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Byte
ID
D0
D1
D2
D3
X
TA
Opcode Mirrored
2.1.1.7.2
Access to Module Data
The user first writes the call parameters, and then the opcode and toggle flag.
Once the opcode or toggle flag have changed, the output data is interpreted as
complete function call by the RTC module so that the function can be
executed. The function response is stored in the input data.
After the function has been executed, the opcode and toggle flags are mirrored
by the RTC module. This way, the user knows that his request has been
processed and the result is in the input data.
The toggle flag is necessary so that two function calls using the same opcode
(even though different parameters may be used) can be performed one directly
after the other.
WAGO-I/O-SYSTEM 750
I/O-Modules
Function Response
7
6
5
2
2
2
S
0
0
0
Opcode (mirrored)
Response parameter byte 0
Response parameter byte 1
Response parameter byte 2
Response parameter byte 3
reserved (value is always 0 and is not evaluated)
Transmit-
Acknowledge
(toggle flag)
instruction code of
the function call
4
3
2
1
2
2
2
2
0
0
0
0
A function call is receipted with a changing.
A function call is receipted with a changing.
750-640 [RTC Module]
Process Image
0
2
TA
• 19
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