How to use USB DAQ boards under RTX?

[DaveChandler]

Hello all,
   I am a graduate student developing a control system in RTX.  The problem is that we wish this solution to be run on any of the lab PCs, which are ultra-small form factor integrated workstations providing only USB io; we cannot use PCI boards.

   I have searched these forums and saw similar requests, with the response being that RTX does not support USB, but it does now

http://www.ardence.com/embedded/products.aspx?ID=70

  so I was wondering if there is any support for data acquisition boards with USB interfaces for RTX, and if not, what kind of driver development assistance is available should I attempt to write my own.  Are the protocols / commands completely proprietary, or would I be able to work with Source / Other information to help enable the creation of RTX drivers?

Thanks!

Dave Chandler

[eek]

While RTX may support USB communication, that may not be the case with LV RT. To my knowledge, USB is intrinsically non-deterministic. While LV RT (ETS) does support file I/O to USB flash, that's pretty much the extent of it. It sounds as though you might talk with RTX to find out how it supports USB.

Cheers

[DaveChandler]

Perhaps I don't understand fully.  I am not interested in using LabView... I want to access the boards directly from within my own program.  Is there driver support for any OS for this sort of thing, or do you have to use the LabView application to get data off the boards no matter what?

[Jeremy_C]

National Instruments provides the Measurement Hardware Driver Development Kit the includes examples and some documentation for developing drivers for some NI data acquisition products.  At this time, support for USB DAQ devices is NOT provided.  With that said, what USB DAQ device were you wanting to use?  What functionality do you need for your application?

[DaveChandler]

Thanks for the response!

We hadn't really settled on a particular DAQ device...  it's really more of a 'If we can find one that works, we'll run with it'.  Our functionality is really pretty simple.  We'd need a multi-purpose board.  We need a few A to D converters, at least 2 D to A converters, and some amount of digital IO (8 bits in 8 bits out min).  All we need to do is read and write to these values.  No special buffering or anything like that.  We just want to be able to do "What is the value at this channel now"  "Write this value to this channel now" type operations.

[pierreR]

Hello,
The DAQmx Base driver driver supports Windows/RTX. With this driver you can drive a lot of DAQ cards from NI. DAQmx Base driver provides a C API in order to be use by any ANSI C compiler or any compiler ables to call DLL functions.But you must remember that USB isn't deterministic and that's why DAQmx Base doesn't support USB devices.
Regards

Message Edité par pierreR le 03-03-2007 05:02 AM

[DaveChandler]

Understood, still as I stated before, we absolutely have to use USB as the PCs in our laboratory are Ultra-small form factor and can not have additional PCI cards added to them.  Installing a DAQ card in these PCs is quite impossible.

There are numerous programs to deliver 'near deterministic' USB which should be good enough for my system.  We require soft real time execution.  This is why USB is now supported by RTX and other real time systems. 

I apologize, but I simply can not use a PCI solution.  My Real Time Operating system supports USB (Whether it is 100% deterministic or not), so all I need is some kind of support from a DAQ that lets me communicate with it.  I don't even need the driver, I'll write that myself.  I just need to know how to communicate properly with the board.

[eek]

If you are interested in writing your own driver, then perhaps it's best you look into the Driver Development Kit. Keep in mind NI does not provide full support for this kind of task. There's a specific discussion forum for the NI Measurement Hardware DDK that might provide some more input.

[beli]

Bonjour ,

pouvez m'aidez svp, car je pense que je ne sais pas comment utiliser ce forum pour poser ma question.

j'ai posé une question, mais je ne la vois pas apparaitre.

Je vous laisse mon adresse personnelle, car j'ai vraiment besoin d'une réponse.

Adresse perso:  dine.boualem@neuf.fr

Question:

comment configurer RTX pour qu'il reconnaisse un clavier avec connecteur USB, branché sur la carte mère.

OS:Windows XP PRO

RTX: version évaluation 4.0

Processeur: Intel Dual core 6600@2.40 GHz

Merci pour votre aide