4-3
Section
CPM2A/CPM2C Communications Functions
253
OFF while the data is being transmitted and will turn ON again when transmis-
sion is complete.
After the CPM2A/CPM2C has received data, the Receive Enable Flag turns ON.
When RXD(47) is executed, the data received will be written to the specified
words and the Reception Complete Flag will turn OFF.
Flag
Peripheral port
RS-232C port
Transmit Ready Flag
AR 0813
AR 0805
Reception Completed Flag
AR 0814
AR 0806
Note
The CPM2A/CPM2C starts and completes data reception at the following
points:
Reception Start:
Start code disabled:
Continually available for reception
Start code enabled:
After start code is received
Reception Complete:
When either the end code, the specified no. of bytes, or 256 bytes are received.
Application Procedure
Setting the Communications switch
Set the CPM2A CPU Unit’s communications switch or
the CPM2C CPU Unit’s DIP switch.
Connecting the cables
Make the RS-232C connection with the serial device.
Ladder program
The CPM2A’s communications are controlled by the communications switch on
the front of the CPU Unit and the CPM2C’s communications are controlled by
the DIP switch on the front of the CPU Unit.
CPM2A Communications Switch Setting
Turn OFF the Communications switch when using no-protocol communications.
No-protocol communications will not be possible if the communications switch is
ON.
Communications switch
Peripheral port
RS-232C port
Communications Switch
Setting