PMAC Product Guide Jog Speed Jogging speed is specified by Ix22, which is a magnitude of the velocity, in counts per millisecond. Direction is specified by the jog command itself. Jog Commands The commands to jog a motor are on-line (immediate) commands that are motor-specific; they act on the currently addressed motor. Note: A jog command to a motor will be rejected if the motor is in a coordinate system that is currently executing a motion program, even if the motion program is not commanding that motor to move. PMAC will report ERR001 if I6 is set to 1 or 3.
Indefinite Jog Commands J+ commands an indefinite positive jog for the addressed motor; J- commands an indefinite negative jog; J/ commands an end to the jog, leaving the motor in position control after the deceleration. It is possible for the J/ command to leave the commanded position at a fractional count which can cause dithering between the adjacent integer count values. If this is a problem, the J! command can be used to force the commanded position to the nearest integer count value. Jogging to a Specified Position Jog commands to a specified position, or of a specified distance, can be given.
J= commands a jog to the last pre-jog position; J={constant} commands a jog to the (unscaled) position specified in the command; J=={constant} commands a jog to the (unscaled) position specified in the command and makes that position the pre-jog position; J^{constant} commands a jog of the specified distance from the actual position at the time of the command ( J^0 can be useful to take up remaining following error); J:{constant} commands a jog of the specified distance from the commanded position at the time of the command. Jog Moves Specified by a Variable Jogging moves to a position or of a distance specified by a variable are possible.
Each motor has a specific register (L:$082B for motor 1, L:$08EB for motor 2, etc.) that holds the position or distance to move on the next variable jog command. This register contains a floating-point value scaled in encoder counts. It should be accessed with an L-format M-Variable. The J=* command causes PMAC to use this value as a destination position. The J^* command causes PMAC to use the value as a distance from the actual position at the time of the command. The J:* command causes PMAC to use the value as a distance from the commanded position at the time of the command.
Each time one of these commands is given, the acceleration and velocity parameters at that time control the response to the command. To change speed or acceleration parameters of an active jog move, change the appropriate parameters, then issue another jog command. Jog-Until-Trigger The jog-until-trigger function permits a jog move to be interrupted by a trigger and terminated by a move relative to the position at the time of the trigger. It is similar to a homing search move, except that the motor zero position is not altered, and there is a specific destination in the absence of a trigger.
The jog-until-trigger function for a motor is specified by adding a ^{constant} specifier to the end of a regular definite jog command for the motor, where this {constant} is the distance to be traveled relative to the trigger position before stopping, in encoder counts. It cannot be used with the indefinite jog commands J+ and J- . 56 Programming PMAC