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

Page 147

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Binary Command Language

Appendix A

A-19

A success code returns when the number of data words returned equals the
number requested. For example:

STX

02

OSC

01

SIZ

06

RSP

00

02

04

DAT

03

0F

02

ETX

03

CHK

26

The data bytes store:

size byte (02 hex)
lower byte of the first data word (04 hex)
upper byte of the first data word (03 hex)
lower byte of the second data word (0F hex)
upper byte of the second data word (02 hex)

A size too big code returns if the number of words requested requires a
response block larger than 63 words. In this case, 63 words return.

An address invalid – end of section code returns when the number of
words requested extends beyond the end of this section. The data from the
specified address to the end of the section returns.

If the processor returns any other response code, no data follows.

Read I/O Word

Hex: 23

Parameters: Address of required word

Description: You must send the I/O address using the following format
(Figure A.2):

Figure A.2

I/O Address Format

0

0

0

0

0

Rack Number

I/O Group

Number

a) Output Word

1

0

0

0

0

Rack Number

I/O Group

Number

b) Input Word

12136

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