load cell circuit

Most foil strain gauge load cells run on 5 to 10 V DC. Using a regulated excitation voltage is essential, because any drift in the supply directly shows up as a drift in the reading. Kingmach’s circuits use low-noise, low-temperature-coefficient references to keep excitation stable.

In addition to twisted-pair, shielded cable, the circuit should have a differential input with high common-mode rejection. Kingmach’s modules filter out power-line noise at the input and can drive a 4–20 mA current loop for distances over 100 meters, which is much less susceptible to interference than a voltage signal.

Yes. By setting the zero point to mid-range and using a bipolar supply or a virtual ground, the same circuit can measure forces in both directions. Our instruments typically have a programmable zero offset that you can configure through the digital interface.

We combine passive and active methods. The bridge completion resistors are selected for low tempco, and a digital temperature sensor on the board lets the microcontroller apply gain correction based on a calibration table stored for each sensor. This keeps the accuracy within spec over a wide ambient range.

With proper circuit design, recalibration intervals can be extended. Our systems typically hold calibration for a year or more in stable installations. However, if the sensor undergoes shock loads or extreme thermal cycles, we recommend a field check with a shunt calibration resistor to verify the circuit’s health.