Disappearing time stamps and displaced markers
Here is the situation: we have a visual presentation on eprime, and we record electrodermal activity with a BioPac MP150. Then we analyze the data in a subprogram of Matlab called Ledalab (which graphs and analyzes EDA activity). We set up an in-line on e-prime before the visual stimuli to create a marker that would be visible on Acqknowledge and tell us when the participant is viewing the image on Ledalab, but neither of these things is happening correctly. In Acqknowledge, there are no time-stamps for the event even though it is programmed to do so, and in Ledalab (where it does show the timestamps), the marker somehow got displaced to after the picture. Here is a more detailed description of the set up we have on e-prime:
In our trial proc we have the stimulus block, which uses a block list at the beginning of the section to randomly generate an image. The block list has an attribute called StimType where each image is assigned a value of either 1 or 2 depending on the type of image it is.
In the image stimulus block there is a task event: StimuliB.OnsetTime, it has 0 delay, the task is the WriteByte action to a ParallelPort. The Source is (custom), in the Custom box we have [StimType] in order to record the type of image. Data type is integer. It is enabled.Directly after the stimulus block is an inline that Toggles the port off code: WritePort &H378, 0
Does anyone know what might cause the time stamps to not show up in Acqknowledge, and the marker to be displaced in Ledalab?
You might find more help at the E-Prime Google Group, groups.google.com/group/e-prime.
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