Causes of magnetostrictive sensor problems

Magnetostrictive sensors, whether SSI, Start/Stop, or PWM, are rugged sensors, but like everything else, can fail. Troubleshooting can be difficult, and the symptoms can vary widely. At Delta, we say that the normal symptoms of a failed magnetostrictive sensor is “weird behavior”.

Here is a list of behaviors and causes we have encountered:

  1. Intermittent signal.

    • Internal wear due to vibration.
    • Bad cable.
  2. No signal.

    • Bad magnet
  3. Regular noise

    • Noisy power supply.
  4. Good signal, but doesn’t follow cylinder always.

    • Magnet fell off piston.
  5. Signal follows, but has lots of jumps of and down.

    • SSI Gray/Binary code setting is wrong in RMC.

Key Words: MDT, transducer, linear sensors, issues