5: U
SER
C
OMMUNICATION
I
NSTRUCTIONS
5-4
FC6A S
ERIES
M
ICRO
S
MART
A
LL
-
IN
-O
NE
T
YPE
C
OMMUNICATION
M
ANUAL
FC9Y-B1730
Transmit Data
Transmit data is designated by source device S1 using constant values or data registers. BCC code can also be calculated
automatically and appended to the transmit data. One TXD instruction can transmit a maximum of 1,536 bytes of data.
S1 (Source 1)
Note:
Total byte count of the transmit data is shown in S1 of TXD instruction on the ladder diagram of WindLDR.
Designating Constant as S1
When a constant value is designated as source device S1, one-byte data is transmitted without conversion. The valid transmit data
value depends on the data bits selected in the Communication Parameters dialog box. These data bits are set in
Configuration
>
Comm. Ports
, followed by selecting
User Protocol
in Port 1 through Port 3
list box and clicking the
Configure
button. When 7
data bits are selected as default, 00h through 7Fh is transmitted. When 8 data bits are selected, 00h through FFh is transmitted.
Constant values are entered in character or hexadecimal notation into the source data.
Constant (Character)
Any character available on the computer keyboard can be entered. One character is counted as one byte.
Constant (Hexadecimal)
Use this option to enter the hexadecimal code of any ASCII character. ASCII control codes NUL (00h) through US (1Fh) can also be entered using
this option.
Example:
The following example shows two methods to enter 3-byte ASCII data “1” (31h), “2” (32h), “3” (33h).
(1) Constant (Character)
(2) Constant (Hexadecimal)
Transmit Data
Device
Conversion Type
Transmit Digits
(Bytes)
Repeat
BCC Calculation
Calculation
Start Position
Constant
(Character)
0-255
No conversion
1
—
—
—
Constant
(Hexadecimal)
Data Register
D0000-D7999
D10000-D55999
A: Binary to ASCII
B: BCD to ASCII
–: No conversion
1-4
1-5
1-2
1-99
—
—
BCC
—
A: Binary to ASCII
–: No conversion
1-2
—
X: XOR
A: ADD
C: Add-2comp
M: Modbus ASCII
M: Modbus RTU
1-15