Weighing equipment may have inaccurate weighing after long-term use. Generally, we need to solve this problem by calibrating the weighing controller. But sometimes no matter how we calibrate, the scale body cannot return to normal. At this time, we need to check in detail from all aspects of the weighing mechanism, and the core component of the weighing mechanism is the weighing sensor.

Current weighing equipment generally uses a resistance strain gauge weighing sensor (analog) as the core component of the weighing mechanism. It uses the Wheatstone bridge principle to convert the weight signal into a linearly changing electrical signal. There are four conventional lines, the input is 5-10V excitation voltage (power supply voltage), and the output is a weight signal in "mv". The following editor will show you how to judge the quality of the weighing sensor:

1、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.

2、Line input and output measurement method

Find the sensor connection terminal in the weighing controller (weighing instrument) and measure 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 equipment is unloaded, which is less than the maximum output of the sensor. (The maximum output of the sensor = excitation voltage * sensor sensitivity, the sensor sensitivity of the checkweigher is mostly 2mV/V). If it exceeds this range, contact the service provider to apply for a replacement sensor.

Sensor resistance measurement method:

Measure the sensor resistance and judge the quality of the sensor by the resistance

1: Input resistance ≧ output resistance > bridge resistance

2: In general, the bridge resistances are equal 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+ to SIG+, EXC+ to SIG-, EXC- to SIG+, EXC- to SIG-)

The above is the method to judge the quality of the weighing sensor in the weighing equipment. It should be noted that the weighing sensor is not so easy to damage under normal use. Many faults are caused by improper use of the scale body causing the weighing sensor to overload. Therefore, during the use and disassembly and maintenance of the weighing equipment, we should try to avoid heavy objects from hitting and bumping, and operate strictly according to the weighing range of the equipment.