Calculated Value Channel (Test Device) - Time Goes Backwards?

[jerzydziewierz]

Hi,

 

i have a "test" device of type "D to A" - into which i put values using variable.AddValue(x).

 

I do that in a loop in a sequence.

 

However, the historical plot of this variable appears totally screwed - upon closer inspection, it appears to me that the autogenerated time is wrong, and sometimes even goes backwards. Sometimes as far as 20 minutes . . . .

 

 

 

What do I do wrong?

 

it nearly appears as if the binary format of the time was different than expected (bits flipped in the memory), or that the time resolution in the auto-generated time in x.AddValue(y) is too low . . .?

 

[AzeoTech]

DAQFactory only autogenerates the time in addValue() if the value inside the () doesn't have time already.  So:

 

mychan.addValue(3)

 

will autogenerate time, but:

 

mychan.addValue(myOtherChan[0])

 

will not.  It will instead use the time of myOtherChan[0].

 

I'm guessing that you are doing some calculations using values with time associated and that's getting carried through.  Use insertTime() to fix this:

 

myChan.addValue(insertTime(myOtherChan[0], systime(), 0))

[jerzydziewierz]

Yes, that helped.

 

I was taking a dynamic maximum value over last 10 minutes of the other channel. I have read the documentation but what thrown me off is that in my calculation process, i was using private variables, not channels. Apparently channel time is preserved when copying to private value.