Signal Express 2010 start conditions - record only when 2 conditions are true simultaneously

[WabJeff]

ow do you use two start condtions for logging data?  Why does the first condition remain true after the first event even if it is now false.  Why do the conditions not reset in the start conditions "met?" column if the data is toggling between the true and false states.  I only want to record when both conditions are true at the same time, not if both conditions have occurred at some point in time.  Any suggestions?  Thanks.

[Sanjay_C.]

Hi WabJeff,

Unfortunately, you are running into limitations that you really can't get past in the SignalExpress environment. The start conditions are setup to function as latches --meaning once the condition is met, the value of the trigger is set to true, and doesn't change even if the source of the condition subsequently changes its value. As a potential alternative, you could add the signals which are responsible for the start condition to the log. This way, after the run, you can go back through the log and pull out the subset of data for which both start conditions are met. This strategy might not be possible depending on the source of the condition (I'm not sure you can 'log' software triggers), and might not be feasible depending on the size of the data set.

Since there is no way to modify the latch functionality of start conditions, the SignalExpress environment might not be suitable for your application -- you may have to use LabVIEW or LabWindows/CVI in order to get the simultaneous triggering functionality on data logging.