Speed monitoring system

for pumps

The Pump RPM monitor system monitors the speed of the solder pump. If a problem arises that affects the speed of the impellor, the sensing system will detect this change, stop the pump running and display an error message. The type of sensor that is fitted to this PCB is a “Self Calibrating Hall Effect Fine Tooth Gear Sensor”. The output from this sensor is a current pulse, which is then converted to a voltage on the head controller. This then compared to a reference voltage. The system can then detect open circuit, short circuit and pulse conditions. The time between each revolution of the pulley is measured by the hardware, and then this time is used to calculate the pump RPM. Because there is only one pulse per pulley revolution, the sensor is only accurate to within ±2rpm. For this reason the sensor is not used to display the pump running rpm, but only informs the system if there is a pump speed error.