I'm trying to trend some variables from a RX3i PLC running an OPC UA server, everything looks fine but if the variable value doesn't change OPC doesn't update and my trending software reads blank in between updated values so i end up with bunch of lines and triangls for discrete signals instead of the usual on off pulses.

Is there any way to force OPC to always update even if the value doesn't change??

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Thank you
The older OPC DA reported data when the data moved outside a noise band around the last reported point; data within the noise was not reported. I missed that webinar on the basics of OPC UA, but I'll assume OPC UA does the same thing as OPC DA.

Your explanation does not mention missing data points, so it sounds like OPC UA is doing its job - the server is reporting data at the time it changes enough to warrant reporting and the client is getting the data.

However, the manner in which the points that are displayed is not appropriate for binary data (excellent graphic that you included demonstrating the issue). I would venture to say that OPC UA is only responsible for transferring the data and that OPC UA is not responsible for how the data is displayed graphically. The display of the data is the role of the HMI software/firmware. That HMI software uses OPC UA to transfer data, but the software is doing a linear interpolation between each successive points assuming the at the data is non-linear.

I don't know how to fix that, but something to look for would be the tag's or data point's 'Properties'. Data with binary properties deserves to be graphically displayed as binary data, in the traditional square wave format, as opposed to the linear interpolation method for analog data. Is there means of defining the data's properties as binary data, rather than analog data? I can't imagine you're the first guy in 25 years of OPC useage who wants to see binary data in the conventional 'timing diagram' binary format and HMI software must have tackled that issue by now. Such a property function might be defined in the HMI as well as OPC.
Thank you David.

I attached an exported file from the trending software and as i told you too many points are just blank.

The other thing is it's recording the values over and over at the same time stamp!

The software is incredibly reliable (GE trender) an it's working perfect with MARKVIe . I think i'm missing something.