External Trigger Not Working (Board Hangs)

[potsaid]

We have been testing our X6-400M and have been having problems getting the external trigger to work.

If we configure for software trigger, the card acquires data. But, if we configure for external trigger, the hard hangs indefinitely and no data is written to disk.

We also have some questions about differences in specs between the data sheet and user manual and are hoping you can help us out with these. Attached is a pdf for reference. Could you tell us:

1. Slide 2 in the attached pdf shows a photo of our card and a diagram from the user manual. The connector ordering of the Trigger and Ext Clock are different comparing the user manual to the labels on the card. The figure shows a Rev A board and ours is a Rev B. Are the labels silkscreened on our Rev B card endplate correct? We believe so because the external clock seems to respond as labeled. We have connected based on the endplate labeling for these tests.

2. Slide 3 shows External Trigger specs from the Data Sheet and the User Manual. The specs from the User Manual state 0.2V-1.5V, but the specs from the Data Sheet state 0.1V-3.3Vp-p. We chose to test with a 1Vp-p square wave to be safe, but what is the correct input voltage range and how should we interpret the other spec here?

Slide 5 shows that the rising edge of our trigger at 100kHz rate is 5ns/V, which is < the 10ns/V requirement listed in the data sheet.

Slides 6-7 show that software trigger works.

Slides 8-10 show that external trigger causes the card to hang.

3. Slide 11 shows a Jan 27, 2012 response from the X6-400M Forums concerning external triggering problems associated with resistor R567. Since we received our X6-400M module before this date, is it likely that this resistor is the cause of our triggering problems?


Do our general software setup and electrical connections look correct?

Do you suggest that we attempt to swap R567 and test again? Also, what would be your recommended input voltage for a square wave 100kHz trigger input?

Thank you very much.

[bjackson]

I am testing this on a board we have here. Right now I am seeing the same problem that you are. We are looking in to what may be causing it, and I will get back to you about that soon. It may be a simple software problem.

Regarding the discrepancy about which input is which, the labels on the board front panel are correct. We will correct the manual to reflect that.

The 0.1 to 3.3V range in the manual is the one referring to the trigger, however, I do not believe that 0.1V is enough to trigger it. We should correct that as well. 1Vpp should be enough, but just in case you should try triggering with a higher voltage. The 0.2V to 1.5V range refers to the inputs, not the trigger or clock.

[bjackson]

So, it turns out that the problem is in the software. The simple fix is to change line 324 from:
Trig.ExternalTrigger(Settings.Tx.ExternalTrigger ? true : false);
to
Trig.ExternalTrigger(Settings.Tx.ExternalTrigger || Settings.Rx.ExternalTrigger ? true : false);

It was only checking the settings for the D/A external trigger and not the A/D external trigger. The only problem with this fix is that it will not allow for one direction to be externally triggered while the other direction is software triggered, but if that doesn't matter to you, then go ahead and make the change. We will probably release a better fix to this later this week.

Thanks,
Brian

[bjackson]

Sorry, I didn't specify: That change is to the ApplicationIo code.

[potsaid]

Brian,

Thanks for your help with this. We made the suggested changes to the software, recompiled, and tested again.

What we are seeing now is that the card seems to trigger on its own and at random times, even if the trigger input connection is held constant.

The first test we did was to set the Stream software settings for external triggering. We then tried to acquire data with no electrical connections to the X6-400M card. We were surprised to see that it acquired data because there was no electrical trigger connection.

We then put a 50 Ohm terminator on the trigger (sync) input in order to ensure there was no noise of a floating input. We also connected AD0 to a 100 kHz sine wave source.

The card acquires data and it seems to trigger at random times.

As you can see in the attached pdf file on slide 5, the 100kHz sine wave gets acquired in frames, but the trigger starting position seems random.

We actually expected the card not to trigger because the trigger input was held constant by the 50 Ohm terminator. We are curious if you are seeing the same thing on your card also.

Thanks again,

- Ben

[bjackson]

Now, this sounds more like the issue described in the previous forum post here:
http://www.innovative-dsp.com/forum/viewtopic.php?t=1932

If you have the ability you can make the change yourself or you can send it back here and we will repair it for you.

-Brian

[potsaid]

Brian,

Thanks. I bet you are right. It would be interesting to continue our external clocking experiments with the ability to gate the data stream with the trigger capability working.

If we want to send the card back for the resistor swap, should we include an RMA number?

Thanks again,

- Ben

[bjackson]

Yes, if you want us to swap it for you, contact Peg Todd at
Ptodd@innovative-dsp.com

You can put Attn to me, Brian Jackson if you would like and I could try to get it fixed quickly for you.