Encoder Resolution Calculator
Calculate the angular and linear resolution of an encoder based on CPR or PPR.
encoder
resolution
CPR
PPR
angular
degrees
PLC
HSC
Input values
⚙
Enter values and click Calculate to see results here.
Formula
Angular resolution = 360 / CPR
Linear resolution = π × D / CPR
Worked Example
Given: An encoder with 1024 CPR is mounted on a 50 mm diameter shaft.
Step 1: Angular resolution = 360 / 1024 = 0.3516°
Step 2: Linear resolution = π × 50 / 1024 = 0.153 mm
This means the system can detect a minimum rotation of 0.35° or 0.153 mm of linear movement.
Engineering Notes
- CPR vs PPR: CPR = Counts Per Revolution (after quadrature). PPR = Pulses Per Revolution (before quadrature). CPR = PPR × 4 for x4 decoding.
- Sufficiency: For most position control, 100-1000 CPR is adequate. For high-precision machining, use 2500+ CPR.
- Noise immunity: Higher resolution encoders produce more pulses per second. Verify your PLC HSC can handle the maximum frequency: Max freq = CPR × Max RPM / 60.
- Backlash: Encoder resolution does not account for mechanical backlash in gearboxes or couplings. The mechanical system may limit actual precision.
References
- IEC 60034-8 — Terminal markings and directions of rotation