Troubleshooting – Rice Lake ITCM SS Isolated Tension Cell Module User Manual

Page 10

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4. Junction Box Connections, Adjustments & Calibration

Refer to junction box manual for trimming details.

Refer to indicator manual for system calibration details.

5. Troubleshooting

If the system powers up and gives some type of stable digital readout that varies
with the load on the system, the system problems are probably caused by factors
other than the load cells. Often, load cells are blamed for a malfunctioning system;
90% of the time, the problem lies elsewhere. Look for mechanical causes first.

If the system can be calibrated but doesn’t return to zero, loses calibration, or
demonstrates non-linearity or non-repeatability, see the following chart for pos-
sible causes and refer to the following list of checks.

1.

Check load cell mount for debris restricting load cell movement or debris
between scale and structure.

2.

Check that tank/vessel and mounts are plumb, level, and square at the
critical areas.

3.

Check piping and conduit for connections that restrict vessel movement.

4.

If check rods are used, loosen connections to finger tight only for testing.

5.

Check load cell cables for physical or water damage.

6.

Check all electrical connections, especially in the junction box.

If the problem still is not found:

7.

Check possible indicator malfunction by using a load cell simulator to
input a known good signal into the indicator.

8.

Disconnect each load cell’s signal leads at the junction box and check
individual load cell outputs with a multimeter. Then, check input/output
impedances for comparison with load cell manufacturer’s specifications.

If after all these checks the problem still cannot be isolated, reconnect all but one
load cell. Replace the load cell with a load cell simulator. Alternate so that each load
cell is individually disconnected and replaced with a simulator. If there is a problem
with a particular load cell, the symptom should disappear when that load cell is
disconnected and replaced with the simulator.

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