Omron CS1G/H-CPUxxH Instructions Manual page 882

Serial Communications Instructions
• Start code: None or 00 to FF hex
• End code: None, CR+LF, or 00 to FF hex. If no end code is specified, the
number of bytes to received is set from 00 to FF hex (1 to 256 decimal; 00
is used to specify 256 bytes).
The Reception Completed Flag (A39206) will turn ON when the number of
bytes specified in the PLC Setup has been received. When the Reception
Completed Flag turns ON, the number of bytes in the Reception Counter
(A393) will have the same value and the number of receive bytes specified in
the PLC Setup. If more bytes are received than specified, the Reception Over-
flow Flag (A39207) will turn ON.
If an end code is specified in the PLC Setup, the Reception Completed Flag
(A39206) will turn ON when the end code is received or when 256 bytes of
data have been received. If more data is received after the Reception Com-
pleted Flag (A39206) turns ON, the Reception Overflow Flag (A39207) will
turn ON.
When RXD(235) is executed, data is stored in memory starting at D, the
Reception Completed Flag (A39206) will turn OFF (even if the Reception
Overflow Flag (A39207) is ON), and the Reception Counter (A393) will be
cleared to 0.
If the RS-232C Port Restart Bit (A52600) is turned ON, the Reception Com-
pleted Flag (A39206) will be turned OFF (even if the Reception Overflow Flag,
A39207, is ON), and the Reception Counter (A393) will be cleared to 0.
Data will be stored in memory in the order specified in C.
If start and end codes are specified in the PLC Setup, the number of bytes
specified for N will be ignored and the data received when RXD(235) is exe-
cuted from the start code to the end code will be stored starting at D.
If 0 is specified for N, the Reception Completed Flag (A39206) will be turned
OFF, the Reception Counter (A393) will be cleared to 0, and nothing will be
stored in memory.
If CS signal monitoring is specified in C, the status of the CS signal will be
stored in bit 15 of D.
If DR signal monitoring is specified in C, the status of the DR signal will be
stored in bit 15 of D.
If CS and DR signal monitoring is specified in C, the status of the CS signal
will be stored in bit 15 of D and the status of the DR signal will be stored in bit
14 of D.
Receive data will not be stored if CS or DR signal monitoring is specified.
If 1, 2, or 3 hex is specified for RS and ER signal control in C, RXD(235) will
be executed regardless of the status of the Receive Ready Flag (A39206).
An error will occur and the Error Flag will turn ON in the following cases.
• The no-protocol mode is not set for the port in the PLC Setup.
• The value of C is not within range.
• The value for N is not between 0000 and 0100 hex.
Further data cannot be received until data received with RXD(235) is read
out. Read out the data from when the Reception Completed Flag turns ON
and the next execution of RXD(235).
Section 3-24
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