Monitor WINCC - PLC connection

Hi all,

I want to run a VBA script in WINCC advanced only if a connection to a certain PLC is established. I thought of setting and resetting a bit on the incoming system events "140000 - Connection established" and "140001 - Connection disconnected" But I have 2 PLC's connected to the WINCC advanced, and the script is only alolowed to run if one of them is connected. I know the system event also shows me the connected PLC but is there a method to use this information to realise what i want?

Thanks in advance

Well, the way I understand it there are two parts to this, you need:

1. A way to determine whether each PLC is connected/disconnected. 
2. A Script which can interpret your tags and calls or doesn't call the script you want to run.

to 1.)
Create a tag in each PLC, datatype: word. Go to your HMI-project tree and open "Connections".
Klick on your first connection, then klick on "Area pointer" (2nd window).  
Activate "Coordination" and add your PLC tag for the first PLC.
The third bit of this tag is your lifebit for your first PLC.
Repeat for 2nd Connection & 2nd PLC.

This lifebit toggles constantly. If you use a counter: after a certain time limit you can look if you have the right value and accordingly set/reset your own boolean tag. (For example "PLC_1_connected 1=connected, 0=not connected", same for "PLC_2_connected".)

to 2.)
Call your interpreter script, when either of the tag values change. 
(Tag "PLC_1/2_connected > Properties > Events > Value change".)
Have your script analyse which state you are in:
PLC1, PLC2,action
0           0       none
0           1       none
1           0       run your VBA script
1           1       none

Here are some links with similar and other ideas that might help you:

• https://support.industry.siemens.com/cs/ww/en/view/35538370
• https://support.industry.siemens.com/cs/ww/en/view/42453077
• https://support.industry.siemens.com/cs/ww/en/view/98278878 
• https://support.industry.siemens.com/tf/ww/en/posts/communication-with-2-or-more-s7-plc/68534?page=0&pageSize=10
• https://support.industry.siemens.com/tf/ww/en/posts/how-to-check-connection-of-hmi-plc-in-runtime/120875/?page=0&pageSize=10
• https://support.industry.siemens.com/tf/ww/en/posts/lifebeat-monitoring-of-hmi-in-wincc/80851/?page=0&pageSize=10

... mostly about WinCC flexible, but should work similar enugh.