Quadrature Encoder Counting and Sampling with 6024E

[amrish]

Hi,

I wish to perform buffered counting on a quadrature encoder and sample a voltage signal from a torque transducer simultaneously. Is this possible using a DAQ6024E card ? I tried using the Quadrature Encoder vi on the NI website and building a sampling routing in the counting loop but the count went terribly wrong.
System being used:
2.4 Ghz Celeron with 256 MB RAM, WindowsXP Home, LabVIEW 7.0, NI-DAQ 7.1.0f1
Any inputs will be highly appreciated.

Thanks !
Amrish

[Nipun M]

Hello,

Thank you for contacting National Instruments. You should be able to use the 6024E DAQ card for this application. The only problem that you might encounter is the fact that the 6024E has one DMA channel. You will have to use IRQ for one of the inputs and use DMA for the other one. I would recommend using DMA for the analog acquisition and using IRQ for the counter application. The following KnowledgeBase demonstrates how to setup IRQ transfers:

How do I set my DAQ device to use Interrupts instead of DMA?

A good place to get started with this application is to look at the simultaneous AI/AO example programs that ship with LabVIEW. These examples
will demonstrate how to setup the two simultaneous sampling channels. You should be able to replace the analog output with counter setup and configure the IRQ. Hope this helps out.

Nipun M
Applications Engineer
National Instruments

[amrish]

Hello Nipun,

I tried what you had suggested but still I have a similar problem with the counter not functioning properly. I tried looking for the DMA channels on the DAQ6024E card (PCMCIA) and the web page says that there are no DMA channels on the card.

How many channels does my E-series DAQ device have ?

Does this mean that I cannot perform the desired application ? Your thoughts on this will be appreciated.

Amrish