Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 1055

Serial Communications Instructions
Flags
Precautions
1016
The following diagram shows the order in which data is sent and the contents
of the send frame for various start and end code settings.
No Start or End Code
Data
Only Start Code
Data
ST
Only End Code
Data
Start and End Code
ST Data
CR+LF End Code
Data LF
Start and CR+LF End Code
Data
ST
Data received.
Serial port on Serial Communications Unit
Bytes
1
2
3
N
4
(256 bytes max.)
5
6
Name Label
Error Flag ER
RXDU(255) can be used only for a Serial Communications Unit's serial port
that has been set to no-protocol mode.
Number of bytes
(Specified in allocated
DM Setup Area)
Number of bytes
(Specified in allocated
DM Setup Area)
ED
Number of bytes up to ED:
256 max.
ED
Number of bytes between
ST and ED: 256 max.
CR
Number of bytes up to
CR+LF: 256 max.
CR LF
Number of bytes between
ST and CR+LF: 256 max.
Byte order
0: Most significant bytes first
Most signifi-
cant bytes
15
D
Storage order
D+1
D+2
Byte order
1: Least significant bytes first
Most signifi-
cant bytes
15
D
D+1
D+2
Operation
ON if all of the logical ports are being used or the Com-
munications Port Enabled Flag for the specified logical
port is OFF when the instruction is executed.
ON if the value of C is not within range.
ON if the value for N is not between 0000 and 0100 hex.
OFF in all other cases.
Section 3-24
Least signif-
icant bytes
8 7 0
1 2
3 4
5 6
Least signif-
icant bytes
8 7 0
2 1
4 3
6 5