Reference Manual

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PMAC 2 Software Reference

PMAC On-Line Command Specification 241

Remarks

This command format permits a jog-until-trigger function. When the ^{constant}

structure is added to any definite jog command, the jog move can be interrupted by a pre-

defined trigger condition, and the motor will move to a point relative to the trigger position as

specified by the final value in the command.

The indefinite jog commands J+ and J- cannot be turned into jog-until-trigger moves.

Jog-until-trigger moves are very similar to homing search moves, except they have a definite

end position in the absence of a trigger, and they do not change the motor zero position. In

the absence of a trigger, the move will simply stop at the pre-defined position.

The trigger condition for a jog-until-trigger move can be either an input flag, or a warning

following error condition for the motor. If bit 17 of Ix03 is 0 (the default), the trigger is a

transition of an input flag and/or encoder index channel from the set defined for the motor by

Ix25. Encoder/flag variables 2 and 3 (e.g. I912 and I913) define which edges of which input

signals create the trigger.

If bit 17 of Ix03 is 1, the trigger is the warning following error status bit of the motor

becoming true. Ix12 for the motor sets the error threshold for this condition.

The trigger position can either be the hardware-captured position, or a software-read position.

If bit 16 of Ix03 is 0 (the default), the encoder position latched by the trigger in PMAC’s

DSPGATE hardware is used as the trigger position. This is the most accurate option because

it uses the position at the moment of the trigger, but it can only be used with incremental

encoder feedback brought in on the same channel number as the triggering flag set. This

option cannot be used for other types of feedback, or for triggering on following error.

If bit 16 of Ix03 is 1, PMAC reads the present sensor position after it sees the trigger. This

can be used with any type of feedback and either trigger condition, but can be less accurate

than the hardware capture because of software delays.

Jogging acceleration and velocity are determined by the values of Ix19-Ix22 in force at the

time of this command.

PMAC will reject this command if the motor is in a coordinate system that is currently

running a motion program (reporting ERR001 if I6 is 1 or 3).

Example

#1J=^1000 .. ; Jog to pre-jog position in the absence of a trigger, but if trigger

........................... ; is found, jog to +1000 counts from trigger.

#2J:5000^-100 ; Jog 5000 counts in the positive direction in the absence of a

........................... ; trigger, but if trigger is found, jog to -100 counts from

........................... ; trigger position.

#3J=20000^0. ; Jog to 20000 counts in the absence of a trigger, but if

; trigger is found, return to trigger position.