Stimuli/ Triggers/ Timing difficulties

[David McFarlane]

At 5/3/2012 01:36 PM Thursday, Douglas wrote:
>1-I have to Synchronize Trigger with Stimulus with. What we have is: 
>Stimulus.OnsetSignalData=c.getattrib ("cond") But I have been told I 
>have to add "SynchTrigger" somewhere! Does anyone know how I can 
>Synchronize Trigger time and Stimulus time like
>they start at 0 millisec?

Read Chapter 4, "Using E-Basic", in the User's Guide that came with 
E-Prime, and see the "Context.GetAttrib" and Onset/OffsetSignal 
topics in the E-Basic Help facility.  My online course also has a 
lesson that addresses this very topic.  PST Web Support 
(http://support.pstnet.com/e%2Dprime/support/login.asp  ) might also 
help you with this.


>2-I have asked other researchers who work with e-prime on Windows7 
>and one told me eprime doesn't work well( in matters of time) with 
>Windows7. Is that true?

You may find PST's latest statements at their Knowledge Base, e.g., 
http://www.pstnet.com/support/kb.asp?TopicID=4026 and 
http://www.pstnet.com/support/kb.asp?TopicID=4347 .  We have been 
sticking to Windows XP as much as possible, but I don't know that 
that's so necessary anymore.  In any case, best practice calls for 
every lab to verify these matters for themselves rather than to rely 
on the proclomations of commercial companies who stand to make a 
profit, or random windbags on the internet like me.  So devise and 
run your own tests (perhaps using an oscilloscope or other trusted 
measuring devices).


>3-I came across one line which I don't know what exactly it is doing!
>c.SetAttrib"CondTime",clock.ReadMillisec
>Do you have any ideas?

Read Chapter 4, "Using E-Basic", in the User's Guide that came with 
E-Prime, and see the "Context.SetAttrib" topic in the E-Basic Help facility.


>4- would you please tell me what is called the time the computer 
>shows the picture and the time it shows the trigger? are they start times?

This has been discussed already.


>5- If I want triggers and stimuli to show up on monitors at the 
>exact same time( Millisec), How do I have to write the command codes?

I would use the Onset/OffsetSignal facilities of E-Prime.  See, e.g., 
the Slide.OnsetSignalEnabled and related topics in the E-Basic Help 
facility.  And my online course has a lesson that addresses this very topic.


>6- Why are we having Triggers much sooner than Stimuli? and why it 
>is variable in different stimuli? we have 200 Stimuli and I can see 
>on Iwave Triggers come sooner than Stimuli( up to 900millisec)
>
>7- If ever, anyone accepts to look at the exp.es2 to explore and 
>correct the problem, I will be grateful.

PST Web Support 
(http://support.pstnet.com/e%2Dprime/support/login.asp  ) may do that 
for you, give them a try.


>Looking forward to a huge help, desperately!

Relax, the world does not hinge on your research project.  When I was 
in graduate school, my advisor told me to slow down, science is a 
deliberative enterprise, take time to properly deliberate.  Or have 
things changed that much since the early 1980s?

-----
David McFarlane
E-Prime training 
online:  http://psychology.msu.edu/Workshops_Courses/eprime.aspx
Twitter:  @EPrimeMaster (twitter.com/EPrimeMaster)

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