Rockwell Automation 1771-DCM USER MANUAL 1771-DCM - Manual (Page 33)

Programming the 1771-DCM
Chapter 6
6Ć12
Example 2:
Suppose you want to transfer 64 words, and you have configured the
1771–DCM to simulate a block transfer module in Rack 2, First
Module Group = 0. Also suppose that the 1771–DCM is located in
the same chassis with the local processor, and that the 1771–DCM’s
actual location (RGS) is 131. In this example, you allocated data
blocks for block transfer as follows: (Refer to Figure 6.4 for
PLC–2/30, or Figure 6.5 for PLC–3 Programming)
Data Block Supervisory Processor Local Processor
Read 600 through 677 300 through 377
Write 500 through 577 200 through 277
Data transfers would occur as follows for PLC–2 family processors:
Supervisory Processor To Local Processor
BTW Instruction Writes Data to the
1771-DCM from Words 500 through
577
BTR Instruction Reads Data from the
1771-DCM into Words 300 through 377
500 Status Word (Zeroed)
501 First Data Word
502 Second Data Word
:
:
577 Last Data Word
300 Status Word (Inserted by DCM)
301 First Data Word
302 Second Data Word
:
:
377 Last Data Word
Local Processor To Supervisory Processor
BTW Instruction Writes Data to the
1771-DCM from Words 200 through
277
BTR Instruction Reads Data from the
1771-DCM into Words 600 through 677
200 Status Word (Zeroed)
201 First Data Word
202 Second Data Word
:
:
277 Last Data Word
600 Status Word (Inserted by DCM)
601 First Data Word
602 Second Data Word
:
:
677 Last Data Word