After wiring a load cell, have you ever wanted to check that the connections are correct?
You can easily check load cell wiring with a digital multimeter. The following diagram shows where to measure when a single load cell is connected to an indicator. When a summing box is used to connect multiple load cells, similar measurements can be made using the terminal blocks inside the summing box.
Measurements to Check Load Cell Connections
|EXC+||SEN+||Voltage drop of load cell EXC+||While usually 100 mV or less, this value may exceed 1 V when extremely long load cell cables are used.|
The value is 0 V for four-wire cables, since they have no SEN+ wires.
|EXC+||EXC-||Excitation voltage for load cell||The result depends on the type of weighing indicator but 5 V and 10 V models are most common.|
Check the excitation voltage specification of the indicator.
|SEN-||EXC-||Voltage drop of load cell EXC-||This value is the same as for EXC+ and SEN+ above.|
|SIG-||EXC-||Median voltage of the load cell||Approximately half the excitation voltage.|
|SIG+||SIG-||Output voltage of load cell||Compare with theoretical values obtained from the rated output, actual load, and excitation voltage of the load cell.If the excitation voltage is 5 V, this value is 0 to 15 mV.|
If the excitation voltage is 10 V, this value is usually in the range of 0 to 30 mV.