I am trying to calculate a cumulative flow. I kick of the calculation at 12:05 after other daily totals have been calculated. I read the cumulative total from the previous day:
CumQgYesterday :: TagVal('Cum_Qg', 't-12')
and add the new daily total:
CumQgToday :: cumQgYesterday + 'Qg'
I then output the second result back to Cum_Qg
The calculation works fine when I look at the Preview Results. However if I attempt to adjust the timestamp using the Advanced Options, I get the message 'Cannot override output timestamp if any output is used as an input within an analysis'. I can see that there could be potential problems overwriting the input that you are reading in an analysis. However, surely what I am doing here is safe as i am reading yesterdays value, and creating a new point. Is there something about the way analyses work that would make this risky? Does anybody know the reason behind this behaviour? Is there a way to override this and adjust the output timestamp?