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7.
INITIAL SETTING OF TRANSMISSION CONTROL DATA TO
BUFFER MEMORY
MELSEC-A
7.3
Reading Transmission Error Data
This section explains the contents of the buffer memory area where the
ONIOFF status of the error LEDs are stored. It also shows how t o turn LEDS
which are lit OFF.
7 . 3 . 1
Reading the error LED display status
(1)
Error LED display status storage area
The ON/OFF status of the error LEDs are stored in address 101 of the
buffer memory (see below).
2 G N (LED No.16)
2-PIS (LED No.17)
4-CIN (LED No.20)
4-PIS (LED N0.21)
4-PRO
(LED
N0.22)
4-SIO (LED N0.23)
r
1: LED lit
I
error occurred
No-protocol send data length error
0: LED not lit
(Section
9.6
gives details.)
no error
(2) Program example to read the error LED display status storage area
This gives an example of a program using the sequence program [FROM]
to read the error LED display ONIOFF status stored in buffer memory
address 101H.
Program example to read the error LED display status storage area
(AJ71 C24 I10 addresses 80 to 9F)
K1
Read the contents of the error LED display
1 - 1
FROMP
I
H8
I
H I 0 1
I
,
b15 b14
to
b 8 b7
b 6
b5
b4
b 3
b2
b l
bO
...
This shows that the 2-PRO
1
status storage area t o address D O
D O
DO
0
(LED No.18) is ON. This means
O
I
O
1
O
1
O
I
I
O
1
O
1
an RS-232C protocol error has
occurred.
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