11-17
11 Programming Devices and Communications
CJ2 CPU Unit Software User’s Manual
11-2 Serial Communications
11
11-2-1 Overview of Serial Communications
Additional Information
Host Link master functions can be performed by sending the CMND(490) instruction via the
Serial Gateway when using Serial Communications Units with unit version 1.2 or later.
No-protocol communications allow simple data transmissions, such as inputting bar code data and out-
putting printer data using communications port I/O instructions. The start and completion codes can be
set, and RS and CS signal control is also possible with no-protocol communications.
The following figure shows the usage of each communications port I/O instruction, based on the com-
munications port being used and the direction of the data transfer (sending or receiving).
*1 Set pin 5 of the DIP switch on the front panel of the CPU Unit to OFF, and set the serial communications mode
in the PLC Setup to no-protocol communications.
*2 No-protocol communications are supported for Serial Communications Units with unit version 1.2 or later only.
No-protocol Communications System
FINS
FINS
CMND(490)
FINS command sent
PLC (Host Link Master)
PLC (Host Link slave)
Serial
Gateway
Serial Communications
Board/Unit
Host Link
header
Host Link
terminator
RS-232C
SCU
TXD
RXD
TXDU/DTXDU
RXDU/DRXDU
CPU
Applicable port
USB port
No
RS-232C port
Ye s
*1
CPU Unit
Serial
Communications Unit
Ye s
*2
General-purpose
external device
General-purpose
external device
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