User`s manual

5.0 - Motion Programs
Page - 54
5.10 - Other programming features
5.10.1 - Rotary Motion Program Buffers:
PMAC has a limited memory space shared for motion programs, plcs, compensation tables and gathering buffers. The
rotary motion program buffers allows running motion programs larger than the available space in PMAC’s memory.
Communication routines provided by Delta Tau have the necessary code to implement this feature in a host computer.
5.10.2 - Internal Timebase, the feedrate override
Each coordinate system has its own "time base" that helps control the speed of interpolated moves in that coordinate system.
If Ix93 is set at default, this parameter could be changed by different means:
-
1000 where ,% << nn : Online or CMD command that runs all motion commands in “slow-motion”.
-
225100 where ,% ≤< nn : Online or CMD command that runs all motion commands proportionally faster.
-
0% : Online or CMD command that “freezes” all motions and timing in that C.S.
-
100% : Online or CMD command that restores the real-time reference (1 msec = 1 msec).
- M197 = I10 : Suggested M-variable for timebase change. Equal to I10 is 100%, equal to 0 is 0%.
The variable Ix94 controls the rate at which the timebase changes:
23
2
2
t
I10
Ix94
⋅
=
, where t is the slew rate time in msec.
5.10.3 - External Time-Base Control (Electronic Cams)
The time reference of each coordinate system could be changed from the default internal reference, controlled by the “%”
command and variables Mx97, to an external source (usually a frequency reference from a master encoder). A simple
change of the variable Ix93 allows switching between the internal timebase and an external source. In this fashion, motion
programs can be developed and tested running in real-time (internal timebase) and synchronized later to a master frequency
when proven to be functional and completed.
Master encoder
generates pulses as
distance is covered
(like a web of material
passing by)
Pulses of the master
are seeing by PMAC
as a number that
represent a frequency
The coordinate
system timebase is
“adjusted” every
servo cycle based on
the master frequency
Motion programs in
PMAC are
programmed in time,
TS+ TA+TM and
DELAY
The distances
programmed in
PMAC are covered in
the times specified,
TS and TA+TM
The only setup part of this feature is an entry in the conversion table that will also indicate a scale factor for the maximum
frequency that the master can possibly input to PMAC. This maximum frequency will represent 100% or real-time.
PMAC’s memory
Rotary buffer
Motion Program in
a Text File
Portion of the
program
Host reads the file
from the hard driv
e
Code is sent to
PMAC’s buffer
Distance of the slaved coordinate system depends
on the distance covered by the master