas Reading Display 16 Signal Output 4 20mA 16 Alarm Conditions 17 Low High Alarm Fault 17 Resetting Alarms 18 Calibration 19 Sensor calibration 19 Recommended Calibration Gases 21 Calibration errors and remedies 22 Calibration Flow Chart 23 Description General Information 24 Selective response to different Combustible Gases Adjust alarm set points 26 Setting Low High Alarm Levels 26 MAINTENANC...

Страница 3: ...ts beyond the control of PEM TECH including but not limited to damage by accident negligence tampering or failure to operate in accordance with the procedures outlined in the Operations Manual PEM TECH s liability under no circumstances will exceed replacement of the unit claimed to be defective The warranties specified herein are in lieu of any and all other warranties express or implied In no ev...

Страница 4: ...of the problem and obtain shipping address Properly pack the equipment before shipping Also include your complete shipping address and contact name and phone number For non warranty repairs you must provide the limit to repair costs State if a quote for repair cost is required before you can authorize the repair cost For this an additional charge may be applicable NOTE 1 For all the repairs under ...

Страница 5: ...trusive sensor calibration procedure has to be performed then de classify the area before opening the sensor junction box The sintered flame arrestor on the stainless steel sensor head is an integral part of the complete sensor assembly Do not operate the gas sensor with the flame arrestor removed or damaged CAUTION If needed the sensor threads should be coated with silicone free grease The juncti...

Страница 6: ...onds CSA Performance Test CLASSIFICATION CSA Class I Div 1 Groups B C D C22 2 No 152 CE0081 II 2 G Ex d IIC T6 Suitable for use in hazardous locations POWER INPUT 14 30 VDC 24VDC Nominal POWER CONSUMPTION 4 Watts ANALOG OUTPUT 4 20mA DC linear Maximum of 300 Ohms loop resistance DISPLAY 3 Digit LED display ALARM RELAYS Low High Malfunction Relay contacts Normally open or Normally closed Form C typ...

Страница 7: ...ays are fully programmable as Low and High alarms and 1 for sensor Fault or Malfunction The sensor also features a non intrusive calibration Calibration is performed by activating an internal magnetic switch All calibration and alarm configuration data is maintained in a non volatile memory Sensor transmitter board and connection board are enclosed in an explosion proof junction box rated Class I ...

Страница 8: ...d to the connection board via ribbon cable and secured onto the stand off via two thumb screws To remove the transmitter board simply move the thumb screws counter clockwise and slowly pull the transmitter board away Unplug the ribbon cable to completely remove the transmitter board from sensor unit Note Do not use force to tighten the thumb screws when installing the transmitter board back on the...

Страница 9: ...and 4 20ma output Three 3 Pin terminal blocks are also used for alarm connections Each pin on alarm terminal block is as C common NC normally closed and NO normally open See Figure 3 The 3 pin terminal at the bottom of the board is labeled SENSOR Three 3 wires from the sensor head assembly are connected to this terminal These wires are connected as follows R Red wire Sensor Positive 2 VDC Supply B...

Страница 10: ...PT395 Series LEL Sensor Rev 6 10 Wiring Diagram DC Power and 4 20mA signal output Figure 3 Connection to DC Power Supply and PLC input module ...

Страница 11: ...PT395 Series LEL Sensor Rev 6 11 Wiring Diagram Low and High Alarms Figure 4 Connection to Alarm warning devices ...

Страница 12: ...b screws in counter clockwise direction until they have loosen up Slowly pull the transmitter board and detach the ribbon cable Do not completely un screw or remove the thumb screws from the transmitter board 2 Mount the enclosure Refer to the figure above for mounting hole dimensions Avoid mounting the sensor to fixtures with heavy vibrations 3 Using a 3 conductor cable connect the termination bo...

Страница 13: ...ansmitter board on two 2 stand offs using thumb screws on the board Note Do not apply excessive force to tighten the screws 5 Place the cover back on the enclosure Reference Wire size Table Wire Size Max Distance Wire length 14 AWG 3300 Feet 18 AWG 1400 Feet 16 AWG 2200 Feet 20 AWG 900 Feet Note The table above is for reference only ...

Страница 14: ...he sensor will return to its normal operation If different alarm set points are desired then refer to section Adjust Alarm Set Points to modify alarm parameters If the sensor does not start with the sequence as stated above or 00 is not displayed check to see if the ribbon cable connector is properly inserted If necessary unplug the ribbon cable and plug it back again The connector is keyed and ca...

Страница 15: ...0mA The 4 20mA signal output is directly proportional to the detection range of the sensor The output signal generated is proportional to the gas concentration displayed on the LED display of the unit Use the formula below to compute the mA output for any given gas concentration or vice versa Formula to convert gas reading to mA 16 x gas_reading 4 Analog output mA Detection Range Formula to conver...

Страница 16: ...l light up and low alarm relay is energized High Alarm The sensor is said to be in high alarm condition if the gas concentration reaches the high alarm set point The high alarm red LED indicator lights up and the high alarm relay is energized Fault Sensor Fail PT395 is in Fault Malfunction condition when the sensor assembly malfunctions In Fault condition the 4 20mA output generated would be less ...

Страница 17: ...hing option is selected then the alarm must be manually reset To do this place the magnetic tool against the cover The magnetic sensor is located at the 4 o clock position Continue to hold the magnet to the cover and the sensor will display rSt short for RESET on the LED display for few seconds Figure 6 Magnetic Sensor Position 4 o clock to RESET alarms and to adjust alarm levels set points ...

Страница 18: ...tivate the internal switch to initiate the calibration Once the calibration is initiated the alarm relay will be deactivated and the 4 20mA analog signal will be held at approximately 2mA to avoid any false alarm Follow the steps below to calibrate the sensor 1 Make sure there are no combustible vapors present in ambient air 2 Remove the rain splash guard if attached 3 Place the magnetic tool agai...

Страница 19: ... data into memory When completed the display will starts flashing rapidly At this time remove the calibration gas and allow the sensor to clear Do not remove the calibration gas while Adj is being displayed Remove the gas only when the adjustment is completed and the display is rapidly flashing with calibration gas value 9 The sensor calibration has been successfully completed 10 While the gas fro...

Страница 20: ...PT395 Series LEL Sensor Rev 6 20 Figure 8 Sensor Calibration using flow regulator and calibration adapter ...

Страница 21: ...uld be between 0 9 and 1 1 volts Error code 3 Calibration Time Out After initial adjustment the unit waits maximum of 60 seconds for the calibration gas Calibration is aborted if no calibration gas is detected by the microprocessor Check for the leaks in the calibration apparatus and check the flow rate Always use a calibration adapter and proper flow rate A completely dead sensor could also resul...

Страница 22: ...alibration gas value at the slower rate when the gas is detected by the unit Apply Calib Gas for 1 minute Display flashing once every second 1 minute calibration time ended AdJ is displayed for few seconds Sensor making final adjustments and recording calibration data Do not remove the gas while ADJ is being displayed Remove Calib Gas when display Starts flashing rapidly approximately 5 times per ...

Страница 23: ...m level Typical low and high alarm levels for LEL are 20 and 40 respectively General Information Every combustible gas has a minimum and maximum concentration in air which form the flammable or explosive range The lower explosive limit LEL is defined as the smallest amount of gas that could ignite when mixed with air or oxygen The table below shows the max LEL limit of various gases Combustible Ga...

Страница 24: ...Methane Gas Response Relative to Methane Acetic Acid 0 20 Nonane 0 25 Acetone 0 6 n Pentane 0 55 Ammonia 0 55 n Propanol 0 55 Benzene 0 40 n Propyl Alcohol 0 55 Butyl Acetate 0 40 Propane 0 70 Cyclo hexane 0 50 Propylene 0 75 Cycle pentane 0 55 Styrene Monomer 0 30 Decane 0 20 Toluene 0 30 Dioxane 0 55 Xylene 0 40 Ethane 0 80 Ethanol 0 75 Ethyl Acetate 0 55 Ethylene 0 70 Hydrogen 1 00 Iso Butane 0...

Страница 25: ...the concentration of oxygen in ambient air falls below 10 Catalytic bead sensors are designed to operate in the range of 0 100 LEL Sensor exposure to extreme high concentration of hydrocarbons may destabilize the sensor detector element and could effect the sensitivity In such events the sensor must be allowed to clear for at least one 1 hour and then re calibrated to ensure proper operation ...

Страница 26: ...e cover of the junction box until the yellow alarm LED indicator starts flashing and the low alarm level is displayed 2 To change the current alarm level continue to hold the magnet The alarm level is incremented by 1 Move the magnet away once the desired alarm level is displayed The alarm set point resets to 00 after the full scale range of the sensor 3 Wait for 10 seconds The unit will display l...

Страница 27: ...activated when the gas concentration falls below the pre set alarm level Latching Relay will stay active even after the gas concentration falls below the preset alarm level The alarm relay must be manually reset using the internal magnetic switch To RESET alarms refer to section Resetting Alarms Factory defaults alarm relay settings are Non Latching ...

Страница 28: ...re proper operation Protect flame arrestor from paint or high pressure water hose If necessary install some protective shield on the unit before painting or cleaning Be sure to remove the protective shield when finished Routine Maintenance Model PT395 Sensors do not require routine maintenance However the sensors should be inspected periodically to ensure proper operation Sensor Inspection Keep th...

Страница 29: ...the transmitter board assembly 4 The sensor head assembly is connected via 3 wires on the bottom terminal labeled SENSOR Disconnect the wires 5 Unscrew the stainless steel sensor head to remove from the junction box 6 Install the new sensor head Lubricant can be used to coat the threads of the sensor head Do not use the silicone based lubricant 7 Connect the sensor head wires to the terminals as s...

Страница 30: ...1 Termination Connection Board Assembly S 121 LEL Sensor Head assembly stainless steel C 301 Rain guard C 800 Magnet Tool for Calibration and alarm adjustment C 251 Calibration Adapter with tubing 14 105 Disposable calibration gas bottle 103 Liters 50 LEL 2 5 Methane in air 14 165 1 5 Liters per minute LPM flow regulator ...

Страница 31: ...II 2 G Ex d IIC T6 Proof of Compliance For which an EC Type Certificate LCIE 07 ATEX 6050 X 01 according to ANNEX IV has been obtained Application of Directive ATEX Directive 94 9 EC Applicable Standards Compliance with the Essential Health and Safety Requirements has been assured by compliance with EN 60079 0 2006 EN 60079 1 2007 and EN 13980 2002 Final Declaration I the undersigned hereby declar...

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