Checking Load Cell Connections

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

Measurement location		Measurement	Notes
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.