DWELL AND BACK PRESSURE SENSING DEVICE FOR MOTORIZED INJECTION MOLDING MACHINE

摘要

PURPOSE:To control dwell and back pressure with good accuracy by disposing a signal processing section close to a load cell as a pressure sensor, selecting first and second amplifiers corresponding to the metering process and dwelling process, turning output signals of said amplifiers into digital and transferring the same to a control device. CONSTITUTION:In the metering process, a back pressure command signal is applied from a control device 16 to a dwell and back pressure selector switch 18 through a receiver circuit 17, and the dwell and back pressure selector switch 18 selects a back pressure voltage signal. An A/D converter 20 converts a sample back pressure voltage signal into a back pressure digital signal. Similarly in the dwelling process, the dwell and back pressure selector switch 18 selects the dwell pressure voltage signal based on the dwell pressure command signal from a control base 16. The A/D converter 20 converts a sample dwell pressure voltage signal into a dwell pressure digital signal. Back pressure data and dwell pressure data are transferred by using a line driver and a photocoupler. The transmission of noise generated by ground loop or the like can be prevented.