Mitsubishi Electric MELSEC FX Series - Page 127

FX communication
FX
2N
-232IF 10
10-7
10
Note : ASCII/HEX conversion
When execution of the ASCII/HEX conversion is specified, the hexadecimal numeric data (0 to
F) inside the send buffers (BFMs #1001 to #1256) is converted into the ASCII code, then sent.
The received ASCII code is converted into hexadecimal numeric data (0 to F), then saved to
the receive buffers (BFMs #2001 to #2256).
At this time, the send/receive byte count indicates the number of hexadecimal data.
a ) Send format when hexadecimal data is converted into ASCII code
Example : When the send data “10AB
H
”, the header “STX” and the terminator “ETX” are
sent
b ) Receive format when ASCII code is converted into hexadecimal data
Example : When the receive data “10AB
H
”, the header “STX” and the terminator “ETX”
are received
6 ) b14 (send/receive buffer data length)
The data is treated as follows in accordance with the buffer data length.
• In the case of 16 bits (b14=0)
• In the case of 8 bits (b14=1)
b15
0 0 0 1 0 0 0 0 1 0 1 0 1 0 1 1
Send data buffer BFM #1001
b0
The send byte count is "4".
S
T
X
A B 1 0
E
T
X
02 H 41 H 42 H 31 H 30 H 03 H
1
0
A B
Converted into ASCII
code before send
BFM #0
b15
1
0 0 0 1 0 0 0 0 1 0 1 0 1 0 1 1
b0
0
A B
S
T
X
A B 1 0
E
T
X
02 H 41 H 42 H 31 H 30 H
03 H
The receive byte count is "2".
1 byte 1 byte
Receive data buffer
BFM #2001
S
T
X
BFM
#1001
lower
BFM
#1001
upper
BFM
#1002
lower
BFM
#1002
upper
E
T
X
Upper 8 bits Lower 8 bits
Send/receive buffer
16-bit data is divided into
upper 8 bits and lower 8 bits,
then sent and received.
Example of send buffers
S
T
X
BFM
#1001
lower
BFM
#1002
lower
BFM
#1003
lower
BFM
#1004
lower
E
T
X
Ignored Lower 8 bits
Send/receive buffer
Upper 8 bits are ignored, and
lower 8 bits only are sent and
received as valid data.
Example of send buffers