Factors that affect the measurement accuracy of the weighing sensor of the mixing station

1 External influence factors

The commercial concrete mixing station for hydropower station construction is installed on the construction site. The site environment is harsh, and many factors such as ambient temperature, humidity, atmospheric pressure, vibration, magnetic field, electric field and so on may introduce energy conversion errors, cause zero drift and sensitivity changes. In the course of use, the sensor structure, capacity, technical parameter selection, material setting, and unreasonable installation process will also cause errors in the measurement results and even increase the damage rate of the sensor. Therefore, the manufacturing verification index of the load cell cannot be equal to the accuracy and other performance indexes of actual use. Although the sensor manufacturing technology is constantly improving, the use technology of the load cell must not be ignored. When the use conditions change, measures must be taken to limit various error sources.

2 internal factors

The load cell of commercial concrete batching plant currently generally adopts the resistance strain type. Its working principle is based on the elastic deformation of the elastic body (elastic element) under the action of external force, so that the resistance strain gauge (conversion element) pasted on its surface also deforms at the same time. , Which causes the resistance of the strain gauge to change (increase or decrease), and then convert the change in resistance into an electrical signal (voltage or current) through the corresponding measurement circuit, and output an electrical signal proportional to the weight to achieve measurement The purpose of weight. Therefore, the manufacturing process quality of elastomers, resistance strain gauges, strain glues and measuring circuits is the key to the measurement accuracy of load cells.

The elastomer is a structural member with a special shape. It has two functions. The first is that it bears the external force of the load cell, and the second is that it generates a high-quality strain zone so that the resistance strain pasted in this zone can complete the signal conversion task. Therefore, it can be said that the metal material of the elastomer, the forging, machining, heat treatment and surface treatment of the metal material are supporting processes to ensure the measurement accuracy of the load cell. It determines the hardenability, strength and toughness, and fatigue strength of the elastomer. Wait. The resistance strain gauge is the core element of the load cell. Its working principle is based on the resistance strain effect of the material, and it is pasted on the elastic element of the sensor with an adhesive. Its own manufacturing process and strain gauge adhesive (strain glue) are the basic processes to ensure the measurement accuracy of the load cell; the resistance strain gage paste, curing, bridge assembly, protection and sealing, circuit compensation and adjustment are to ensure the measurement accuracy of the load cell The core process. From pasting to circuit compensation, no matter which process is not good enough, even if you use a good strain gauge, it will not help.