Hardware timed DIO pattern generation and AI triggering with 6071e board

Hardware timed DIO pattern generation and AI triggering with 6071e board

Post by wwilbank » Fri, 27 Jan 2006 03:43:08


I am attempting to use 4-6 DIO lines to continuously generate a hardware timed patterned waveform that cycles a device and triggers a simultaneous analog input capture on 10-15 channels using a single PCI6071e card. Is this physically possible or just wishful thinking?
 
I found an DIO example vi for the 6534 card (DAQmx-6534_Cont_Gen_Onboard_Mem.vi) that I thought I could modify to work with the 6071 card that I have installed, but I get a timing error with the Sample Clock. Apparently I am restricted to On Demand timing which enable simutaneous AO, which I do not need but can live with if I could get past the error. Also the DAQmx timing vi does not even have the On Demand option available in the polymorphic vi selection. I tried adding a timing property node to select On Demand which also failed. Any enlightenment in the area of hardware-timed DIO and Simultaneous AI capture would be greatly appreciated.
 
 
Another viable option is to use a >2 AO card in addition to the 6071 for AI. I would then need to have a single clock control both the AO and AI to maintain synchronization between both cards. Any experience here?
 
 
Kindest Regards,
Bill Wilbanks
 
 
 

Hardware timed DIO pattern generation and AI triggering with 6071e board

Post by Travis G » Sat, 28 Jan 2006 06:44:26

Hello Bill,



The NI PCI-653x Digital I/O boards are a special line of products that
have the ability to perform hardware timed digital I/O. 
Unfortunately, your NI PCI-6071 E-Series card is limited to software
timed digital I/O operations, and does not have the ability to perform
any kind of hardware timed digital I/O.  The 'On Demand' timing
parameter is synonymous with software timed digital I/O.  Software
timed digital I/O operations are programmed in NI-DAQmx by not using
the DAQmx Timing VI.  You simply create your digital task, start
it, and then read or write to digital lines through software
commands.  This explains the lack of an 'On Demand' option for the
DAQmx Timing VI.



What I would best recommend for your application is one of our M-Series
devices (NI PCI-62xx).  This new line of Multifunction DAQ devices
maintain the ability to acquire analog input signals, and include the
functionality of correlated digital I/O operations on port 0.  A
correlated digital I/O operation enables the coupling of buffered
digital I/O operations with the analog, counter/timer, or an external
clock.  Here is a good overview of digital I/O applications, and
also an example program showing how correlated digital I/O is performed
with M-Series devices.


<a href=" http://www.yqcomputer.com/ " target="_blank">Developer Zone Tutorial: Digital I/O Applications</a>

<a href=" http://www.yqcomputer.com/ ;p_node=201229&p_source=External" target="_blank">Developer Zone Example: Performing Correlated Digital IO with an M Series Device in LabVIEW</a>

I hope this helps!

Regards,
Travis G.
Applications Engineering
National Instruments
www.ni.com/support

 
 
 

Hardware timed DIO pattern generation and AI triggering with 6071e board

Post by Michael » Thu, 02 Feb 2006 02:40:57

Bill,
Take a look at the example named Acq&Graph Voltage-Int Clk-HW Trig Restarts.vi (under Hardware Input & Output>DAQmx>Analog Measurements). This example demonstrates how to acquire a finite amount of data (waveform) using the DAQ device's internal clock, each time an analog trigger condition is met.  Additionally, the example shows how to efficiently restart the task therefore running at optimal speed. So, you can retrigger an acquisition based on an analog trigger. Integrate this capability into your application to get the desired operation.
 
 
 

Hardware timed DIO pattern generation and AI triggering with 6071e board

Post by wwilbank » Thu, 02 Feb 2006 06:10:55

Michael,
I cannot find the example in Hardware Input and Output/DAQmx/Analog Measurement with HW trigger in the name. Is this available in Labview 7.1?
Regards,
Bill
 
 
 

Hardware timed DIO pattern generation and AI triggering with 6071e board

Post by wwilbank » Thu, 02 Feb 2006 09:40:53

Michael,
I am using DAQmx 7.4. I will download version 8 and have a look.
Regards,
Bill