External trigerring using PXI-6251 and SCC-68

[Sasidhar]

Hi,

We use a third party device for our data collection. It is capable of being triggered externally (high to low edge triggered).

I want to incorporate a piece of code in an existing LabVIEW program. Its functionality would be to generate a trigger when I click on a boolean START button.

We use a PXI-6251 in combination with the SCC-68. I have a cable that is connected in between SCC-68 and the desired device. The problem I face now is......even without running the LabVIEW code, whenever I enable external trigger on the device it starts data collection.

Can we somehow make the PFI line on SCC-68 stay HIGH as long as the user doesn't click START. Once user does so, it should go LOW and tell the device to start data collection.

Thank you.

[ManLongAtNI]

Hello Sasidhar,

It sounds like you want set the default state of a line to 'HIGH'. If that is the case, you can set the Power-up State of that particular line. To do this go into Measurement & Automation Explorer (MAX) and select properties of the device of interest. Make the appropriate changes under the Power-up States tab.

[Sasidhar]

Thank you for the reply.

I tried what you said earlier once. It doesn't work. When I put a multimeter across the HIGHed DigOut line it shows 0 V. I am assuming HIGH would be 5 V. So can we do a software HIGH and then LOW again when I click a boolean ctrl.

[Dennis_Knutson]

If you are reading 0V after setting the default to 1 and after powering up the pc, then you are either looking at the wrong pin or something is very wrong with how you have connected things. Disconnect your circuit and look at the output. Use MAX to control the output and you should see 5V when the output is set to high and 0V when the output is set to low. This is basic troubleshooting.

When you click a Boolean, you can perform any operation you want.