Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 117)

Message Packet Formats
Chapter 5
5-38
The above are privileged commands. This means that only a computer
can execute them. Their primary purpose is for uploading and
downloading PLC-4 memory.
PLC-4 stations cannot initiate any type of command message.
In addition to the message packet fields already described for the basic
command set (see “Message Packets”), PLC-4 messages may also contain
a byte called PLC-4 SEL. This field specifies which controller in the
PLC-4 Microtrol loop is the ultimate destination of the command
message. The allowed values for this field are:
PLC-4 SEL Value Meaning
0
1
2
3
4
5
6
7 Selects Controller #1
Selects Controller #2
Selects Controller #3
Selects Controller #4
Selects Controller #5
Selects Controller #6
Selects Controller #7
Selects Controller #8
Allocate
This command causes the 1773-KA module to allocate PLC-4 access
privileges to the computer station that originated the allocate commands.
Once the computer has this access privilege, it can send any of the other
privileged commands to the selected PLC-4 controller. No other
computer can gain access privileges to the same PLC-4 controller until the
privileges of the first computer have been deallocated.
If the 1773-KA module loses power, all access privileges are deallocated.
Reply Format: (EXT STS Byte Is Optional)
B. Format When Reporting an Error
TNS STS CMD
4F
SRC DST
TNS STS CMD
4F
SRC DST EXT
STS
A. Format When Successful Execution
Command Format:
TNS STS CMD
0F
SRC DST FNC
07
PLC-4
SEL