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I have a requirement that I thought would be SIMPLE, but can't get it to work. I have a 9205 card in a little 9174 cDAQ USB chassis. My *intended* behavior is to wait (block) at the DAQmx Trigger/Start Analog Edge on, say channel ai1, until I get a falling edge thru, say, -0.050V. So I have a little vi (that contains 2 parallel loops) that I want to sit & wait for the trigger to be satisifed. I'm doing "routine" voltage measurements in another AI loop on a different channel. I want this vi to run separately from my "routine" voltage measurements because I want the app to respond "instantly" to input voltage exceeding a limit to prevent expensive damage to load cells. I was afraid that if I used either Finite or Continuous sampling to "catch" an excessive voltage, I might miss it while I'm doing something else. Yes, yes, a cRIO real-time setup would be better for this, but this is a very cost-sensitive task... I just want to "Arm & Forget" this process until it gets triggered, whereupon it fires an event at me. SO... I'm also reading the same voltage on channel ai0 for regular-ole voltage measurements, and just jumpering them together. I did this because I read somewhere that you can't use the same channel for multiple DAQ tasks - I *thought* I would need to set up the tasks differently. {but now that think about it, the setups can be the same...}. I've set up the DAQmx task the same as shipping examples and lots of posts I've seen. I'm supplying a nice clean DC voltage to a 9205 card using a high quality HP variable power supply. Using NI-MAX, I've verified that my 9174 chassis & 9205 are working properly. THE PROBLEM - When I run it, the vi just sails right through to the end, with no error, and an empty data array out. No matter WHAT crazy voltage I give the "DAQmx Trigger.vi" (set up for Start Analog Edge), it never waits for the trigger to be satisfied, just breezes on through as if it weren't there. If I set the Sample Clock for "Finite Samples", the DAQmx Read fails with timeout - makes sense, since the trigger wasn't satisfied. What could I possibly be doing wrong with such a simple task??????? So my fundamental misunderstanding still vexes me - does the DAQmx Trigger vi not block and wait for the trigger condition to be satisfied, like the instructions state - "Configures the task to start acquiring or generating samples when an analog signal crosses the level you specify"? I stripped my requirement down to the bare essentials - see the 1st snippet, the 2nd is my actual vi. Any ideas, anybody?