Support

Tips for trouble shooting Load Cell and scales

Load cells might be damaged due to many reasons: Overloading, lightning strikes, moisture or chemical ingress, vibrations, corrosion, pulling the cable etc. As a result, the scale may provide unstable readings, zero drifting, error reading, non-linearity etc.

The LCT-Ultimate is the only measuring tool required to perform the tests either on site or in the lab. Before you start, make sure to have the Load cell spec and the cable color code (usually you get it with the load cell, or it can be downloaded from the manufacture web site).

How to test a weighing platform with a few load cells:

  1. First stage: Leave all load cells connected to the summing box. Disconnect the cable from the weighing indicator, connect it to the LCT-Ultimate and perform a test.
     

  2. Expected results for a good scale are as per the following example: If you have 4 load cells of 1000Ω, 100kg each and 40kg are applied on the scale than you would expect to see around 250Ω for the input and output (total of the Input resistance divide by 4 and the same for the Output resistance). In case of six wires cable, you should expect to get very low resistance between the sense lines and the input as those are shorted inside the L/C.  Signal output must be around 10% (full scale capacity is 400kg) and the Shield to bridge resistance must remain very high i.e. >1000MΩ
     

  3. If some of the expected results are not in the required range, or you get erratic / unstable readings when testing in Continuous (Gain) mode: Check the cable integrity between the summing box and the tester. If it looks fine, disconnect each Load Cell cable and check each Load Cell separately. Note: there is no need to remove the load cell from the scale.
     

  4. If all results seem to be in range, you may check for scale linearity, by choosing Continuous mode (Gain) on the LCT-Ultimate and applying various weights on the scale.

Understanding the LCT-Ultimate results

Testing result with LCT-Ultimate

Input / Output resistance not in range

Possible reasons

Cable or connector problem

What to do?

Check cable integrity and the connectors

Testing result with LCT-Ultimate

Sense is Too high (6 wires cell)

Possible reasons

Not connected inside L/C, or it can be 4 wires Load Cell

What to do?

Replace or send for repair

Testing result with LCT-Ultimate

Input / Output resistance not in range

Possible reasons

Problems inside the load cell

What to do?

Replace or send for repair

Testing result with LCT-Ultimate

Signal Output from the scale is not in the expected range.

Possible reasons

Corrosion, force shunts, accumulated dust below the L/C or a faulty L/C

What to do?

Clean the dust and check force shunts and alignment. Replace L/C if necessary

Testing result with LCT-Ultimate

Signal Output not in the expected range (Unloaded Load Cell it should be around 0%)

Possible reasons

Load cell zero balance damaged because of shock or overload

What to do?

If the output signal is still low, the load cell can be used. A new calibration will be required.

Testing result with LCT-Ultimate

Shield to bridge is too low

Possible reasons

Water or chemical ingress to the cable or into the L/C

What to do?

Replace the cable or repair the L/C.

 ...Contact us

 sales1@ims.co.il  |  Tel: 04-8110877

Contact us

 sales1@ims.co.il  |  Tel: 972-48110877