Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 197)

Chapter 8
8Ć36
controller turns on the ready bits (45102 and 45502) in the status block,
thus inhibiting rung 1.
Rung 2
If both axes are ready (bits 45102 and 45502 both on), this rung gets the
address pointer in the second word of the status block (0450) and puts it in
the file-address word (0141) for the write-block-transfer instruction. The
address pointer in the status block contains the address for the parameter,
command, or a moveset block, as requested by the 1771-M3 controller.
Because of the action of this rung, the block of data requested by the
1771-M3 controller is written to the 1771-M3 controller when the
write-block-transfer instruction executes.
Rung 3
Rung 3 reads the status block from the 1771-M3 controller. The data
address (0040) is located in the timer/counter accumulated area of the data
table. The module location address (301) indicates that the 1771-M3
controller is in rack 3, module group 0, and the right slot of the module
group. Block length (00) is the default length. This allows the 1771-M3
controller to control the number of words transferred. During a read
operation, data loads into consecutive words starting with the designated
address (0447).
Rung 4
Rung 4 writes the parameter, command, or moveset block to the 1771-M3
controller module, as requested by the 1771-M3 controller via the status
block. The data address (0041) is in the timer/counter accumulated area
of the data table. Module address (301) is explained in the rung 3
description. The block length (00) is the default length. This allows the
1771-M3 controller to control the number of words transferred according
to the block it requests.
During a write operation, data transfers from consecutive data table words
starting with the first word of the parameter, command, or moveset block.
These blocks have starting addresses 0200, 0400, and 0500, respectively.
Other moveset blocks start at addresses 0600 and 0700.
Rung 5
Rung 5 transfers the third and fourth words of the status block to digital
outputs in module groups 0 and 1 of rack 2. We use these outputs to
display the position, following error, and diagnostic codes for axis 1.
Rung 6
Rung 6 transfers the seventh and eighth words of the status block to