WinCC Flex -- Possible to get PLC status?

theNoob · May 28, 2008

Is there any way to get the current status of the PLC (stop, run, etc.) or the status of a connection between the PLC and the HMI through WinCC Flexible?

I'd like to be able to log errors to the HMI or show status changes on screen if the PLC transitions to STOP mode, or becomes disconnected from the HMI (cable break).

There must be handles for that data somewhere, because the HMI is smart enough to know whether it's connected or not. I looked through the help section, but can't seem to find much info.

- theNoob

Nick B · May 28, 2008

There are a few ways. I would look at the area-pointers tab under the connections of each PLC. Their is a "Coordination" Word which you can monitor.Nick

theNoob · May 28, 2008

It seems that the "coordination" area pointer writes the HMI status to a location of your choice inside the PLC. Unfortunately, if the PLC has experienced a sudden loss-of-power, or has been inadvertently placed in STOP mode, I don't think it's possible to trigger an event on the HMI to log that condition with this method.

For my application, the HMI displays vital real-time data to the user at a remote location. Therefore, it's more important for the HMI user to be able to tell that the PLC is still there and functioning, rather than the other way around.

Is there any way to make that happen w/ WinCC Flex? (I'm using a TP277 if that helps...)

tim2 · May 28, 2008

I've seen this done with a sign-of-life display on the HMI panel. just a small button that changes colors every couple of seconds based on communication with the HMI panel.

In the PLC toggle a bit every second or so and have the PLC read the status, green when high, grey when low, red if missing for some length of time.

theNoob · May 28, 2008

My problem is that I need to tell the user of the HMI what the status of the PLC is. Toggling a bit on the PLC isn't very helpful for this, because if a cable breaks, the bit will keep toggling on the PLC and the HMI will continue to churn away in some undefined state.

What I need is to be able use the software running on the HMI (perhaps VB) to poll the PLC in some way to see if it's still there. But there don't seem to be any system functions that let you get your hands on the connection status...

Bratt · May 28, 2008

Check out this thread

Bratt · May 28, 2008

Or this....

tim2 · May 28, 2008

theNoob said:
My problem is that I need to tell the user of the HMI what the status of the PLC is. Toggling a bit on the PLC isn't very helpful for this, because if a cable breaks, the bit will keep toggling on the PLC and the HMI will continue to churn away in some undefined state. panels.

The operator can tell the PLC is dead because the button you place on the HMI panel will no longer change color every second. I work with alot of Siemens programs that do it this way in the automative industry for both HMI panels and CNC panels.

theNoob · May 28, 2008

Thanks Bratt, this is definitely what I was looking for!

This is a feature that Siemens should think about providing in WinCC. Allowing configurable events based on System Alarms (like "Connection Lost", for example) might be pretty nice too. Just in case anyone from Siemens is lurking and reading...

theNoob · May 28, 2008

Tim2 -- I apologize, I see your logic now. I'll have to determine what the best solution is, but at least now I have options.

Thanks to all who responded!

Nick B · May 28, 2008

Noob,

You can still use the Coordination method. Grab Value in PLC and move back to HMI in other area.

Now you know:
1. Your connected
2. PLC is running (data will not be being moved via PLC running)

Not elegant but effective.

Nick

CharlesM · May 31, 2008

Just found this

I think its just what your looking for

How is the diagnostic data of the DP diagnostics block FB125 in WinCC flexible visualized?
Instructions:
Using the diagnostics block FB125 from the S7 project "DP_DIAxx" the individual Profibus users can be diagnosed in a Profibus subnet. You can download the diagnostics block or the S7 project under the following Entry ID 387257.

http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=29338956&caller=nl

JesperMP · Jun 1, 2008

That FB125 can be used to get diagnostics for DP slaves configured in a DP master.
It is very good for that purpose, have used it myself. There should be a newer version that supports Profinet as well as Profibus (new block called FB126 I think).
Unfortunately, it cannot be used to diagnose master-to-master connections. It cannot tell if a connection is lost to an HMI for example.

CharlesM · Jun 1, 2008

Unfortunately, it cannot be used to diagnose master-to-master connections. It cannot tell if a connection is lost to an HMI for example.

Seems to me if you did not get any status from any slaves then you would know the connection was lost. They have the status screens for WinCC Flexible in the example. This would give you the status on the screen just not in the plc.

JesperMP · Jun 1, 2008

Now that would be a very indirect way of knowing in the HMI that the connection to the PLC is lost, if it could work that way.
But it cannot. It is the PLC that does all the diagnostics, not the HMI.
In case the HMI-PLC connection is lost, then in the screen with the station diagnostics (with all the squares, one for each station number), then the HMI would simply remember the status from when the connection was OK, i.e. "all green". For numerical outputs there will appear "####" after a while, but that is also not a good way to "know" that the connection is lost.

WinCC Flex -- Possible to get PLC status?

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