Line Resolution defines the length of material movement for each increment of the encoder.
It is a function of the circumference of the measuring wheel and the number of counts per revolution of the encoder. The formula for calculating Line Resolution is:
Resolution = Circumference
4 x Encoder Count
For an AMS encoder, the count of the encoder is the model number of the encoder. Being a quadrature encoder, the PPR (pulses per revolution) is 4 times the number of counts. For example, a Model 256 is a 256-count encoder with 1024 PPR; a Model 1000 is a 1000-count encoder with 4000 PPR.
The most common wheel used has a circumference of 12 inches. For this size wheel, Line Resolution is:
| Model Encoder | Resolution (W/ 12” Wheel) |
| Model 256 | .00171875 |
| Model 500 | .006 |
| Model 1000 | .003 |
| Model 2000 | .0015 |
It is not necessary to precisely measure the circumference or calculate the formula to any great precision. Nominal values can be used, and precise results are achieved during calibration. Values between 0.00004000” and 0.04000000” are acceptable.