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Trigger AcqKnowledge (Biopac) through LabJack


Dear all,

I have an experiment using builder with an I/O component with the port address set to LabJack and a LabJack U3 connected to a Biopac system (MP150). More specifically, from JabJack go to the correspondent inputs on the backside of Biopac’s UIM-100C.

In the computer** I have PsychoPy (v1.85.6) running, I’ve installed the last version of LabJackPython (2.0.0) as instructed on their website (link), but I couldn’t trigger any of the AcqKnowledge’s digital channels… tried numbers from 0 to 15 on PsychoPy I/O component “start data”, as well as 16, 32, 64 … and from 200 to 255. Nothing works to trigger Digital channels on AcqKnowledge. The experiment does not crash, as it did before installing LabJackPython or when USB is not connected, it just won’t trigger the channels on AcqKnowledge…

Any idea what I might be doing wrong?

Any suggestion highly appreciated.



  • (LabJack to UIM100C)
    FI00 to DIGITAL I/O 0

    FI06 to DIGITAL I/O 6
    FI07 to +5V TRIG
    Ground to GND D.

**a MacBook Pro 13 with a OSX 10.9.5 installed


PsychoPy comes with its own version of the LabJack library, so there should be no need to install it for use with Builder (when you did, it probably went in to your system Python rather than PsychoPy anyway).

You will need the driver installed, though (although I guess you might have gotten an error message if it isn’t available).

There is a LabJack demo available from the Coder view’s “Demos -> Hardware” menu. What happens if you try using that?


Thanks so much Michael.

That’s true, I got the error before installing the driver. Now I don’t, unless I have either the USB disconnected from the notebook or the cable disconnected from LabJack (“couldn’t open device”), which makes me think LabJackPython is being used by PsychoPy and it recognize the hardware.

When I open the demo you instructed me, I can run it (as long as I have LabJack connected to the computer). Any key press triggers a brief sound, during which the black square becomes white, but I se no pulse in any of biopac’s acqknowledge digital channels.

I see in the code that FIO4 = 6004, that’s the sequence in the builder as well? FIO0 = 6000 to FIO7 = 6007 ?

Thanks again.



EDIT/UPDATE: using a code component in my builder experiment and including the code I extracted from the demo you instructed instead of using the builder I/O I was able to trigger LabJack. Couldn’t make the builder I/O work though