Hello,
Sorry for the delayed response. You are right, I'm troubleshooting the case when server takes long time to respond with basic polling approach.
Actually, I'm awaiting feedback from Siemens OPC support. I will let you know if that advanced configuration is still relevant

Best regards

Thank you for explanation. I understand - it makes sense. The fact is, the approach used was largely OK with advanced polling, but is not ideal when basic polling is used plus the server takes long to respond, which is your case.

For design reasons we cannot put the additional into objects like DAGroupParameters which are given to every subscription. If we are going to implement it, it would be something like an additional factor (multiplier) in the structure of EasyDAClient parameters - e.g. you would be able to say "call SubscriptionPolledRefresh 2.5 times slower than the update rate (the requested sampling rate)".

This can be done, but only to a new version (API change). Unfortunately, we have scheduled a longer "pause" in version releases; do not expect a new version sooner than in September, probably. Let me know what your position on this is.

Best regards

Hello,

Thank you for your information.
I'm using Basic poll refresh approach.
I need to specify 2 sec for RequestedSamplingRate but call SubscriptionPolledRefresh each 5 sec.
It would be nice to have possibility to specify SubscriptionPingRate also. That is, set SubscriptionPingRate being 2 times longer than the update rate.

Best regards

Hello,

I do not write understand your question, because it postulates an assumption that is not true. The Subscription PolledRefresh is normally called at a rate different from a value of SubscriptionPingRate.

The computations are more complicated and there are conditions under which the behavior will be different, but normally, the SubscriptionPingRate end up being 10 times longer than the update rate you specify for the items in the subscription.

With basic polled refresh, the rate at which QuickOPC will then call SubscriptionPolledRefresh will also be the update rate of the items in the subscription.,

With advanced polled refresh then, the actual rate at which QuickOPC will call SubscriptionPolledRefresh depends on the responses of the server. The time between subsequent SubscriptionPolledRefresh may fluctuate between update rate of the subscription (if there are changes immediately available) and the SubscriptionPingRate (in case there are no changes in values). In this case, if there are no changes in values for extended period of time, it can truly happen that the rate of SubscriptionPolledRefresh calls will be roughly the same as SubscriptionPingRate.

To me this is all the way it is supposed to work, and I do not see an issue with it. I need to know what is the actual problem you are trying to solve.DO not forget to tell whether you are using Basic or Advanced poll refresh.

Best regards

Hello,

Is it possible to set "RequestedSamplingRate" , "SubscriptionPingRate" attributes of a Subscribe request and call SubscriptionPolledRefresh at a rate different from a value of "SubscriptionPingRate"?
e.g RequestedSamplingRate = 2000 ; SubscriptionPingRate = 10000; call SubscriptionPolledRefresh each 5 sec

Regards