Somebody at Seeq let me know about the new exponentialfilter() function that came out in R50, which does what I was asking about above. I started playing with it today, but am having some issues with it because tau has to be a scalar. In my process, tau changes with production rate, so this is an issue.
Is there a simple way of getting around this? I'm experimenting with the toscalars() function, but I'm actually getting errors saying it won't consume a Signal, although the help file appears to show toscalars being applied to signals. My thought was to create 1 minute capsules using the periods function, and doing something like this:
$minutes = periods(1min)
$tau_scalar = $tau.toscalars($minutes)
$signal.exponentialfilter($tau_scalar,1min)
Obviously, I'd love it if the function would accept signals for tau, but can anybody think of a way around it in the meantime?