- The formula to convert accuracy and repeatability stated in ARCSECONDS, to
accuracy in inches, at a specific radius is
- Example: A Camco 902 RDM has an accuracy of 69 ARCSECONDS. At a 12 inch radius, how accurate is it?
- 69 ARCSEC x 1 minute x 1 degree = 0.0192 degree:
- 60 SEC x 60 minutes
- 12 inches x 2 x 3.14159 = 0.2095 inches per degree
- 360 degrees
- 0.0192 degrees x 0.2095 inches per degree = 0.0041 inches
- Therefore, at a 12 inch radius, the CAMCO 900 RDM has an accuracy of 0.0041 inches.
The rated operating distance specifications listed in most manufacturer's
catalogs of inductive proximity sensors, do not necessarily state the actual
operating distance you will get.
- The rated operating distance is based on standard targets of a specific size and material
- Material: Mild Steel
- Thickness: 0.04 Inch (1MM)
- Shape: Square
- Size: The length and width are equal to either:
The target approaches the sensor along the reference axis, from the front, not from the sides.
Temperature fluctuations, voltage variations, and manufacturing tolerances can affect the operating distance by +/- 20% (0.8 - 1.2 x Rated Operating Distance)
Therefore, the assured operating distance of any inductive proximity sensor is 0 - 80% of the Rated Operating Distance provided you are sensing a
For typical non-standard targets, you must de-rate the sensors by the following factors:
- The diameter of the circle inscribed on the active surface
of the sensing face, or
- Three times the rated operating distance, whichever is greater.
- Aluminum (Solid) 0.35 to 0.5
- Aluminum (Foil) 1.00
- Brass 0.35 to 0.5
- Copper 0.25 to 0.45
- Lead 0.5 to 0.75
- Mercury 0.65 to 0.85
- Stainless Steel 0.6 to 1.00
or check out the patented UPROX sensor from the Turck. It senses all types of Metals at the same distance.