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Description:
The drivePll module was improved to lock for a wider range of driveUpdatePeriod:controllerPeriod ratios and greater initial period error. This upgrade allows up to a 32:1 ratio and initial error of up to 16 clocks (0.640 us). This upgrade will reliably lock for any drive update period or controller period supported in any software release to date. Prior to this upgrade, the drive interface for some nodes failed to lock for some controller sample rates.
For example, a drive with 16 kHz period (such as S200) would not reliably lock to the controller rate of 1066 Hz. This configuration has a 15:1 driveUpdatePeriod:controllerPeriod ratio, and for various software reasons has a larger-than-normal initial period error. Problem ratios (and controller periods assuming a 16 kHz drive update period) are: 15:1 (1066 Hz), 14:1 (1142 Hz), 13:1 (1230 Hz). Marginal ratios are: 12:1 (1333 Hz), 11:1 (1454 Hz), 9:1 (1777 Hz), and 7:1 (2285 Hz). The marginal ratios may fail depending on the accuracy of the controller and node oscillators. When drivePll acquistion fails, the drive will not get the cyclic flag Drive_Strobe_Lock=1, and will not return the cyclic status Drive_Ready=1. The motor status indicates Amp_Fault and the motor cannot be enabled.
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