Trigger from parallel port

[ccwu]

Hi,

How do I set up a worksheet so that data is only recorded when there is a trigger that comes from an external source's parallel port?

I am using DasyLab to record 2 channel EMG, but only want to it to record for 3s periods after each trigger. 

The triggers are sent from a separate computer using a parallel port, and we have a cable that connects this port to one of the channels of the biovision input box. However I'm not sure how to set up a worksheet (eg. should the input to the trigger be NI-DAQmx>digitalinput module, and if so how should I configure this?)

I have tried setting up a combi-trigger (pre = 0 and post = 3s) that controls a relay which should control the other channels but not sure how to get it to read the parallel port info.

If anyone can give advice it would be greatly appreciated!

Thanks very much,

Carolyn

[Dan_K]

Hello Carolyn,

What exact hardware are you using in the system? I understand you are using this biovision input box, if you could post a link to this product's website it would be helpful. Also, what National Instruments hardware are you using in the system. I assume that you are using some sort of DAQ device.

If you are, you should be able to connect the input signal line from the parallel port into PFI0 of your DAQ device and set up your task to trigger off of that line. From there you can set up you acquisition to run for only 3 seconds.

If you are not using a National Instruments Data Acquisition device and your current device does not use the DAQmx API for it's operation you should not be using the DAQmx API for this trigger. If this is the case you should contact either the manufacturer of your device or DASYLab. You can go to DASYLab's support site here.

[ccwu]

Thank you for your reply. I have contacted Biovision to check with them about being a DAQ device but haven't heard back yet - this is their product: http://www.biovision.eu/biovision1_en.htm . The NI software and drivers came with the package.

We want to read triggers in via the parallel port to control the recording of analog input (EMG signal) on a separate channel - and we now have a cable connecting the pp into a channel of the DAQ device - but if it is indeed a DAQ device, should we be configuring a digital input task for this?

Regards,

Carolyn

[Dan_K]

Hello Carolyn,

It all depends on exactly how you want to set up the task. If the device from Biovision is based on our DAQ devices there should be an input available on PFI0 that would allow you to use a digital edge as a start trigger for your analog input task. You would configure this as part of your analog input task.

As far as reading a digital input off of the parallel port, this cannot be done with NI-DAQmx, but it may be possible to use NI-VISA to perform this type of acquisition and then trigger your device in software.

There is a Developer Zone Example Program that could be modified to perform this type of task:
Developer Zone Example: Using VISA to Access the Parallel Port in LabVIEW

[CJ_Butler__DASYLab_Pro]

If the Biovision box is using a NI-DAQ or NI-DAQmx based card, you can still use the parallel port through the DASYLab Sound Card driver.

Check the Measurement/Hardware/Driver setup to verify which driver is loaded as the "traditional driver". You should also notice the NI-DAQ or NI-DAQmx driver settings in the same sub-menu.

If the sound card driver is not loaded, you may need to use the Measurement/Driver Selection menu to choose the sound card driver. Refer to the sound card driver help for the LPT pins and how they map to a Driver/Digital Input.

Good luck ....