Rockwell Automation 1771-QA Stepper Positioning Assembly User Manual - Manual (Page 116)

4–38 Example Programs
Publication 1771-UM002A–EN–P – May 2000
Rung 37
When the first profile moveset is sent to the stepper controller
module (rung 24), bit 16 of status word 201 will toggle. When bit
201/16 toggles, a false-to-true transition in rung 37 occurs and the
second profile moveset is transferred to the stepper controller
module and is stored in the buffer associated with that axis. The
second profile moveset (moves 11-20) for axis 1 is stored in file A
(500-577). The second moveset is blended automatically with the
first moveset to create a 20-move profile (continuous mode). Note
that bit 16 of the MCW (moveset bit) for the first profile moveset is
true and for the second moveset is false. Therefore, the profile for
axis 1 consists of a moveset 1 followed by a moveset 0.
Rungs 38 and 39
Same function as rung 37, but for axis 2 and axis 3.
Rung 40
Block transfer read rung. The module is located in rack 1, module
group 4, slot 0. The block length is set by the default value, 00. The
stepper controller module will automatically send the required status
words (four words for 1 axis, seven words for 2 axes and ten words
for 3 axes) depending on the highest numbered expander addresses
in the chassis. Since the stepper controller module will only send
back a maximum of ten status words, the remaining words 212-277
can be used for other purposes.
Rung 41
This rung contains a file-to-file move instruction which buffers status
data from the block transfer read file (200-211). Each time the read
block transfer done bit (114/07) is true, the contents of file A
(200-211) will be sent to file R (150-161). The done bit will be set
only after the transfer and received data have been validated by the
PC processor.
Rung 42
The rung contains a block transfer write instruction which sends
commands, jog data and profile data to the controller module. The
block length is set to 64 words by the default value 00. The block
transfer write file need not be buffered since the buffering is done
internally by the controller module.
Rung 43 and 44
Block transfer time-out rungs. if a block transfer is not completed
within 3 seconds, output 011/16 will be latched on. This output can
be used to energize a warning device.