Reference Manual

Turbo PMAC/PMAC2 Software Reference

Turbo PMAC On-line Command Specification 275

 The motor home complete status bit is cleared.

 The motor position bias register, which contains the difference between motor and axis zero

positions, is set to 0.

 If Ixx10 for the motor is greater than 0, specifying an absolute position read, the sensor is read as

specified by Ixx10 and Ixx95 to set the motor actual position. The actual position value is set to the

sum of the sensor value and the Ixx26 “home offset” parameter. Unless the read is determined to be

unsuccessful, the motor “home complete” status bit is set to 1.

 If Ixx10 for the motor is set to 0, specifying no absolute position read, the motor actual position

 Because the motor is killed the actual position value is automatically copied into the command

position register for the motor.

 There are several things to note with regard to this command:

 The motor is left in the killed state at the end of execution of this command. To enable the motor, a $

command should be used if this is a PMAC-commutated motor and a phase reference must be

established; otherwise a J/, A, or <CTRL-A> command should be used to enable the motor and close

the loop.

 If bit 2 of Ixx80 is set to 1, PMAC will not attempt an absolute position read at the board power-

on/reset; in this case, the $* command must be used to establish the absolute sensor. If bit 2 of Ixx80

is set to 0 (the default), PMAC will attempt an absolute position read at the board power-on/reset.

 With Ixx10 set to 0, the action of $* is very similar to that of the HOMEZ command. There are a few

significant differences, however:

 $* always kills the motor; HOMEZ leaves the servo in its existing state.

 $* sets the present actual position to be zero; HOMEZ sets the present commanded position to be

zero.

 $* zeros the hardware encoder counter in most cases; HOMEZ does not change the hardware

encoder counter.

 All of the motors in a single coordinate system that require an absolute position read can be

commanded at once with the coordinate-system specific $$* command.