A unique application of CPI SL series is to accurately sense the pre-charge pressure inside a hydraulic piston accumulator.

Because piston seals are dynamic, they are subject to wear and eventually will leak. This can cause the piston to drift, so even though a pressure transducer may indicate the correct pressure, the piston may not be where it should based on the pressure. If the piston is too close to the end cap, then a sudden increase in system pressure could cause the piston to slam into the end cap. Many designers will actually extend the stroke length of their cylinders unnecessarily, simply to allow for piston drift over time.

CPI sensors alleviate these challenges by being able to provide absolute piston position inside the accumulator.  Unlike other sensor technologies which need to be zero calibrated frequently for accurate relative offset measurement, CPI sensors can provide absolute position, allowing control systems to allow for piston drift, while providing a more robust overall measurement system. The sensors can be deployed on the oil, or the gas side of the sensor and use an LVDT based sensing mechanism that is almost completely immune to shock, vibration, and EMI.