Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 123)

Message Packet Formats
Chapter 5
5-44
PLC-5 Commands
PLC-5 stations can execute the basic command set with the following
exceptions:
Set ENQs
Set NAKs
Set Timeouts
Set Variables
This section presents the message formats of the PLC-5 command and
reply messages. The table below lists the messages in the order they will
be discussed:
Message CMD FNC
Download All Request
Download Completed
Modify PLC-2 Compatibility File
Read Bytes Physical
Read-Modify-Write
Set Processor Mode
Typed Read
Typed Write
Upload All Request
Upload Completed
Write Bytes Physical
Word Range Read
Word Range Write 0F
0F
0F
0F
0F
0F
0F
0F
0F
0F
0F
0F
0F 50
52
5E
17
26
3A
68
67
53
55
18
01
00
Important: In the example formats that follow, CMD and FNC values
are expressed in hexadecimal notation. Other values are given in decimal
form.
Important: In addition to the message packet fields already described for
the basic command set, PLC-5 messages can also contain the following
fields:
1. PACKET OFFSET — Contains the word offset between the
DATA field of the current message packet and the DATA field of the
first packet in the transaction. This offset value appears only in
command messages for file transfers, where the complete transaction
might require more than one command or reply message packet.
Packet offset appears only in command messages for file transfers,
where the transaction might take more than one message packet to
complete. The value of PACKET OFFSET is zero for the first
packet in a transaction.