4-wire / 6-wire technology

The load cell itself and the connecting cable form a voltage divider, i.e. the higher the cable resistance, the lower the voltage at the strain gauges of the force transducer. A lower voltage at the Wheatstone bridge leads to a lower output signal: The characteristic value of the force sensor therefore changes with the resistance of the supply cable.

In the 6-wire circuit, the voltage is measured directly at the strain gauge bridge using two additional leads and corrected if necessary, which is why the sensitivity (the characteristic value) is independent of the lead length or temperature. A particularly favourable feature is that the lead resistance is continuously adjusted, i.e. even if the lead resistance changes due to temperature or a change in cable length, this has no influence on the sensitivity of the sensor. The 6-wire technology is used particularly for high-precision sensors.
If a force transducer wired in 6-wire technology is to be connected to a measuring amplifier with 4-wire technology, we recommend short-circuiting the sensor leads with the corresponding supply voltage leads. The ohmic resistances of the supply line are then lower, which reduces the voltage drop on the supply line - and thus the influence of the cable length and any temperature influences.

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