Trigger event markers from Eprime to BIOPAC

[Scott]

I'm not sure I should reply to such an old thread, but I am asking Paul 
Groot for elaborate regarding part of his post to this topic -- and my 
question still is about "...markers from E-Prime to BIOPAC."  Can you 
please explain how one can "...use a calculation channel to convert the 8 
digital channels back to a numerical one...", if one needs more than 8 
unique marker codes?

I am just beginning work on  E-Prime programs that will send triggers via 
the parallel port to Biopac equipment. I have written quite a few E-Prime 
programs for ERP studies that send codes to Neuroscan amps. For that, it's 
simple to use different numbers (1-255) to distinguish various kinds of 
stimulus onset and offset and response events. I think I understand how to 
send a signal to one of 8 channels of the Biopac recording system using 
port codes that are powers of 2 (as you explained). However, I don't expect 
that will always be enough, so I'd like to know how to setup a "calculation 
channel" to facilitate the use of more than 8 codes with Biopac. Can you 
explain, or point me to some documentation about this?

Thanks. - Scott


On Thursday, March 29, 2012 3:43:24 PM UTC-5, Paul Groot wrote:
>
> Hi Catarina,
>
> The SendPulse inline script of your es-file already contains a few
> lines to send a pulse using WritePort. You could replace them with
> something like this:
>
> DutWords.OnsetSignalEnabled = True
> DutWords.OnsetSignalPort = &H378
> DutWords.OnsetSignalData = c.GetAttrib("marker")
>
> DutWords.OffsetSignalEnabled = True
> DutWords.OffsetSignalPort = &H378
> DutWords.OffsetSignalData = 0  ' reset all digital lines to zero
>
> Since BioPac will acquire the 8 digital TTL lines as separate signals,
> you would probably want to use powers of two for the markers:
> 1,2,4,8,16,32,64 and128. *If you don't use powers of two, you will get
> a mixture of simultaneous pulses. (You could use a calculation channel
> to convert the 8 digital channels back to a numerical one, but I would
> suggest you should only do this when you need more than 8 unique
> marker codes.)*
>
> Also make sure that the marker attribute is defined in all relevant
> lists, because I  noticed that the second part of your exp. is missing
> the marker attribute.
>
> I also have the feeling that part of your script contains duplicate
> (identical) objects. Perhaps you need duplicates in some places to be
> able to implement English/Dutch specific elements, but I'm sure that
> in some places you could (re)use the same E-Object. (For example
> Blank1 and Blank2 are probably identical). Although this is not a big
> deal in your script, I often see scripts having large amounts of
> copied objects. One of the side-effects of having duplicates is that
> the log-file will become unnecessary complex.
>
>
> Best,
> Paul
>
>
> 2012/3/29 Catarina Azevedo <catarina.m... at gmail.com <javascript:>>:
> > Hi all!
> >
> > I'm new in eprime and so I realize that this will be a beginner
> > question.But I really need some help!
> >
> ...
>
>

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