NI 5112 Scope soft front panel setting problem

[wang]

Hi,

I tried to meausre a 5.1 voltage using SCOPE soft front panel. I could get 5.1 AC voltage from SCOPE soft front panel,

but it did not go back to 0 volt after 1 to 2 second in a horizontal line. Nornamlly, my 5,1V will go back to 0 volts

in my oscilloscope after 1 to 2 seconds because I am measureing a shock beep pulse waveform.

Can you tell why?

I am going to give you my setting.  I was trying Y-axis 2 volt/div, AC coupe, ch 0,  X-axis is 10 microsecond/div. normal mode.

Trigger: edge, rising, ch 0, trigger lever 2.5.

I am in a urgent. Coould you pls send me quickly

[Evan]

Wang,

The problem may be your trigger setting.  If you only have a single edge to trigger off of then the SFP will do one collection and then wait for the next edge, which it sounds like you don't get.

So above the green OK boolean does it say "TRIG?"?  If so the SFP is simply waiting for a trigger, in your case an edge.  I would suggest tyring other trigger types or increase the number of points you are acquiring so that you can see the entire signal.

[wang]

Dear Evan:

Thank you very much!

Now, I am sure this edge trigger in Soft Frint panel is tragger one signal at a time. I told you what I can get the entire signal.

Then problem is the entire signal would not go back to 0 volts and wait for someone press the buttons to generate the signal.

I tried using immediate type  and changed the number of point I am acquriing. It did not work. I also tried changed to 50ohm

impendance. It did not work too. Am I doing it right? May I ask the soft front panel functions like a same as an Tektronix

oscilloscpe. Because in oscilloscope. I can get my entire waveforem of AC 5.1V and then go back to 0 volts.

and wait for someone to press the button again to get the same entire waveform. Can this soft front panel function like

a real oscilloscpe. Can you answer to me directly? Is it is, what wrong with my step, how am I suppose to fix it?

I appreciate if you can reply to me quickly.

[Evan]

I'm sorry if I don't completely understand what the behavior is but if I understand you correctly, you have a signal that goes from 1 volt, peaks at 5.1, and then slowly drops to 1 volt again.  That entire signal takes 1 to 2 seconds.

I am not sure if the problem you are seeing is 1. you can never get the full signal in the SFP or 2. that the SFP does not wait for you to hit a button to try and acquire again.

If the question is number 1

 In the soft front panel when you set it to edge trigger you are able to capture the 5 Volt peak, however it never goes back down to 1 volt.

[Evan]

I'm sorry if I don't completely understand what the behavior is but if I understand you correctly, you have a signal that goes from 1 volt, peaks at 5.1, and then slowly drops to 1 volt again.  That entire signal takes 1 to 2 seconds.

I am not sure if the problem you are seeing is 1. You can never get the full signal in the SFP or 2. You get the signal ok but the SFP does not wait for you to hit a button to try and acquire again.

If the question is number 1

  If this is the issue it sounds like you are able to capture the 5 Volt peak, however it never goes back down to 1 volt.  You mentioned that you have the X-Axis set to 10 microseconds/ div.  Therefore the SFP is only acquiring an total of 100 microseconds, and if the reference is set to 50%, then you are only getting 50 microseconds of signal after the trigger, so you will not be able to acquire the 1-2 seconds it takes for your signal to drop.  I would suggest increasing the number of points and slowing down the Time/Division.  You should be able to change those settings a few times to actually get 2 seconds worth of signal.

2. If you want to simply hit a button and the SFP will acquire again then you need to change the mode to SGL.   Then you just need to hit the run or pause button and the SFP will acquire again.

Message Edited by Evan on 09-12-2005 10:03 AM