Capacitance Probes Measure Gaps in Rotating Environments


[Application Note 72518]

Sensor environments are not always ideal. Across the various Gap sensor applications conditions may vary drastically. Some setups may have requirements of miniaturization, and others of wireless signal propagation. In rotating environments where cables cannot go, often there is a need for both.


Traditional sensing solutions can’t be used in environments requiring wireless propagation such as inside a rotating body. In these situations, the size and power requirements restrict the placement of sensor amplifiers to get accurate gap measurements in critical locations.

Rotating Cylinder

Could be a rotating drum


With MTI Instruments’ latest wireless gap sensor you can now place a small battery pack along with a miniature (10mm diameter) capacitance probe and get the critical gap data.

The 10 mm diameter probe face allows for a maximum 1.2mm range with a resolution of 5um.

Sensor settings allow you to change sensor performance on the fly. Whether you need 3 Samples a day for over a year in battery life or continuous sampling, The Wireless Gap sensor covers your requirements.


Built into your application the wireless system allows for minimal space usage while collecting critical data. Measure to a grounded target with the following characteristics:

  • Up to 5khz sampling ‚ÄìDefaults to min-max-avg returned @ 10Hz.
  • 5 ¬µm resolution
  • Linearity Ã¥ 0.25% FSR