During measurements with a serial communication the timing of the measurement is not correct (delayed about 5%). The displayed time (graph) is reduced about 25 % what means during a measurement period of 24 h the curve shows only 18 h.
A couple of questions to better understand your scenario: -Are you using GRAPH or VIEW? -Are you getting your data from LabVIEW or are you acquiring from DIAdem? -Have you checked the raw time values? do they look correct? (All the way to 24 h)
the data acquisition via serial port doesn't work with the interrupt functionality but with polling. That means that DIAdem is waiting until your front end comes back with a value. So it is possible that there is an delay between the clock rate you set and the clock rate of the communication. But to verify this more exactly I need more detailed infos about the front end, the DAC scheme and the DIAdem you are working with.