Rockwell Automation 1771-QA Stepper Positioning Assembly User Manual - Manual (Page 55)

3–33 Programming and Operation
Publication 1771-UM002A–EN–P – May 2000
Jog reverse and Jog forward MCW, bits 14 and 15
When either software jog command bit 14 or 15 is enabled in the
user program, the jog move will be executed if jog data had been
previously transferred. The software jog command can be
transferred to the stepper controller module with jog moveset data (1
move) or can be transferred by transferring only a moveset control
word with bit 14 or 15 set. When the software jog command is
transferred in the moveset control word alone, jog data (identified by
SMCW load jog bit 03 set for an axis) must already be stored in the
stepper controller module.
The stepper controller module ignores all but the first 10 words of
jog moveset data if the load jog command bit is set. If this bit is not
set, only the first four words of the moveset will be processed.
Override MCW, bit 17
An override moveset block of one to ten moves is required to
transfer an override command. When the override command and
data are received by the stepper controller module, the storage data
in the module will be cleared and the override data will become the
new working moveset. Refer to section titled “Moveset Block,”
Override bit 17. Any moveset data (unwanted) accompanying the
offset command will be processed by the stepper controller module.
Choose one of the methods for voiding unwanted data described in
Block Length, above.
Initialization Preset MS Preset, bit 17
All moveset data is ignored by the stepper controller module when it
receives an initialization preset command unless the load jog bit is
set in the first move block. The initialization preset cannot be
transferred after the move profile has begun.
Load jog SMCW, bit 03
Must be set to identify the moveset block as data. See Jog reverse
and Jog forward above.
Data Table Sizing Considerations
The data table files that are used to store and transfer data to and
from the stepper controller module should be considered with respect
to available data table space. Typically, the data table will contain
the following files:
•
1 or more moveset files per axis- four overhead words plus six
words per move, 64 words maximum.
•
1 jog file per axis - ten words to store jog data.