Digital Out and Counter DAQ Card

[olm]

Hello,

i have a NI-DAQ Card PCI-6733 and i would like to use the DAQmx driver to use it.

What i would like to do is i want to to configure the digital output to send a trigger

to another device. Immedeately after the trigger i want to start counting with the

Counter for a given time. So the trigger i send to the other device could be used

to also trigger the counter.

Unfortunately i think the manual for the DAQmx Driver to be very confusing. It says

most cards only can run one task - and one task may only contain one type of input

or output. So in this case it would be necessary to somehow run trigger and counter

together as the counter would already have to wait for the trigger, while in parallel i create

my digital output.

I really don't understand how to do this with the DAQmx Driver and all the synchronisation

examples and stuff i find on the NI page don't help me to understand what happens and

how the driver actually works. I don't really get an understanding of the Driver, though i

read a lot about it. I just can do simple things like give a signal to an output. But more

complex tasks seem nearly impossible to me with this (IMHO bad) driver.

Thanks in Advance,

    Olm

[ZwJoh]

Hi Olm,

It seems to me that you are facing different problems:

#1- What is a task?

#2- What is synchronisation?

#3- How does your card work?

#4- How could you create a working programm?


#1

Tasks contain all the information needed to acquire or generate a signal. This includes timing information, and triggering information.

Each NI-DAQmx task can only include channels of the same type.

If your application requires you generate a digital output and an analog input you need to create two tasks.

One task for the digital output and one task for the analog input.

However, if you are reading two analog inputs you can create one task to read both of these inputs.

Every setting in your task can be implemented directly in LV, too. It can be more comfortable to sum all of the configuration settings up in one item.
The limits of task is set by the number of A/D or D/A converter.
So, if your cards has multiple A/D-converter or multiple D/A-converter, you can define different sample rates for different channels of the same type.

#2
Timing and Synchronization Features of NI-DAQmx
https://www.ni.com/en/support/documentation/supplemental/06/timing-and-synchronization-features-of-n...

Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications
https://www.ni.com/en/support/documentation/supplemental/06/learn-10-functions-in-ni-daqmx-and-handl...

#3
Take a closer look under specifications on this two pages:
https://www.ni.com/en-us/support/model.pci-6733.html
https://www.ni.com/docs/en-US/bundle/ni-6711-6713-6722-6723-6731-6733-features/resource/370735f.pdf

A trigger is a signal that causes a device to perform an action, such as
starting an acquisition. You can program your DAQ device to generate
triggers on:
• a software command
• a condition on an external digital signal

You can also program your DAQ device to perform an action in response to
a trigger. The action can affect:
• analog output generation
• counter behavior

#4
I would suggest you to use a software trigger. Select a digital channel, connect it to the system which should be started by triggering and last but not least
set the value of the channel to true.
Now- you have to synchronize the digital output to the measurement of the counter signal.
There are plenty of examples in the example library. Try them! You can search for examples especially for your hardware!