Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual - Manual (Page 95)

Chapter 6
PLC-5/VME Processor
Communications Commands
6-26
Use this command to upload segments of PLC-5/VME processor memory
after a successful upload-all-requests command. You can upload up to 244
bytes (122 words) per packet. Words are loaded low byte first. The first
byte and the number of bytes read must be an even number.
Your upload PLC-5/VME processor memory uses successive read bytes
physical commands for each of three memory segments. The memory
segments are defined by start and end pointers returned by the upload all
requests command. The first command starts at the physical address
defined by a memory segment pointer. You must increment the physical
address in successive commands. You increment the current physical
address over the previous physical address by the same number of bytes
(equal to the SIZE value) for each command until the segment is complete.
The packet size of the last command may be less.
See the “Header Bit/Byte Descriptions” section on page 6-4 for a
description of all bytes except the following:
SIZE—this is a 2-byte field (low byte first) that contains the number of
bytes to read (up to 244, even number only) with each read bytes
physical command.
Message Format
a DST
00
PSN
00
SRC
00
PSN
00
CMD
0F
STS
00
TNS FNC
17H
Command Packet
Reply Packet
SIZE
DATA (up to 244 bytes) DST
00
PSN
00
SRC
00
PSN
00
CMD
4FH
STS
00
TNS a
a – The physical address is a four-byte field (order of bytes is lowest to highest)
where the current packet starts to read (for example, 00 0A 00 00 for
physical address A00).
a – This byte will be the EXT STS extended status byte if there is an error.
Otherwise, the PLC-5/VME processor omits this byte.
Read Bytes Physical