A load cell is actually a device that converts a mass signal into a measurable electrical output. With the sensor, we must first consider the actual working environment of the sensor, which is crucial to the correct selection of the weighing sensor, which is related to whether the sensor can work normally and its safety and service life, and even the reliability and safety of the entire weighing device. There are qualitative differences between old and new countries in the basic concepts and evaluation methods of the main technical indicators of weighing sensors.

Weighing sensor good or bad judgment

Weighing equipment after a long time of use may appear inaccurate weighing phenomenon, generally we have to calibrate the weighing controller to solve such problems. But sometimes no matter how calibration can not let the scale body return to normal, then we have to check in detail from all aspects of the weighing mechanism, and the core component of the weighing mechanism is the weighing sensor.

The current weighing equipment generally adopts the resistance strain gauge type weighing sensor (analog) as the core component of the weighing mechanism, which uses the bridge principle to convert the weight signal into a linear change of electrical signal, and generally has four lines, the input is 5-10V excitation voltage (supply voltage), and the output is the weight signal in "mV".

One: observation method

Observe whether the appearance of the sensor is deformed, cracked, etc. If these conditions occur, you need to contact the manufacturer to replace the new sensor.

Two: line input and output measurement method

Locate the sensor connection in the weighing controller (weighing instrument) and determine the sensor connection circuit

Under normal circumstances, the excitation voltage (between EXC and EXC-) is 5-10V, and the output voltage (between SIG and SIG-) is close to 0 when the device is unloaded, which is less than the larger output of the sensor. (Sensor larger output = excitation voltage * sensor sensitivity, the sensor sensitivity of the weight scale is mostly 2mV/V), beyond this range, contact the service provider to apply for the replacement of the sensor.

Three: Sensor resistance measurement method:

Measure the resistance value of the sensor, and determine the quality of the sensor by the resistance value

1: Input resistance ≧ output resistance > bridge resistance

2: In general, the bridge resistance is equal to or equal to each other

(Note: Input resistance is the resistance between EXC and EXC-, output resistance is the resistance between SIG and SIG-, bridge resistance is the resistance between EXC and SIG-, EXC to SIG-, EXC- to SIG-, EXC- to SIG-)