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Subscribing and reading large number of tags
10 Jul 2020 19:15 #8652
by support
Replied by support on topic Subscribing and reading large number of tags
In OPC general, subscriptions are preferred over periodic reads, so you should go with the subscriptions unless there is a reason not to.
From your experience, you can experience "slowness"
A) at browsing time,
during data retrieval (be it periodic reads, or subscriptions).
From the forum category (OPC Classic), there isn't much that can be done to speed up the browsing, if you are doing it effectively already (not browsing what does not have to be browsed). If it were OPC UA, at least with some servers, it would be possible to subscribe to address space change events, and avoid the repeated browsing 4 times a day.
As to the data retrieval, if you have any concrete numbers (measurements), post them here please, otherwise it is difficult to judge. And, the reason can be on the server side, the client side, or both. In addition, if you are currently doing the reads but want to use the subscriptions, it probably does not make much sense to care about the reads for now.
Best regards
From your experience, you can experience "slowness"
A) at browsing time,
during data retrieval (be it periodic reads, or subscriptions).From the forum category (OPC Classic), there isn't much that can be done to speed up the browsing, if you are doing it effectively already (not browsing what does not have to be browsed). If it were OPC UA, at least with some servers, it would be possible to subscribe to address space change events, and avoid the repeated browsing 4 times a day.
As to the data retrieval, if you have any concrete numbers (measurements), post them here please, otherwise it is difficult to judge. And, the reason can be on the server side, the client side, or both. In addition, if you are currently doing the reads but want to use the subscriptions, it probably does not make much sense to care about the reads for now.
Best regards
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