As an alternative to the workaround described above, I've found that SoftMotion parameter dwBusModuloMask may be used to force rollover of the position command at a value compatible with the internal drive modulo. This approach will (in typical cases) allow us to retain the drive's absolute position reference while maximizing the internal position resolution. For example, setting dwBusModuloMask = 2^18 - 1 = 262143, we may configure the axis as follows: Running the cam described in the original post now yields the following. Note that the position command value rollover now corresponds with the actual drive position. I've tested this configuration for 4+ hours and see no problems and no position drift. Moreover, the position is retained on program restart or power cycle. Both forward and backward operation has been verified. @eschwellinger: Am I missing anything? Was there a specific reason you did not suggest adjusting dwBusModuloMask? Also, following the documentation I've assigned dwBusBandWidth a value of 262144 = 2^18. What does this parameter do?
... View more