Power Brick Controller User Manual
Special Functions & Troubleshooting
178
Sinusoidal Encoder Bias Corrections
Before computing the sub-count interpolated position with the arctangent calculation, the PMAC3-style
ASIC can add in offset terms to the measured values in the ADC registers to compensate for voltage biases
in the encoder and/or receiving circuitry.
Excessive biases due to scale/read head misalignment, noise, or mechanical assembly may result in rough
motion, visible velocity harmonics, and or encoder count loss. This is best seen with an open loop test:
Uncorrected
Corrected
Note
Corrections with the ACI (Auto Correcting Interpolator) are done
automatically for both offsets and phase. This procedure is only
suitable when interpolating with the DSPGate3 (x16384) – without
the ACI option.
