PPMAC - Disable limits not supported

[LeandroMartinsdS]

In TurboPMAC, the limits are monitored by examining the ix24 variables. However, in PowerPMAC, ix24 represents the address of the servo-loop being used. PowerPMAC also includes protection against writing to invalid addresses. The element Motor[%d].pLimits should be used instead.

This difference makes operations like i%d24=i%d24&$FDFFFF and i%d24=i%d24|$20000 invalid in PowerPMAC. Moreover, these operations do not disable or enable the limits as one might expect. The correct operation should be something like Motor[%d].pLimits=0 for disabing, and Motor[%d].pLimits=Gate3[%d].Chan[%d].Status.a for enabling (preferably that address should be stored when disabling the limits).

When checking ix24, the response formats differ between TurboPMAC and PowerPMAC:

• TurboPMAC uses the $%x format.
• PowerPMAC uses the %d format.

Ultimately, these differences might lead to undesired behavior in two scenarios:

• When homing into the limits, which is necessary to disable the limit faults.
• When performing a safety check present in pmacAxis::getAxisStatus, which flags if the limits are disabled without the driver’s knowledge.