Author Topic: Using Trig Out  (Read 3258 times)

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Offline echen1024

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Using Trig Out
« on: December 01, 2013, 06:54:41 am »
Well, I received my new DS1000Z, and would like to test the wfm/s. I have connected trig out to CH4 with a BNC, and all I am getting is a really slow )<0.1Hz) square wave, independent of timebase or mem depth.Can anyone help>
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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Online Zbig

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Re: Using Trig Out
« Reply #1 on: December 01, 2013, 07:57:38 am »
Check your Trigger Holdoff setting.

EDIT:
< 0.1 Hz, you say... Well, that's gotta be something else then as I don't think you can hold the trigger off for 10 seconds.
« Last Edit: December 01, 2013, 08:04:35 am by Zbig »
 

Offline echen1024

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Re: Using Trig Out
« Reply #2 on: December 01, 2013, 08:01:24 am »
It's at min (16ns) I tried max as well.
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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Online Zbig

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Re: Using Trig Out
« Reply #3 on: December 01, 2013, 08:09:53 am »
Are you sure the output is set to Trig Out and not the Pass/Fail function?
 

alm

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Re: Using Trig Out
« Reply #4 on: December 01, 2013, 08:10:44 am »
Is it actually triggering on something? What's the frequency of this trigger signal? If it's in auto mode, then I would expect a much slower update rate.
 

Offline marmad

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Re: Using Trig Out
« Reply #5 on: December 01, 2013, 08:42:48 am »
Is it actually triggering on something? What's the frequency of this trigger signal? If it's in auto mode, then I would expect a much slower update rate.

+1 to alm's question - are you sending the DSO a 1MHz sine (or something in that neighborhood) on another channel to trigger waveform captures?

BTW, using CH4 to measure will work - but it will give you the wfrm/s for two channels ON (as opposed to a single channel - the fastest possible rate) since the DSO has to update both the triggered channel and CH4. A better alternative is a frequency counter or another DSO if you want to know the single channel rate.
« Last Edit: December 02, 2013, 01:05:53 am by marmad »
 

Offline eV1Te

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Re: Using Trig Out
« Reply #6 on: December 01, 2013, 10:49:51 am »
My guess is also that you have to trigger on another signal, you can't trigger on the trigger output signal, since that is only generated when you actually trigger on something.

One other aspect I am not so happy with regarding the "Trigger Out" port:
It is NOT possible to use the "Trigger Out" together with the built in arb. signal generator. This seems like something they could implement easily, since it is very useful to have a trigger output on a signal generator (especially if you are generating waveforms that might cause incorrect triggering i.e. multiple pulses etc.)

Does the Agilent scope have trigger output on its signal generator?
 

Offline echen1024

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Re: Using Trig Out
« Reply #7 on: December 01, 2013, 10:54:58 am »
I am using normal trigger to trigger on a 50MHz sine wave from a crystal at auto mem depth.
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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Offline marmad

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Re: Using Trig Out
« Reply #8 on: December 01, 2013, 11:16:09 am »
I am using normal trigger to trigger on a 50MHz sine wave from a crystal at auto mem depth.
Can you post a screen capture of what the two traces look like on your DSO?

Here is my DS2000 with a 1MHz sine wave input to CH1 - and the Trig Out connected to CH2 and the wfrm/s showing on the counter.

« Last Edit: December 01, 2013, 11:20:53 am by marmad »
 

Offline eV1Te

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Re: Using Trig Out
« Reply #9 on: December 01, 2013, 11:16:51 am »
I am using normal trigger to trigger on a 50MHz sine wave from a crystal at auto mem depth.

Is it even possible to measure trigger frequency on the same scope as you are measuring on? I mean you will only get one pulse per waveformupdate, you will never see a square wave with several pulses since that would imply that it would trigger several times per waveform...

I think you need a second scope, or a frequency counter to measure it accurately.
 

Offline marmad

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Re: Using Trig Out
« Reply #10 on: December 01, 2013, 11:18:32 am »
Is it even possible to measure trigger frequency on the same scope as you are measuring on? I mean you will only get one pulse per waveformupdate, you will never see a square wave with several pulses since that would imply that it would trigger several times per waveform...

I think you need a second scope, or a frequency counter to measure it accurately.

This was answered just a few posts above: https://www.eevblog.com/forum/testgear/using-trig-out/msg340002/#msg340002
 

Offline eV1Te

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Re: Using Trig Out
« Reply #11 on: December 01, 2013, 12:17:21 pm »
Is it even possible to measure trigger frequency on the same scope as you are measuring on? I mean you will only get one pulse per waveformupdate, you will never see a square wave with several pulses since that would imply that it would trigger several times per waveform...

I think you need a second scope, or a frequency counter to measure it accurately.

This was answered just a few posts above: https://www.eevblog.com/forum/testgear/using-trig-out/msg340002/#msg340002

I wasn't aware that the DS1000Z had the same hardware frequency counter as the DS2000, I thought that it maybe calculated the frequency from the acquired square wave in software (which would not work). But I was wrong, it does have the same frequency counter as the DS2000 series and it does indeed work to measure trig out on my DS1000Z (I just had to try it now  ;)), i get maximum 15 kHz with 2 channels enabled (10 ns time base and Dots mode).
 


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