Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 125
expecting a steady-state position error. (In contrast, setting Ixx33 to 0 prevents further inputs to the
integrator, but maintains the output.)
The Ixx63 integration limit can also be used to create a fault condition for the motor. If Ixx63 is set to a
negative number, then PMAC will also check as part of its following error safety check whether the
magnitude of integrated following error has saturated at the magnitude of Ixx63. With Ixx63 negative, if
the integrator has saturated, PMAC will trip (kill) the motor with a following error fault. Both the normal
fatal following error motor status bit and the integrated following error status bit are set when this fault
occurs. If Ixx63 is 0 or positive, the motor cannot trip on integrated following error fault.
To set Ixx63 to a value such that the integrator saturates at the same point that its contribution to the
command output causes saturation at the Ixx69 level, use the following formula:











30Ixx08Ixx
23
269Ixx
63Ixx
To cause trips, the magnitude of Ixx63 must be set to less than this value due to other potential
contributions to the output. Remember that the integrator stops increasing when the output saturates at
Ixx69.
Ixx63 is not used if the Extended Servo Algorithm for Motor xx is being executed (Iyy00=1).
Ixx64 Motor xx Deadband Gain Factor
Range: -32,768 - 32,767
Units: none
Default: 0 (no gain adjustment)
Ixx64 is part of the PMAC feature known as deadband compensation, which can be used to create or
cancel deadband. It controls the effective gain within the deadband zone (see Ixx65). When the
magnitude of the following error is less than the value of Ixx65, the proportional gain (Ixx30) is
multiplied by (Ixx64+16)/16. At a value of -16, Ixx64 provides true deadband.
Values between -16 and 0 yield reduced gain within the deadband. Ixx64 = 0 disables any deadband
effect.
Values of Ixx64 greater than 0 yield increased gain within the deadband; a value of 16 provides double
gain in the deadband. A small band of increased gain can be used to reduce errors while holding position,
without as much of a threat to make the system unstable. It is also useful in compensating for physical
deadband in the system.
Note:
Values of Ixx64 less than -16 will cause negative gain inside the deadband, making
it impossible for the system to settle inside the band. These settings have no
known useful function.
Outside the deadband, gain asymptotically approaches Ixx30 as the following error increases.
Ixx64 is not used if the Extended Servo Algorithm for Motor xx is being executed (Iyy00/50=1).
Ixx65 Motor xx Deadband Size
Range: -32,768 - 32,767
Units: 1/16 count
Default: 0
Ixx65 defines the size of the position error band, measured from zero error, within which there will be
changed or no control effort, for the PMAC feature known as deadband compensation. Ixx64 controls the
effective gain relative to Ix30 within the deadband.