PART FOUR - SERVICE AND MAINTENANCE
SECTION 3 - TROUBLESHOOTING
Rev. 0-201
PRO-series Model C3 Conductivity Transmitter
65
Finding Source
of Ground Loop
☞
3.2 Isolating Measuring
System Problem
Checking
Electrical Connections
Verifying
Sensor Operation
Verifying
Transmitter Operation
Sometimes the source of a ground loop is easy to find, but it
usually takes an organized approach to isolate the problem.
Troubleshooting Tip!
Use a systematic troubleshooting
method. If possible, start by grounding all shields and
electrical grounds at one stable point. One at a time, turn
off all pumps, motors, and switches that are in contact
with the process. Each time you do this, check if the
ground loop still exists. Since the process media being
measured is electrically conductive, the source of the
ground loop may not be readily apparent.
When experiencing problems, try to determine the primary
measurement system component causing the problem (sen-
sor, transmitter or interconnect cable, if used).
1. Verify that adequate DC voltage exists at the appropri-
ate transmitter TB1 terminals.
2. Check all transmitter wiring to ensure proper connec-
tions.
To verify sensor operation, refer to the procedure in the
troubleshooting section of the sensor operating manual.
1.
After disconnecting DC power and the sensor from the
transmitter, connect a 1% tolerance, 1097 ohm resistor
between Terminals 4 (white) and 5 (blue) on TB2.
(When configured for a PT100 temperature element,
use a 1% tolerance, 110 ohm resistor.)
2.
Depending on the configured sensor cell constant,
measuring units, and range, use the listed resistance in
Table D (1% tolerance resistor or decade box) and
connect it between Terminals 1 (red) and 7 (black) on
TB2.
