417
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 order in which data is written to memory depends on the value of digit 0
of C. Eight bytes of data 12345678... will be written in the following manner:
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 destination words (D to D+(N
÷2)–1) exceed the data area.
5-30-2 TRANSMIT – TXD(48)
Limitations S and S+(N÷2)–1 must be in the same data area.
DM 6144 to DM 6655 cannot be used for S or N.
N must be BCD from #0000 to #0256. (#0000 to #0061 in host link mode)
Description When the execution condition is OFF, TXD(48) is not executed. When the exe-
cution condition is ON, TXD(48) reads N bytes of data from words S to
S+(N
÷2)–1, converts it to ASCII, and outputs the data from the specified port.
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
MSB LSB
D12
D+1 3 4
D+2 5 6
D+3 7 8
Digit 0 = 0
MSB LSB
D21
D+1 4 3
D+2 6 5
D+3 8 7
Digit 0 = 1
S: First source word
IR, SR, AR, DM, EM, HR, TIM/CNT, LR
C: Control word
#
Ladder Symbols
Operand Data Areas
N: Number of bytes
IR, SR, AR, DM, EM, HR, TIM/CNT, LR, #
TXD(48)
S
C
N
@TXD(48)
S
C
N
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