Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 111)

Message Packet Formats
Chapter 5
5-32
Download Request
A computer can use this command to inform the 1775-KA module that it
wants to do a download. If the 1775-KA module grants the download
privilege, the computer may begin issuing physical reads or writes. If a
different station already has the download privilege, the second station is
denied the privilege.
Reply Format: (EXT STS Byte 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
05
File Read
This is a read command, starting address of which is either a file symbol
or a block address. This starting address must point to a file of words.
The function code is 4.
TNS DST SRC CMD FNC
0F 04
PACKET
OFFSET TOTAL
TRANS PLC-3 LOGICAL ADDRESS
(2-51 Bytes) SIZE STS
TNS STS CMD
4F
SRC DST
TNS STS CMD
4F
SRC DST EXT
STS
DATA — Max. of 244 Bytes
or 122 Words
Command Packet:
Reply Format: (EXT STS Byte Is Optional)
B. Format When Reporting an Error
A. Format When Successful Execution