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  • my ifm
  1. SDP gap distance sensor
  2. Setup and support
  3. Installation guidelines

SDP gap sensor: Installation guidelines

For best performance of the SDP gap measurement sensor, please adhere to the guidelines below. More details are availble in the operating manual found on the product datasheet page.

Operating pressure

The SDP requires 14.5...44 psi (1...3 bar) for best accuracy when measuring a gap distance.

  • If you are not interested in monitoring the distance, e.g., during purging of the system, the sensor is rated for 232 (16 bar) and will measure pressure up to that limit.

Direction of flow

The thermal measuring principle does not provide the ability to determine which way the air is flowing. However, direction of flow ensures there is enough straight pipe run leading into the sensor to provide reliable measurements. When installing the unit, follow the directional arrow on the body of the sensor.

Orientation

The installation orientation of the SDP sensor is very flexible. All orientations shown in the image are acceptable except when the unit is installed with the pipe to the left of the sensor head (bottom right image). The SDP is designed so that one of the probes is heated (the bottom probe in the image). With the heated probe on the bottom, as the heat rises toward the measuring probe, it can influence the flow measurement and therefore skew the calculated distance measurement. 

Installation relative to the air nozzles

Because thermal flow measurement is affected by moisture and particle content in the compressed air supply, always mount the SDP sensor higher than the air nozzles. This ensures no condensation or particles adhere to the measuring probes.

ifm does not sell fittings to connect the SDP to your air tubing. We recommend using Festo QS-G1/4-6 (6 mm tubing) or QS-G1/4-8 (8 mm tubing) or equivalent push fittings.

Nozzle geometry

ifm does not supply air nozzles. Generally nozzles are fabricated as part of a machining fixture. Please adhere to the following geometry:

  • The nozzle should be 1.5 times longer than the outlet diameter.
  • The bore hole should be 2.5 times the diameter of the nozzle outlet.
  • The taper from the bore to the nozzle should be 120º.
  • The nozzle outlet should have a sharp edge.