Omron SYSMAC CP Series Instruction & Reference Manual page 413

Start Code/End Code Settings and Receive Data
No Start or End Code
ST
ST
Start and CR+LF End Code
ST
Hint
• When RXD(235) is used to read data that was received at one of the Serial Option Board's ports , the
port's reception buffer is cleared after RXD(235) is executed. Consequently, RXD(235) can not be
executed repeatedly to read a block of data in parts.
Precautions
• RXD(235) can be used only for the CPU Unit's RS-232C port or the Serial Option Board port. In addi-
tion, the port must be set to no-protocol mode.
• Execute this instruction when the reception completion flag (RS-232C incorporated in the CPU unit:
A392.06, Serial Option Board: A392.14) is 1 (ON) to receive data (from the reception buffer).
• When data is received, the data must be read by an RXD instruction or the next data cannot be
received. When the reception completion flag turns ON, read the received data with an RXD instruc-
tion before the next reception.
• Specify the size of the receive data, not including the start code and end code, in N.
• If 0 is specified for N, the Reception Completed Flag and Reception Overflow Flag (note(a)) will be
turned OFF, the Reception Counter (note(b)) will be cleared to 0, and nothing will be stored in memory.
CP1E CPU Unit Instructions Reference Manual(W483)
1 2 3 4 5 6 0...
Only Start Code
1 2 3 4 5 6 0...
Only End Code
1 2 3 4 5 6 0... ED
Start and End Code
1 2 3 4 5 6 0... ED
CR+LF End Code
1 2 3 4 5 6 0... CR LF
1 2 3 4 5 6 0... CR
Received
CPU Unit's built-in RS-232C port
or Serial Option Board port
Bytes
1
2
3
4
Max: 256 bytes order.
5
6
Receive bytes: Specified
in the PC Setup
Receive bytes after ST:
Specified in the PC Setup
Receive bytes before
ED: 256 max.
Receive bytes between
ST and ED: 256 max.
Receive bytes before
CR+LF: 256 max.
LF
Receive bytes between
ST and CR+LF: 256 max.
When receiving the most significant
bytes first is specified (0):
Least signif-
Most signifi-
cant bytes icant bytes
N bytes
15 8 7
stored in the
1
D
specified
3
D+1
5
D+2
When receiving the least significant
bytes first is specified (1):
Most signifi-
cant bytes
15 8 7
1
D
D+1 3
D+2
5
2 Instructions
0
2
4
6
Least signif-
icant bytes
0
2
4
6
2
2-377