Is it possible to log EWS Points/Values in the EBO?

[mike_meirovitz]

Hi,

Is it possible to log EWS Server Points/Values in the EBO? If yes, can you please explain how? I need the logged values be displayed in trends.

Thank you.

Mike

[ardak]

Hello,

Could you expand on what you are trying to do? 

[mike_meirovitz]

Hi,

Thank you for your answer. We have EWS Server that is an OPC Client. We know how to display EWS values in the EBO. The question is: how can we log these values (on change or every NN minutes) so the customer can view the history data of these values (in trends for example).

Thank you.

Mike  

[ardak · Accepted solution]

Hello,

This is not really a smartconnector topic but what you need to do is create a trend log in EBO and set the monitored value to whatever value you need to log. It is possible to monitor EWS values so you shouldn't have any issues there.

BR

Armend

[SteveGregory]

You can create change of value logs in EBO but they will try to read the value every 0.5 seconds to determine if the value has changed, so each log will actually create a subscription to EWS point. This may be an issue if you have a lot of points as the EWS server is limited to 10k subscriptions.

Alternatively, if you create EWS History items in the EWS server, EBO can host those logs and upload the data at set intervals which is more efficient. The downside is that the EWS History item logs the data every time the EWS item is updated. If you are only updating the EWS item when the value has changed then this is fine, although the update delta may still result in excessive logging. I don't know if there is way to update the EWS value on the server, without creating a log entry on the history item. 

Another alternative is to set up interval logs in EBO, but i don't know if they will create a subscription. You'd have to test. Ultimately, on a large site / interface, it pays to understand the mechanisms and limitations of each system.

[mike_meirovitz]

Hi Steve,

Thank you for your answer! Can you please explain how the EWS server can create History items? Where the history items are saved? SQL Server? Is it possible to display the data as trends in the EBO? 

Thank you.

Mike