strange event names of triggers on Actiview

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sofia doly
Posts: 3
Joined: Mon Mar 15, 2021 5:14 pm

strange event names of triggers on Actiview

Post by sofia doly »

Dear Coen,

I am sending triggers from e-prime by Chronos in the stimulus onset, using attribution (triggers), which I numbered according to different stimulus. (1,2,3,4)I am using two task events, one with 0 ms delay send the number of assigned triggers, second 10 ms later from the onset sends 0. This works perfectly in one computer.
However in another computer, when I start the experiment, the triggers numbers are all different like 134,170 or else some of them missing.
I dont understand what would be reason to cause this difference?

Could you please help me
Best,
Sofia
Last edited by sofia doly on Mon Mar 15, 2021 11:47 pm, edited 1 time in total.

Coen
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Re: strange event names of triggers on Actiview

Post by Coen »

Inspect in "analog" trigger display mode to see which trigger lines are faulty.

Best regards, Coen

sofia doly
Posts: 3
Joined: Mon Mar 15, 2021 5:14 pm

Re: strange event names of triggers on Actiview

Post by sofia doly »

Thank you so much for your quick reply. I really appreciate the support.

For instance, triggers are named 1,2,3,4, and 10ms later I send 0. Normally, in one computer, in the analog mode, I see 1 below 0, 2 below 0, etc... Like it supposes to be.

But in another computer, stimulus (1,2,3) have been seen as 131 below 130 (all same) and stimuli (4), is something like 134 below 130
(I am not sure if this description comes across correctly, I can have a screenshot if you want). So the first 3 stimuli send the same event names (but not the ones I assigned), 4th is different.

I don't understand how the same eprime experiment, can send different event names on different computers. It should be something about the computer right?
or is it possible that it is due to the receiver box or cables?

Kindly,
Sofia

Coen
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Re: strange event names of triggers on Actiview

Post by Coen »

In analog trigger display mode, you see 16 colored dots/bars, indicating the separate trigger lines (bits). It will probably show that there is something wrong with bit 8 (grey, 2^7 = 128). You did not follow my recommendation to inspect the bits in analog trigger display mode. I cannot further help, maybe someone else.

Regards, Coen (BioSemi)

sofia doly
Posts: 3
Joined: Mon Mar 15, 2021 5:14 pm

Re: strange event names of triggers on Actiview

Post by sofia doly »

I am sorry, I understand totally different thing, please excuse me I am very sleep deprived at this point in life.
Alright I investigate the analog triggers. There is no color lines on 1,3,5,7,9,13,15.

What does this mean? Should I name the trigger event names as 2,4,8,16? Or is there any way to fix this? What is the cause of this?

Thank you so much for your help. I appriciate a lot Coen --

neurospecag
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Joined: Wed Feb 12, 2020 8:34 am

Re: strange event names of triggers on Actiview

Post by neurospecag »

Hi Sofia

Since you are in Switzerland, and we represent Switzerland exclusively, and also since the issue is a PST problem, it makes little sense to go on the Forum.
In any case, let me give you the actual answer(s) on your issue:
1) When using E-Prime, and Chronos you have to use the Chronos Adapter (https://shop.neurospec.com/chronos-adapters) as well. You must use the correct Adapter as you may have also another one there for Biopac, etc, so it should say Biosemi accompanied by the logo of Biosemi on the adapter - so basically like on our shop displayed.
2) With that Chronos Adapter (SCSI to DSUB25) you must also use the supplied Trigger Cable from PST - you cannot use the originally supplied DUSB25-DSUB37 cable that came with the system then. The pin out is wrong on the standard DSUB25-DSUB37 cable from us, Biosemi or wherever else sourced.
3) If you are using all these articles, and you still get wrong coding, I suggest you disconnect the CHRONOS and route the triggers out via our MMBTS (https://shop.neurospec.com/mmbt-s-trigger-interface-box) or a standard LPT port and use the original BioSemi Trigger DSUB25-DSUB37 cable and verify whether the triggers are correct. If so, you have a problem with either the PST Trigger Cable, the Chronos Adapter, or the Chronos itself - or lastly, you have not correctly setup the paradigm.

As Coen suggest, you can always switch in ActiView where the triggers are displayed to the Analog Trigger Mode, that will show you color bars starting with a Brown Color indicating you are sending the marker 1. It then builds up until Marker 255 which are all 8 colors nicely displayed.

Again, I am pretty sure,that you are using the wrong combination of either a wrong Chronos Adapter that does not say BIOSEMI, or then a standard LPT cable to DSUB37 -
thanks, Marc

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