Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 145)

Binary Command Language
Appendix A
A-17
Read Word Command
Hex: 12
Parameters: Address of required word
Description: The following example command block reads file 0, word 3
of the data table status section:
STX
02
ISC
05
SIZ
04
CMD
12 24
DAT
0D 03
ETX
03
CHK
54
The data bytes store:
address mask (24 hex)
address byte specifying status section 13 (0D hex)
address byte specifying word 3 (03 hex)
The processor responds with one of the following codes:
Response Codes
Hex Description
00 Success
04 Address unknown
06 Access not allowed
08 Address not complete
If a success code is returned, the next two bytes in the response block
contain the data stored at the requested address, with the lower byte
sent first:
STX
02
OSC
01
SIZ
03
RSP
00 05
DAT
08
ETX
03
CHK
16
The data bytes store the data word:
lower byte (05 hex)
upper byte (08 hex)
If any other code returns, no data follows.