974
Serial Communications Instructions
Section 3-24
Instructions
Communications frames
Function
TXD(236),
RXD(235),
TXDU(256),
and
RXDU(255)
Sends or receives data in one direction only.
A send delay can be set.
PMCR(260)
Up to 16 steps can be defined for sending
and receiving.
Steps can be changed and retry processing
performed based on responses.
Communications monitoring times can be
set.
Symbols can be read/written for the PLC.
Repeat symbols can be used.
Other.
Instructions
Mode
Communications ports
TXD(236)
and
RXD(235)
No-protocol
(custom)
TXDU(256)
and
RXDU(255)
No-protocol
(custom)
PMCR(260)
Protocol macro
Data
Data
Data
Data
Only End Code
Data
Data
Any of the following can be used.
No Start or End Code
Start and End Code
Only Start Code
CR+LF End Code
Start and CR+LF End Code
Header
Address
The following type of frames (messages) can be created
to meet the requirements of the external device.
Data
Error check Terminator
Communications steps
can be created.
I/O memory
Read/write
TXD(236)/
RXD(235)
RXD(235)
TXD(236)
TXD(236) and RXD(235)
use serial ports on the
CPU Unit or Serial
Communications Boards
(Ver. 1.2 or later).
Serial port in CPU Unit or Serial Communications Board
CPU Unit
TXDU/RXDU
RXD
TXD
Serial Port of Serial Communications Unit (Version 1.2 or later)
CPU Unit
Serial Communications unit
Serial Commu-
nications Board
Serial Communications Board (CS Series
only)
Receive
Send
Send
Receive
Serial Communications Unit
Serial Communications Unit
Summary of Contents for SYSMAC CS1D-CPU**
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Page 29: ...xxx...
Page 185: ...146 List of Instructions by Function Code Section 2 4...
Page 1389: ...1350 CJ series Instruction Execution Times and Number of Steps Section 4 2...
Page 1390: ...1351 Appendix A ASCII Code Table ASCII SP Four leftmost bits Four rightmost bits...
Page 1391: ...1352 ASCII Code Table Appendix A...