Dwyer PMT - Manual (Page 29)

Particulate Monitoring Systems
Installation & Operating Manual
Document No. 210-1015-F Page 23 ©2007
10. Troubleshooting
The most important aspects of troubleshooting are to keep in mind the instrument is monitoring small
signals. The quality of cable connectors should not be overlooked. The sensor housing should be kept
dry and clean. Break all troubleshooting down into the basic system components, the sensor, smart
transmitter module and 4-20mA loop.
False High Signals (False Alarms)
1. When an apparent false high signal is present, first check the process to be sure the particulate
level has not increased. Keep in mind that the system can detect very low levels. In filtration
applications the system can detect invisible particulate levels and very small emissions.
2. Check the sensor cover and conduit seal to be sure they were not left open allowing rain to enter
the housing. Check the coaxial cable (two piece configuration only) connectors using a digital
voltmeter and check for shorts. If nothing can be found, conduct a system zero check.
No Reading or Alarm (When Believed Necessary)
1. Increase the particulate level or introduce particulate into the air stream and monitor for a response.
If the system responds properly re-evaluate the selected alarm points and the process conditions.
2. If there is no response, check for electrical continuity from the sensor to the control unit end of the
coax cable (two piece configuration only).
3. Contact the factory for a Field Test Unit that can generate a signal to check response and
calibration (two-piece configuration only).