The Historical Data Log provided conditional logging(Start/Stop Trigger). It is very useful for a batch control that would avoid to log a lot of garbage.
So, are there any way to do this function with the Historical SuperTrend logging? Do Opto 22 plan to develop this function?
Thanks,
Edmund
@Edmund - I have experienced a similar/the same issue. I want to collect a specific data set using conditional logging with the HistoricDataLog and I want to see it plotted on the HMI, like in a SuperTrends plot. I do not, however, want all the extraneous data that is collected while doing a SuperTrends Log. What I have done to remedy this is to set up a conditional historical data log that collects only the data I want. I also have that same data plotted in real time on a window using a SuperTrends plot that does not save files.
Another idea Iāve been considering is - to collect the data I want using a conditional historic data log. Save the historic datalog file to the flash memory on the controller. Parse the file to obtain just the information I want. Move that data to a table. And then plot the table in an XY plot. Again, this is just an idea. I have not actually ventured into trying it out and seeing if it works.
But yes I too feel that it will be a helpful feature to add - the conditional logging functionality in a SuperTrend Log.
@Edmund In short no.
Reason being is that the super trend x-axis is timeā¦ Its a big tricky - even for Opto - to stop and start time.
The historic data is time stamped when it is collected, so we can have a start / stop trigger for that.
Best you could do is to plot on the super trend a variable from the strategy tree, when you want to plot data, move the value you want to plot into that variable, when you want to stop plotting data, move zero into that variable.
Then, you would see the trend pen drop and āclean upā the trend line while the process was off, but time will still keep ticking by and move the graph to the left, ready for the moment the time is right for the process to start again.
Also, by moving zero (or what ever non-process related value you wanted) to the trend pen, you could then easily filter that out of the super trend file if you need to do that.
It makes perfect sense to me now why we canāt just use a start/stop trigger for a live trend since it implies āstoppingā and āstartingā time, doh! Thank you for the suggestion to move the variable we want to plot to a different variable that we can just make zero when we donāt want to see it plotted.
My question is the Historical SuperTrend not the Real-Time SuperTrend.
Your suggestion would still log a lot of āZeroā.
I donāt understand the SuperTrend can be started and stopped by the Windowās state, why it canāt be done by a Variable of the Strategy.
@Edmund - Just curious, why do you want to use a historical supertrend for this instead of a historic data log? My understanding is that you just want historical supertrend without a real time plot of data, correct?
We need both of the real time and historical trend. The historical data log donāt provide to plot the curve from a data log file.
Oh, ok. I understand now.