CLOSED LOOP SOLDER WAVE HEIGHT CONTROL SYSTEM

摘要

An apparatus for processing printed circuit boards including a system for measuring and controlling solder wave height generally comprises conveyor system for transporting printed circuit board through a number of processing stations. The system for measuring and controlling the wave height of solder includes a sensor which is mounted in close proximity to the interface defined between the surface of the solder wave and the bottom surface of the printed circuit board. The sensor is coupled to a micro-controller and the micro- controller is coupled to a pump motor. The pump motor is coupled to a solder bath which generates the solder wave and is controlled to operate at a predetermined speed to maintain a predetermined solder wave height during the process of wave soldering printed circuit boards. The sensor provides a number of voltages to the micro-controller representing the distance between the sensor and the top surface of the solder wave. The voltages are converted into a number of values. The micro-controller includes a comparator which receives the values and compares the values to a predetermined set point to determine whether the solder wave height is too high or too low and the micro-controller further determines whether to respectively decrease or increase the speed of the pump motor.