I have 4 mobile panels 177 on a Profibus network, and somtimes a panel (not always the same) freezes (no manipulation is possible anymore).
In the software of the panel I have one tag that sees an integer variable in the plc that is raised with value one each scan cycle of the plc, this tag has an update time of 500 ms cyclic continuous.
This tag has an event on change of value that is transfers its own value to another tag.
This last tag has an update time of 500 ms cyclic continuous and the plc looks at this tag to see if the panel is connected (this is an alternative for the live bit of the panel, that I didn't wanted to use).
Could this be a reason for the freezing of the panel (no manipulations possible anymore)?
Or could there be other reasons?
As an alternative I tried to use the life bit of the coordination word from the area pointer of the panel.
This worked ok for one panel, but if I connect more then one panel I get a system message on the panel on startup : 'Interference on the bus'.
The area pointer for coordination for each panel in the cpu are in different databloks for each panel.
Why doesn't this work for more then one panel on the bus??????
In the software of the panel I have one tag that sees an integer variable in the plc that is raised with value one each scan cycle of the plc, this tag has an update time of 500 ms cyclic continuous.
This tag has an event on change of value that is transfers its own value to another tag.
This last tag has an update time of 500 ms cyclic continuous and the plc looks at this tag to see if the panel is connected (this is an alternative for the live bit of the panel, that I didn't wanted to use).
Could this be a reason for the freezing of the panel (no manipulations possible anymore)?
Or could there be other reasons?
As an alternative I tried to use the life bit of the coordination word from the area pointer of the panel.
This worked ok for one panel, but if I connect more then one panel I get a system message on the panel on startup : 'Interference on the bus'.
The area pointer for coordination for each panel in the cpu are in different databloks for each panel.
Why doesn't this work for more then one panel on the bus??????