Tech Note 109 Troubleshooting 500 Series Transmitters

 

OK Light Off:

1. Check +24VDC Power at bottom left terminals
2. Check to be sure Sensor is wired properly to top left terminals.
3. OK Light will turn on after 30 seconds if sensor is OK.
4. If OK Light stays out, check sensor bias or replace sensor
   1. Accelerometer DC Bias should be between 4.0 to 16.0 VDC
   2. Eddy Probe DC Gap should be between -3.0 and -18.0 VDC
5. If sensor is good (DC bias or gap OK) replace transmitter.

No 4-20 mA Output:

1. Check to be sure OK Light is “On” (see above)
2. Disconnect field wires and verify 4-20 mA directly with Digital Volt Meter.
   
3. If OK Light is “On” and there is no 4-20 mA output replace transmitter.

Erratic or Noisy Readings:

1. Check to be sure sensor shield is landed with sensor common.
2. Verify sensor shield is not grounded at each end.
3. Check for ground loops in system.
4. Verify sensor and cabling installation is in conduit and away from AC power.
5. If radios are causing interference, be sure to use metal enclosure and conduit.

 

 

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