7 Programming FCs (Functions) and FBs for S7 Ethernet CPs
A-203
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
Case a: Sequence with older CP types
When the FC is called, the user program prepares the buffer for the received
data and instructs the CP to enter the received data there.
As soon as a data record has been entered fully and consistently in the receive
buffer, this is indicated by the parameter NDR = 1 in one of the next FC calls.
The status code in the output parameters NDR, ERROR, and STATUS is
updated in each block call and can be evaluated.
Accept / evaluate
received data “A”
User program
(CPU cycle)
Ethernet CP Communications Partner
Job completed without error
1)
No data available
yet
1)
AG_RECV
AG_RECV
AG_RECV
No data available
yet
1)
Job completed
without error
1)
AG_RECV
AG_RECV
Transfer
“A”
active over
Ethernet
Transfer
“B”
active over
Ethernet
Transfer
“C”
active over
Ethernet
Legend:
1)
Parameter transfer NDR, ERROR, STATUS
Time Time Time
Accept / evaluate
received data “B”
.
.
.
FC6 AG_RECV / FC60 AG_LRECV - continued
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