calibration of load cell theory

The core idea is to establish a known relationship between the applied force and the sensor's electrical output. You apply a series of precise reference loads and measure the corresponding output signals. From there, you create a calibration curve—often a linear or polynomial equation—that lets any future output signal be accurately converted back into a force value.

Hysteresis means the output for a given load depends on whether the load is increasing or decreasing. During calibration, you typically take readings during both loading and unloading to characterize this effect. A good calibration method then uses algorithms to minimize hysteresis error. Many of Kingmach's sensors are designed with materials and strain gauge bonding that keep hysteresis low from the start.

There's no one-size-fits-all answer. In stable laboratory conditions, annual checks may be enough. In geotechnical field work with temperature swings and long-term monitoring, more frequent verification is wise. A good practice is to do a quick system check—like a shunt calibration—before each measurement campaign, and a full recalibration with reference weights every six to twelve months, or whenever data drift is suspected.

Partially. Many load cells include temperature compensation built into the strain gauge bridge, which reduces the zero shift and sensitivity change over a specified temperature range. Calibration performed at the expected operating temperature helps, and for high-accuracy work, you might establish correction factors at multiple temperatures. Kingmach's calibration data often includes temperature coefficients that allow software compensation.

Factory calibration is done under controlled conditions using highly accurate reference machines. It provides a baseline certificate traceable to national standards. Field calibration verifies that the sensor and its mounting, cabling, and instrumentation perform correctly on site. It's usually less precise but essential to catch installation errors or long-term drift. Kingmach recommends both—starting with the factory certificate and periodically confirming with a field check.