Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual - Manual (Page 80)

Chapter 6
PLC-5/VME Processor
Communications Commands
6-11
Important: The PLC-5/VME processor ADDR, OFFSET, and TOTAL
TRANS fields work together when the total number of words to be read
requires multiple packets.
Message Format
OFFSET DST
00
PSN
00
SRC
00
PSN
00
CMD
0F
STS
00
TNS FNC
68H
Command Packet
LNH
Hi
LNH
Lo
DST
00
PSN
00
SRC
00
PSN
00
CMD
4FH
STS
Reply Packet
TNS
up to 244 bytes
Lo Hi
PLC-V5 SIZE
Lo Hi
a
06 FF FILE #
Lo
FF ELEM #
Lo
PLC-V5 ADDR
Hi Hi
ADDR
b
DATA at address + offset
TOTAL
TRANS
a — data-type ID code byte(s). If there is an error, this field indicates EXT STS extended status and no data is returned in field b.
b — DATA is returned starting at the PLC-5/VME ADDR plus OFFSET, low byte then high byte for each word. The PLC-5/VME
processor returns an array of the specified data type containing the number of elements specified by the SIZE byte field.
See section on Data Types.
Error Codes
Extended status codes are reported in the reply packet. The STS byte
contains 00H if no error, F0H when the PLC-5/VME processor detects an
error. If an error, the error code is indicated in the EXT STS byte
as follows:
STS EXT STS Description
00H – No error
F0H 03H Illegal address—specified too many address levels
06H Illegal address—file does not exist
07H Illegal address—beyond the end of the file
0BH Access denied—privilege violation
Refer to page D-3 for additional information on PCCC status codes.