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Programming Actions and Conditions
S7-GRAPH for S7-300/400 Programming Sequential Control Systems
C79000-G7076-C526-01
7-25
7.10
Supervision Errors and Acknowledgment
Every step can be assigned a supervision condition. Only active steps are
monitored. S7-Graph recognizes whether or not the supervision conditions are
satisfied (in other words when a supervision error has occurred).
A supervision error entering the state (1) results in event "V1", a supervision error
leaving the state (2) results in the event "V0".
1
0
t
V1
V0
Disturbance
No disturbance
1
2
Disturbance: conditions in the supervision are satisfied
No disturbance: conditions in the supervision are not satisfied
Signaling and Acknowledgment - Requirements
The signaling and acknowledgment of a supervision error is only possible with the
following settings in the "Compile / Save" tab page of the "Block Settings" dialog
(menu command Options > Block Settings):
•
"Standard", “Maximum", or "Definable" is set in the “FB Parameters" box.
S7-Graph then signals a supervision error with the output parameter ERR_FLT.
•
“Acknowledge Errors" is set in the “Sequencer Properties" box.
This means that supervision errors occurring during operation must be
acknowledged with the input parameter ACK_EF.
Whether or not an error must be acknowledged can be set as "definable" not only
in the settings in the dialog box but alternatively also using the relevant parameter
(EN_ACKREQ) in the parameter set.
Handling Supervision Errors
Errors that must be acknowledged affect only the relevant sequencer paths, so that
the remaining sequencer can be processed while the sequencer path affected is
only processed again after the error is acknowledged.