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RS-232C Serial Communications Section 7-2
7-2 RS-232C Serial Communications
This section provides a description and example of connection to an OMRON
Standard PLC. No-protocol communications are used for connection with an
OMRON Standard PLC.
7-2-1 Communications Specifications and Settings
With G9SP-series Safety Controllers with unit version 2.0 or later, you can use
the previous baud rate of 9,600 bps or you can use a new baud rate of
115,200 bps.
Baud Rate Setting
You can change the serial baud rate on the DIP switch on the G9SP-series
Safety Controller. (Refer to 2-1-1 Part Names and Indicators.)
The DIP switch setting is read only when the Controller’s power supply is
turned ON or the Controller is reset. You cannot change the baud rate while
the Controller is operating.
■ DIP Switch
Precautions for Correct Use
Always turn OFF the power supply to the G9SP-series Controller before you
change the setting on the DIP switch. The baud rate can be changed with this
DIP switch pin with unit version 2.0 or later.
Communications Specifications
If you use a baud rate of 115,200 bps, use a communications cable length
(i.e., a transmission distance) of 3 m or less.
Note The RS-232C standard defines a cable length of 15 m max. for a baud rate of
19,200 bps. The standard does not define a cable length for a baud rate of
115,200 bps. Therefore, you must check signal deterioration, peer specifica-
tions, and other factors, and sufficiently consider noise immunity.
7-2-2 Communications Format
Command Format (Standard PLC to G9SP-series Controller)
No. Name Meaning Default
SW3 Baud rate
(unit version 2.0 or
later)
OFF: 9,600 bps (default or unit version 1.@)
ON: 115,200 bps (unit version 2.0 or later)
OFF
Item Specification
Maximum transmission distance With a baud rate of 9,600 bps: 15 m
With a baud rate of 115,200 bps: 3 m
Baud rate 9,600 bps
115,200 bps
+0 Always 40 hex 1 byte
+1 Always 00 hex 1 byte
+2 Always 00 hex 1 byte
+3 Always 0F hex 1 byte
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