S7+ subscription-DPs and real subscriptions in PLC

[hbraun]

Hello,

I have some questions about S7+ subscriptions for which i could not find information in the help:

1) Is the number of S7+ subscriptions that are used for parameterization of the _addrress config somehow related to the number of subscriptions created in the plc which counts towards the system limit. For example in my project I have 6 different subscrptions which are used. But when I send -report dispatch to the dirver I get output that 41 subscriptions are active:

WCCOAs7plus3: Max Subscriptions : 750
WCCOAs7plus3: Max subscr. Attrs : 20000
WCCOAs7plus3: Max GetRequest size : 100
WCCOAs7plus3: Active Subscriptions : 41
WCCOAs7plus3: Symbolic available : 1
WCCOAs7plus3: Active Connection : 0
WCCOAs7plus3: Active Device : 0

Why are there 41 active subscriptions instead of the expected 6?

2) Can I use the same subscription for _addrresses with different PLCs?


Thank you and kind regards

[dhoegerl]

Hello,

1) the S7 PLC can only hold a maximum number of variables per subscription (in your case 100 as stated by the "Max. GetRequest size") and the S7+ driver manages the distribution of "configured subscriptions" to "active subscriptions on the PLC" automatically for the user. Otherwise you would have to configure own subscriptions for every 100 variables in your project. That is the reason for the reported 41 active subscriptions - where one subscription is dedicated to the PLC Operating-State (Run, Starting, Stop).

2) Yes, from the users' perspective subscriptions are configured as easy as pollgroups and can therefore also contain addresses of different PLC connections. The driver will create active subscriptions for each PLC connection automatically.

Best regards,
Daniel

[hbraun]

Thank you for the information, this makes my configuration much easier because I do not have to care about the different PLCs.