Frequently Asked Questions Related to Electromagnetic Detector

When connecting an MP series electromagnetic detector to devices such as a rotary meter or FV converter, if the signal is unstable due to noise, it may be effective to add a capacitor to the input signal terminals as a noise countermeasure. By adding a capacitor, a low-pass filter is formed, which helps to reduce high-frequency noise.

Malfunctions caused by noise on the signal are particularly noticeable when the signal is near zero, as shown in the figure below. The MP series electromagnetic detectors may be especially affected by noise at low rotation speeds because the signal amplitude is small.

The voltage sensitivity of TM series tachometers and FV converters is 0.2Vrms (equivalent to 0.56 Vp-p) for AC signals. The capacitor capacity is selected based on the balance between the signal amplitude in the operating rotation range and the sensitivity of the equipment.

In the MP series electromagnetic detector, the signal amplitude changes due to rotation speed and installation gap, and the influence of stray capacitance in the signal line and the receiving circuit must also be considered, making it unclear what the amplitude characteristics will be. It is necessary to adjust the capacitor while checking the signal with an oscilloscope.