Metasys automatically subscribe CoV possible?
We are using Metasys version 220.127.116.1100 on a MS-NCE25xx controller.
We want to use CoV to reduce the network traffic. As of now, Metasys can auto-discover our devices and field-points, in-fact CoV works to a certain extent too. However after field-points are auto-discovered, Metasys doesn't appear to automatically subscribe to the CoV. We have to either click on the AI object or change the CoV increment value in Metasys for the CoV to start working.
The problem is that we could potentially tave several tens of such devices and consequently hundreds of field points. It will be close to impossible to click on each point to ensure that CoV starts working. Moreover, the polling updates seem to continue even after the CoV starts working.
So a couple of questions:
(1) Is there any way to subscribe to CoV automatically upon auto-discovery of field points?
(2) Is it normal that polling continues even after CoV is subscribed?
(3) Is it all right to set a long polling frequency, like 5 or 10 minutes to overcome the problem of point (2)?
Thanks in advance,
As far as I know, the Johnson stuff does support COV subscription service - that a third party device can request to send information based on when the object's value changes. Again what I was told, was this eliminates the need for the 3rd party device to poll the JCI stuff for the information. You can only get to this setup \ attributes from the All Items > Expert view.
Thanks for the response. I'm not sure if I understood your correctly. What we need is the JCI controller to subscribe to our CoV service. It's the JCI controller (Metasys) that polls for the object value periodically from our device. Instead it should subscribe to the CoV service and get notified by our device when the object's value changes.
This mechanism is actually working as I mentioned. It's just that by default, JCI starts in polling mode. Then when we click on an AI object, the CoV gets subscribed and it receives notification on increment. Simultaneously , polling continues too. We would like the CoV to be subscribed by default.
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