Principle of Operation
- 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.