Reference Manual

PMAC 2 Software Reference
26 PMAC I-Variable Specifiation
ERR017
Motor(s) in C.S. not at halted
position to restart after / or \
command
(should move motor(s) back to halted
position with J=)
See Also
Talking to PMAC
Writing a Host Communications Program
I-variables I3, I4
On-line commands R, S
I7 In-Position Number of Cycles
Range
0 .. 255
Units
Background computation cycles (minus one)
Default
0
Remarks
I7 permits the user to define the number of consecutive scans that PMAC motors must
satisfy all “in-position” conditions before the motor in-position bit is set true. This permits
the user to ensure that the motor is truly settled in the end position before executing the
next operation, on or off PMAC. I7 + 1 consecutive scans are required.
PMAC scans for the in-position condition of each active motor during the “housekeeping”
part of every background cycle, which occurs between each scan of each enabled
uncompiled background PLC (PLC 1-31). All motors in a coordinate system must have
true in-position bits for the coordinate-system in-position bit to be set true.
See Also
Control Panel Port (Connecting PMAC to the Machine)
Using Interrupts (Writing a Host Communications Program)
I-variable Ix28
On-line commands ?,??
Suggested M-variable definitions Mx40
Memory registers Y:$0814, Y:$08D4, etc., Y:$0817, Y:$08D7, etc.
DPRAM Control Panel Functions
JPAN connector
I8 Real Time Interrupt Period
Range
0 .. 255
Units
Servo Interrupt Cycles
Default
2
Remarks
I8 controls how often certain time-critical tasks, such as PLC 0 and checking for motion
program move planning, are performed. A value of 2 means that they are performed after
every third servo interrupt, 3 means every fourth interrupt, and so on. The vast majority of
users can leave this at the default value. In some advanced applications that push PMAC’s
speed capabilities, tradeoffs between performance of these tasks and the calculation time
they take may have to be evaluated in setting this parameter.
Note:
A large PLC 0 with a small value of I8 can cause severe problems,
because PMAC will attempt to execute the PLC program every I8
cycle. This can starve background tasks, including
communications, background PLCs, and even updating of the
watchdog timer, for time, leading to erratic performance or possibly
even shutdown.