Tektronix DO4104 Scope Trigger issue

[bobholmgren]

I'm having the same issue the fellow in this thread was having: http://forums.ni.com/t5/LabVIEW/Tek-7104-Triggering-problem/m-p/948510

I would like the scope to wait for the trigger, such that, if I set the trigger voltage at 4 volts, then feed it a square wave that never reaches 4 volts, it never trigger and will simply wait for the timeout that I fed it in the "Maximum Time" field of the example VI. The description for the Read (Single Waveform) VI states "A timeout error can occur when the trigger level is out of the range of the waveform" when referring to the timeout that I input, but I put 10 seconds, and it definitely doesn't wait even one second.

Any ideas?

I'm in Labview 7.1

Thank you,

-Jason 

[bobholmgren]

Sorry, its the Tektronix DPO4104

And this is the code i'm using

http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=1C445FA0619D698AE0440003BA7CCD...

[John_M.]

Hi Jason,

I just wanted to clarify with you that I am understanding correctly. Let's assume you specify a trigger voltage of 4 volts and a read timeout of 10 seconds. Then if you input a square wave with an amplitude of 3 volts, the read does not wait for 10s? Do you get a timeout error after some amount of time? Or what happens after that amount of time?

Also, I took a look at the driver you mentioned. Are you using the "tkdpo4k Edge Triggered Acquisition Waveform Example"? If not, which one?

Also, what exactly is the value that you have specified for the Maximum Time? The value is in miliseconds. So a value of 10,000 should correspond to 10 seconds. Lastly, what have you set for Vertical Coupling?

Best Regards,

John M

[bobholmgren]

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@John_M. wrote:

Hi Jason,

I just wanted to clarify with you that I am understanding correctly. Let's assume you specify a trigger voltage of 4 volts and a read timeout of 10 seconds. Then if you input a square wave with an amplitude of 3 volts, the read does not wait for 10s? Do you get a timeout error after some amount of time? Or what happens after that amount of time?

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Yes, that is exactly the case. If I give it a 3v square wave and a trigger voltage that it will never reach, and a read timeout of 10 seconds, it doesn't wait and just finishes running and show a 0 waveform when it should wait 10 seconds until there's a trigger, and then output the data. I just went to the lab to test this again to make sure, and that was the exact behavior.

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@John_M. wrote:

 

Also, I took a look at the driver you mentioned. Are you using the "tkdpo4k Edge Triggered Acquisition Waveform Example"? If not, which one?

Also, what exactly is the value that you have specified for the Maximum Time? The value is in miliseconds. So a value of 10,000 should correspond to 10 seconds. Lastly, what have you set for Vertical Coupling?

Best Regards,

John M

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Yes, I am running the "tkdpo4k Edge Triggered Acquisition Waveform Example.vi."

 For maximum time I increased it to 20000 from 10000, same exact program behavior. For vertical coupling, I have it set to DC.

[Dennis_Knutson]

I don't have a scope to play with but I can tell you that the read VI checks the status byte register by doing a *STB and reading bit 5. If that is true, the operation proceeds. Verify that is the correct bit. You might want to set a breakpoint at the Wait for Operation Complete subVI, step into it and see what is read.