Problem when trying to use triggering for NI PCI 6713 Card

[Wan81]

Hi guys,

I purchased an NI PCI 6713 card a month ago. Lately, I've been trying out the triggering function and I encountered some issues.

Under DAQ assistant, I have filled up the requirements as stated below:

Task Timing: N samples

Task Triggering -> Trigger Type: Digital edge

                               Trigger Source: PFI0

                                            Edge: Rising                     //Hence i assume that this indicates that PFI0 will wait for a signal from external hardware right?

Signal Source used to generate signal:

Signal: Square

Freq: 1hz

Amp: 2.5v

offset:2.5

Duty Cycle: 50%

Samples/s: 1000

Number of samples: Auto(100)

I've also clicked the option for the card to run as fast as possible.

However, I encountered this error below:

"Wait until done did not indicate task was done within specified timeout. Increase time out, check program and make sure connection for external timing and triggering is in place"

I don't think it is time out issue because without triggering, the DAQ assistant did not indicate any errors. connection shouldn't be a problem because I have wired the DGND and PFI0 terminals to the DC power generator providing the 5V TTL.

Can someone help me?? Urgent.

Thanks

Ridwan

[PBear]

Hi Ridwan,

You're having a timeout because in the DAQmx code that is underneath the Express VI, there is a Wait Unitl Done VI. This VI has a timeout on it that is setup under the advanced timing tab of the DAQ Assistant. It's a blocking function that allows the entire task to finish. If a trigger doesn't come in the alotted time, you will get a timeout from this VI. This is expected behavior and I would recommend setting the timeout to -1 as this will create an indefinate wait. See the picture below for a visual.



If you right click on the DAQ Assistant, you can create the DAQmx Task or Code and you will be able to see the functionality under the hood.



Message Edited by PBear on 04-29-2008 12:55 PM

[Wan81]

Hi,

I've tried out this VI from NI examples page: Cont Gen Voltage Wfm-Int Clk-Dig Start.I've just tried out the VI and it works!!

However, my application requires me to synchronize the analogue output card with a digital source such that each time PFI0 receives the signal, it will output 1 waveform. For the example above, it outputs a continuos waveform.

How can I achieve this?

I tried the 'Pretriggerable' function as I needed the card to be able to continuously output 1 waveform each time PFI1 receives a trigger input.

Thanks.. Please help

[PBear]

Hi Ridwan,

I would recommend looking at this great guide to using DAQmx. You'll find plenty of great examples and documentation about how to program many different applications.

Getting Started with NI-DAQmx: Main Page
http://zone.ni.com/devzone/cda/tut/p/id/5434

Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications
http://zone.ni.com/devzone/cda/tut/p/id/2835

[Wan81]

Hi P Bear,

Thanks for the tip. As I was surfing the developr page, I came across this page regarding NI-DAQmx: Retriggerable Analog Output -- LabVIEW. There is this example which I think can help me with my problem. However, the problem is that I can't download the file: retriggerable_ao_0001.zip.

Is there any problems with this file??

The post can be found through this URL http://zone.ni.com/devzone/cda/epd/p/id/4787

Thanks

Ridwan

[PBear]

Hi Ridwan,

It does appear that there is a bad link here. I've attached the example to this post and I'll submit a request to get this fixed as soon as possible. Thanks for the heads up!

[Wan81 · Accepted solution]

Hi PBear,

It seems that I have tried the attached example and it works great!!! Really solved my problem. However, needed some time to figure out how the subVIs work and interact. Now I thoroughly understand the VI.

Finally, I can control the output voltage waveform by adjusting the desired frequency and duty cycle values. I can also control on which trigger rising/ falling edge before outputting a voltage.

Thanks So much for the help.

[PBear]

Hi Ridwan,

I'm very pleased to hear of your success! I'd like to thank you for taking part in our community via the Discussion Forum and hope that you continue to take advantage of these resources in the future. Have a great day Ridwan.