Can Eprime work with Neuroscan?

[Stephen D. Benning]

On Tue, 2004-02-24 at 08:01, Richard P. Heitz wrote:
> I'm using a neuroscan with E-Prime, and am having a problem with triggers
> getting through (I've posted this problem before).  I haven't found any
> remedies.  I randomly lose approximately 7% of all triggers.  Leon, if you
> end up having this problem too, I'd like to hear about it.

A few questions that might help debug your problem, listed in order of
decreasing probability:

1)  Do you have any statements of the variety (assuming that 0 is your
"hold value"):

	WritePort TriggerPort, 0
	WritePort TriggerPort, TriggerValue

or
	WritePort TriggerPort, TriggerValue1
	WritePort TriggerPort, 0
	WritePort TriggerPort, TriggerValue2

If so, it's likely that the port can't be consistently reset to the hold
value before the next trigger comes.  Therefore, you won't have
consistently occurring triggers.  To remedy this problem, you can use
code like this (if all else fails):

	WritePort TriggerPort, 0
	Sleep 1
	WritePort TriggerPort, TriggerValue

This will force E-Prime to pause for a millisecond to allow the hold
value to be written.  You may need to adjust program timing to account
for this 1 ms slop, though.

2)  Are you having more programs than just E-Prime running when you're
running your experiment?  IF so, Windows might be calling those programs
at unexpected times (though if this were the case, I'd expect to see
random pauses in the experiment altogether, rather than just trigger
dropping).

3)  Is the cable connecting your output port to the Neuroscan unit
firmly attached?  Sometimes flaky cable attachments can drift off at the
oddest times.

4)  Is your parallel port working consistently?  Likewise, is the
Neuroscan equipment EVER able to receive triggers consistently?  IF not,
you may have a hardware problem.

> ----------------------------------------------------------------------------
> ----------
> Richard P. Heitz, M.S.
> Attention and Working Memory Lab
> Georgia Institute of Technology, Atlanta Georgia 30332
> Email: gte016z at prism.gatech.edu
> Office: 350 J.S. Coon Building
> Web: http://psychology.gatech.edu/renglelab
> ----- Original Message -----
> From: "Jan Seifert" <seif1301 at uni-trier.de>
> To: "eprime" <eprime at mail.talkbank.org>
> Sent: Tuesday, February 24, 2004 5:00 AM
> Subject: Re: Can Eprime work with Neuroscan?
>
>
> > eprime，hello！
> > I am now conducting an ERP study using Neuroscan scanner. I want to
> program with Eprime instead of Stim. But I find I can only send a stimuli
> onset or offset signal(by OnsetSignalEnabled,OnsetSignalPort,OnsetSignalData
> function)  to the scanner and cannot send other signals like response to the
> scanner. How can I slove this problem?
> > Is there any other way to make E-prime work together with Neuroscan?
> > 　　
> >
> >
> > Best Wish!
> >
> > 　　　　　　　　　　　　　　                    Leon
> Hello,
>
> you can send triggers anytime and anywhere with the "WritePort" command.
> Something like this:
>
> WritePort NEUROSCANTRIGGERPORT,ATrigger
>
> Hope this helps
> Jan
>
> \
> / Jan Seifert
> / Fachbereich I - Psychologie
> / Universitätsring 15
> / 54296 Trier
> \
> / +49 651 201 2896
> \ seif1301 at uni-trier.de
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> \
--
Stephen Benning
Office: N631 Elliott Hall
75 East River Road
Minneapolis, MN  55455