Our DCS and PI system get time from difference source. I'd like to set up an Analysis that will trigger a notification when the times drift apart too much. DCS time is passed to PI via OPC tag in the form of string. I can use ParseTime('DCS Time String') to convert the DCS time stamp into time PI time, and use ParseTime ("*") to get the PI system time. I can also subtract the two times and get the difference. The result is in the form of -00:00:04.466336. I cannot seem to map the result to an attribute though doesn't matter what type of Value Type I choose for the attribute. It always say "Cannot convert '-00:00:04.466336' to DateTime" or whichever type I choose.
It also seems that I cannot use Abs around the time subtraction.