Rockwell Automation 1771-QA Stepper Positioning Assembly User Manual - Manual (Page 40)

3–18 Programming and Operation
Publication 1771-UM002A–EN–P – May 2000
Bit 02 Skip Bit.
The skip bit allows one or more moves of a moveset to be ignored
without reprogramming. When this bit is set, the corresponding
move block is skipped over. When operating in the continuous
mode, the move preceding the skipped move and the move following
the skipped move are blended automatically. Refer to section titled
“Application Considerations” to ensure that the blend is achievable
without a programming error. When operating in the independent
mode, the move following the skipped move begins as soon as the
one preceding the skipped move is done. Skip bits can be set
initially in the data table when move data is entered or they can be
set by user program logic. Skip bits must be set before the moveset
is transferred to the stepper controller module. Once the moveset is
transferred, additional skip bits cannot be set in that moveset.
Bit 03 Load Jog Bit.
This bit is set to identify the accompanying move block as jog data.
Bit 14 software jog reverse command or bit 15 software jog forward
of the moveset control word can be programmed to initiate the jog.
Jog data (with the load jog bit set) can be transferred to the stepper
controller module with the software jog forward or reverse command
(bit 15 or 14), or jog data can be transferred to the stepper controller
module in advance. See software jog forward and reverse command
bits 15 and 14 of the moveset control word described earlier in this
section. Refer to the section titled “Jog.”
An axis reset command will clear any previously transferred jog data
for that axis.
Bit 04-15 Must always be zero.
Bit 16, 17 Identification Bits.
Both bits must be set to identify each single move control word.
Otherwise, a programming error will occur.
Generally, bits of the single move control word are set by user
program logic. A command to the stepper controller module should
be cleared and the stepper controller module allowed sufficient time
to see the bit cleared before the next command is transferred. See
“Handshaking.”
Avoid sending multiple commands to the stepper controller module
at the same time. A programming error could result or the
data/command could be ignored.