OPC DA Collector - Data Transform - NoOutput
Hi,
I have an instrument that sends negative values when not in function (ex: -9999). I want to filter these values. The following OPC DA Data Transformation works fine: (x<0?(0):x) but instead of sending 0, I'd like to send nothing (NoOutput).
I do not see how to do that but the documentation seems to indicate that this is possible
Thanks
8 replies
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Hi eric. tremblay ,
The only time we do not send a value is if deadbanding is being used, but that would not help in this scenario as the value would exceed that deadband limit.
The calc server has this capability if you wanted to create a calc to filter out the negative values.
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Thanks Steve,
I knew the Calc Server can do that but I have many, many tags like this. That would almost double the number of tags.
What about the OPC UA collector? I saw that it can transform values as well as Qualities? I am planining to replace my OPC DA collectors by OPC UA collectors.
Thanks again
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eric. tremblay
We can't prevent the value from being sent but we can override the quality so that the value could be marked with a 'NoData' quality. This would at least prevent the value from being used in calculations or aggregation and also from being drawn on a trend.
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Could it be used to filter Bad Quality values, and mark them as 'NoData'? -
I'm not sure it would be any different as 'NoData' quality values are treated virtually the same as Bad quality values.
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, the thing is that when I receive a Bad Quality value on an OPC DA tag that changes only once a week, all the calculations that include this tag writes a Bad Quality value also, and is not displayed on Axiom. I am using OPC DA.
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, the OPC DA logger does not support quality overrides like the OPC UA Collector. Aside from that, a calculation would still output NoData qualities and not be displayed in Axiom, the same as a Bad quality.
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Exactly what I need !
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