Line failure manifests itself as the controller indicating value overflowing, displaying error messages, and the signal suddenly interrupting or jumping randomly during weighing. There are two reasons:

First, the connection line between the sensor and the control instrument is broken. This external fault is mainly caused by improper installation and use. If you use a multimeter to check the sensor input and output resistance, the resistance values ??are normal. The cause of the failure is: the connecting wire is broken, causing an open circuit; the connecting wire joint is loose or not soldered firmly, etc.

Second, there is a problem with the quality of the sensor itself. It manifests as changes in sensor input and output resistance. Under normal circumstances, the input resistance of the sensor is 400Ω±10Ω, and the output resistance is 350Ω±3Ω. The main faults of the sensor are that the terminals or lead wire solder joints fall off; the sensor zero point temperature compensation or sensitivity temperature compensation resistor is soldered or desoldered; the sensor is not sealed well and the internal chip is damp.

Abnormal zero point of electronic scales is also a common fault. One of the reasons is that the sensor is not temperature compensated. The zero point and sensitivity of the sensor change with changes in ambient temperature, causing the zero point of the electronic scale to malfunction. According to international standards, there is a temperature compensation process in the sensor production process, and the sensor should be simulated through a high and low temperature chamber. Environmental temperature changes are used for compensation, but many domestic sensor manufacturers do not have high and low temperature chambers at all and cannot perform temperature compensation on the sensors. The second reason is that the sensors are severely overloaded, causing plastic deformation of the elastomer and damage to the sensors.

In addition, water, moisture, oxidation or resistor breakdown in the junction box may cause major failures.

The above is an analysis of common system failures of concrete batching machines. I hope to help you solve some problems.