419
Communications Instructions
Section 5-30
Control Word (C)
The value of the control word determines the port from which data will be read
and the order in which data will be written to memory.
The specified number of bytes will be read from S through S+(N
÷
2)–1 and
transmitted through the specified port.
When digit 0 of C is 0, the bytes of source data shown above will be transmit-
ted in this order: 12345678...
When digit 0 of C is 1, the bytes of source data shown above will be transmit-
ted in this order: 21436587...
Note
When start and end codes are specified the total data length should be 256
bytes max., including the start and end codes. (The maximum data length is
254 bytes when both a start code and end code are specified.)
Flags
ER:
A port on the Serial Communications Board is specified, but a Serial
Communications Board is not installed.
There is an error in the communications settings (PC Setup) or the op-
erand settings.
Indirectly addressed EM/DM word is non-existent.
(Content of
*
EM/
*
DM word is not BCD, or the EM/DM area boundary
has been exceeded.)
The source words (S to S+(N
÷
2)–1) exceed the data area.
5-30-3 CHANGE SERIAL PORT SETUP – STUP(––)
Byte order 0: Most significant bytes first
1: Least significant bytes first
Not used. (Set to 0.)
Serial port specifier (when bits 12 to 15 are 0.)
0: CPU Unit's built-in RS-232C port
1: Serial Communications Board port 1
2: Serial Communications Board port 2
Port 0: Port other than the peripheral port
1: Peripheral port
Digit number: 3 2 1 0
0
MSB LSB
S
1
2
S+1
3
4
S+2
5
6
S+3
7
8
N
:
Port specifier
IR 000, IR 001, IR 002, or IR 003
S
:
First source word
IR, SR, AR, DM, EM, HR, TIM/CNT, LR, #
Ladder Symbols
Operand Data Areas
STUP(
−−
)
N
S
000
@STUP(
−−
)
N
S
000
Third operand
:
Set to 000.
−−−
