Rockwell Automation 1771-KA2 Communication Adapter Module - Manual (Page 61)

Communication Zone Rungs
Chapter 5
5-9
The START bit is controlled by the program. This allows a command to
be initiated only when necessary. (Programming methods for START bit
control are given in chapter 7.)
Command Code
The second element in a command rung, the command code, identifies the
following:
Remote station number
Priority status of the command (priority or normal)
Type of command
NOTE: The command code uses the address of an EXAMINE ON
instruction, but does not examine or control any bit in the data table of the
local station processor.
Figure 5.5 shows the coding for this rung element.
Word Command Format
When the command code specifies a protected write, read, or unprotected
write command, use the format shown in Figure 5.6.
Figure 5.6
Word Command Format
027 07 032 10 020 00 AAA
G
BBB
G
CCC
G
AAA
Legend
BBB
CCC
Start
Bit Command
Code
Local Station Processor
Data Table Boundaries
Remote Station Processor
Data Table Address
Beginning word address of remote station processor for write/read operation
Beginning Word Address of local station processor for write/read operation
Ending Word Address at local station processor for write/read operation