4-wire / 6-wire technology

The load cell itself and the connecting cable form a voltage divider; in other words, the higher the cable resistance, the lower the voltage across the strain gauges of the load cell. A lower voltage across the Wheatstone bridge in turn results in a lower output signal: the load cell’s sensitivity therefore varies with the resistance of the connecting cable.
In a 6-wire configuration, the voltage is measured directly across the strain gauge bridge using two additional wires and corrected where necessary; this is why the sensitivity (the characteristic value) is independent of cable length or temperature. This is made possible by the continuous compensation for cable resistance – changes due to temperature or cable length therefore do not affect the sensitivity.

The 6-wire technique is used particularly with high-precision sensors.
If a load cell wired using the 6-wire technique is to be connected to a measuring amplifier using the 4-wire technique, we recommend short-circuiting the sensor leads to the corresponding supply voltage leads. This reduces the ohmic resistance of the supply line, which in turn reduces the voltage drop across the supply line – and thus minimises the influence of cable length and any temperature-related effects.

If you need to measure very accurately with an amplifier using 4-wire technology, it is advisable to calibrate the measuring chain in order to eliminate the influence of the cable during calibration.
In the case of force transducers designed using 4-wire technology, the connecting cable is part of the calibration network - you should not shorten the cables and, if possible, extend them using 6-wire technology so as not to impair the sensitivity and the temperature influence on the characteristic value.

Frequency influence of the supply voltage on the zero signal [%]

Maximum deviation of the zero signal related to the nominal characteristic value by changing the carrier frequency of the supply voltage. The frequency range must be specified.

Frequency influence of the supply voltage on the characteristic value [%]

Maximum deviation of the characteristic value related to the nominal characteristic value by changing the carrier frequency of the supply voltage. The frequency range must be specified.

Operating range of the supply voltage [V]

Range of the supply voltage in which the force transducer can be operated while allowing for larger error limits without permanent significant changes in its metrological properties being detected when the transducer is reused in the nominal range of the supply voltage.
Note: In the case of force transducers with integrated electronics, these provide the supply voltage for the strain gauge. The integrated electronics are operated with the supply voltage, usually 12 V DC or 24 V DC.

Insulation resistance [Ω]

Ohmic resistance, measured between the connecting cables and the deformation body of the force transducer, specifying the test voltage

Calibration check [CC]

For amplifiers with a current output of 4 - 20 mA, the CC is usually set as follows:
CC-Hub = NP+16 mA
CC-absolute = 20 mA
Measure the CC resistance using the resistance decade and set to 20 mA.
If the "CC" button is pressed on the KK-0040, the nominal output signal is switched on.
CC is connected to GND (low active) --> Test the functionality of e.g. a switch-off device without real load on the sensor.

Nominal range of the supply voltage [V]

Range of the supply voltage in which the force transducer complies with the error limits of its technical data.

Supply voltage influence on the zero signal [%]

Change in the zero signal of the nominal characteristic value of the force transducer as a result of a change in the supply voltage in the nominal range of the supply voltage BU, nom.

Supply voltage influence on the characteristic value [%]

Relative change in the characteristic value of the force transducer due to a change in the supply voltage in the nominal range of the supply voltage BU, nom.

Supply voltage [V]

Operating voltage (mains or battery supply) of the measuring amplifier of the measuring chain