The design of clamping force measuring instrument based on MSP430 microcontroller

摘要

In the injection molding machine industry, because of the current situation of the low precision of the clamping force measurement, the design of a clamping force measuring instrument based on MSP4305438 microcontroller is proposed. Firstly, the system is connected with 4 magnetic adsorption force sensors, and the detection method of sensor is the resistance strain gauge measuring method. Adopting low power microcontroller MSP430F5438 as the core, by low pass filter circuit as well as AD7708 amplification and conversion circuit, the system measures the differential voltage of Wheatstone bridge on the 4 Green columns of injection molding machine. The corresponding strain and stress are obtained, and there are the function of storage and communication, in order to communicate with the PC terminal for real-time monitoring dates. Therefore, the system uses the method of detecting Green column variables directly to obtain the clamping force, which makes the detection result more accurate. The absolute error of the measurement result can be controlled within +0.06kN, the instrument measurement accuracy can be up to 0.1%. Consequently, the working state of the injection molding machine can be obtained timely and accurately, and the defective rate of products and the wear of moulds are reduced effectively.