Driver for Tektronix 420 produces 9.9E37 as measurement.

[SenorTito]

I am a student at VA Tech and have been using LabView 7 Express for the past 4 weeks to design a GUI for the Power Laboratory. I am having a problem with the "Read Measure" part of the driver for the Tektronix 420 Oscillscope. When I implemented it in a program it does not give back the right measurement unless the "Highlight Execution" button in the block diagram is switched on. Even when it is switched on, I am trying to read 4 different measurements and only 3 out of the 4 come out correctly. I am connected to the Scope through a GPIB connection.

[Brian_Powell]

Let me guess--you have a 30" monitor. Those are some mighty large diagrams you have there. You might consider creating subVIs to encapsulate your program a little better. Try to make each diagram relatively small and readable, and try to avoid the sequence structure.

But I digress...

I think the problem is that the instrument doesn't tolerate being sent multiple commands at the same time. You have four "Read Waveform" VIs running in parallel. The instrument can't process four commands to read at the same time.

I'm not real familiar with that instrument driver, but I think you just need to ensure that the four "Read Waveform" VIs don't run in parallel. For example, connect them each left to right with the error I/O terminals connected together. Th
is will ensure that one finishes before the next one starts.

Does this make sense?

Brian