Dwyer DPM - Manual (Page 31)

Particulate Monitoring Systems
Installation & Operating Manual
Document No. 210-1003-M Page 24 ©2007
CONTROL UNIT ZERO CHECK
1. Disconnect power to the control unit.
2. Open the enclosure cover and unscrew the coaxial cable connector from the
control unit. Leave the connector inside the control unit enclosure. Make
sure the connector does not slip down into the conduit.
3. Close the control unit enclosure cover.
4. Re-apply power to the control unit and allow the reading to stabilize for 1-2
minutes.
5. Read the display. It should be below the control units specified minimum
detection level. If the control unit passes this check, there are no false
signals entering the control unit.
PASS:
1. Disconnect power from the control unit.
2. Open the enclosure cover and re-attach the coaxial cable connector to the
control unit.
3. Close the enclosure cover and proceed to the Coaxial Cable Zero Check.
FAIL:
1. If a zero reading cannot be obtained, close the enclosure cover and contact
the factory for further assistance.
COAXIAL CABLE ZERO CHECK
1. Disconnect power to the control unit.
2. Open the sensor enclosure cover and disconnect the coaxial cable center
conductor from the sensor probe end. Do not disconnect the coaxial cable
shield. Do not remove the probe from the process. Leave the coaxial cable
center conductor ring terminal hanging in free space within the sensor
enclosure (do not isolate it with tape) and close the cover.
3. Re-apply power to the control unit and allow the reading to stabilize for 1-2
minutes.
4. Read the display. It should be below the control units specified minimum
detection level. If the coaxial cable passes this check then there are no false
signals entering the coaxial cable.
PASS:
1. Disconnect power to the control unit.
2. Open the sensor enclosure cover and re-attach the coaxial cable center
conductor to the sensor probe end.
3. Close the sensor enclosure cover and proceed to the sensor zero check.
FAIL:
1. Check cable installation and routing instructions in the Installation section
of this manual for proper cable installation. Make any changes necessary.
2. Contact the factory for further assistance.