I am searching for a channel variable that can perform a delta on the 1st record in a log, and the most recent logged record in a log.

Is that possible? There is a channel variable for 2 successive log measurements values in. This is called (DF) Difference (current reading - previous reading.) This is category of Data Manipulation under channel variable types. I would like to do a Delta calculation of the log values thus far.

That is, the log is still running and I'd like to delta 1st record since log program started and the most recent one. But don't know if there is a way to define this in the program structure. Can anyone help?

Best regards,
Dean

Depending on how your personal logic engine (brain) works and the specific needs of your task you could pick from one or a combination of these.:

• Use the immediate schedule to perform a measurement when the program is loaded and stick the result in a CV for later comparison.

• Use logical operators to setup a structure so that the logic is only 'true' the first time around.

• Use ALARM of IF statements to achieve the same thing.

Turn a schedule on and off as required using alarms.

Craigus