[Xenomai-help] DAQ SYSTEM COMPATIBILITY

[Xenomai-help] DAQ SYSTEM COMPATIBILITY

[Antoine Nourry]

Hi all,
i need to buy an USB DAQ system and use it with Xenomai. I have an eye 
on the National Instruments USB 6218 which is provided with linux drivers.
How can we now if an hardware will be usable with Xenomai ? Do we need 
the driver sources in order to be able to rewrite it for real time 
purposes ?

Thanks,
Antoine

Re: [Xenomai-help] DAQ SYSTEM COMPATIBILITY

[Alexis Berlemont]

Hi,

> i need to buy an USB DAQ system and use it with Xenomai. I have an eye
> on the National Instruments USB 6218 which is provided with linux drivers.
> How can we now if an hardware will be usable with Xenomai ? 
> Do we need 
> the driver sources in order to be able to rewrite it for real time
> purposes ?

A nice way would be to recover the Linux driver and make it work with Comedi 
(which is a kind of framework for acquisition drivers, an RTDM port is 
available).

Do you have the driver sources ? Just to see how it works...

To fully comply with real-time constraints, maybe usb20rt might be 
necessary...

Best regards.

Alexis.

Re: [Xenomai-help] DAQ SYSTEM COMPATIBILITY

[Anders Blomdell]

Alexis Berlemont wrote:
> Hi,
> 
>> i need to buy an USB DAQ system and use it with Xenomai. I have an eye
>> on the National Instruments USB 6218 which is provided with linux drivers.
>> How can we now if an hardware will be usable with Xenomai ? 
>> Do we need 
>> the driver sources in order to be able to rewrite it for real time
>> purposes ?
> 
> A nice way would be to recover the Linux driver and make it work with Comedi 
> (which is a kind of framework for acquisition drivers, an RTDM port is 
> available).
> 
> Do you have the driver sources ? Just to see how it works...
> 
> To fully comply with real-time constraints, maybe usb20rt might be 
> necessary...
Another thing to keep in mind when using USB, is that USB microframes/frames are
only sent each 125 us/1 ms which gives a limit to how fast a control loop can
possibly be closed over USB (8kHz/1kHz, which is way below what can achieved
with USB if only data acquisition is needed).

Best regards

Anders Blomdell


-- 
Anders Blomdell                  Email: anders.blomdell@domain.hid
Department of Automatic Control
Lund University                  Phone:    +46 46 222 4625
P.O. Box 118                     Fax:      +46 46 138118
SE-221 00 Lund, Sweden

Re: [Xenomai-help] Daq System Compatibility

[Antoine Nourry]

Alexis Berlemont a écrit :
> Hi,
>
>   
>> i need to buy an USB DAQ system and use it with Xenomai. I have an eye
>> on the National Instruments USB 6218 which is provided with linux drivers.
>> How can we know if an hardware will be usable with Xenomai ? 
>> Do we need 
>> the driver sources in order to be able to rewrite it for real time
>> purposes ?
>>     
>
> A nice way would be to recover the Linux driver and make it work with Comedi 
> (which is a kind of framework for acquisition drivers, an RTDM port is 
> available).
>
> Do you have the driver sources ? Just to see how it works...
>
> To fully comply with real-time constraints, maybe usb20rt might be 
> necessary...
>
> Best regards.
>
> Alexis.
>
>
>
>   
First of all, thank you for your answer.

I would appreciate to make it this way. The problem is that i don't know
if NI give its sources (i'm downloading an ISO from their site...), and
i can't afford to buy a system i won't be able to use.
Generally speaking, what do we need to make a DAQ system work on a
real-time linux solution ?

Do we absolutely need the native driver sources or can we find the
necessary answers for making a new real-time driver in documentation and
hardware specifications ?

Anyway, it seems to be a harsh task to write a new driver according to
many comments.

Re: [Xenomai-help] Daq System Compatibility

[Alexis Berlemont]

Hi,

> Do we absolutely need the native driver sources or can we find the
> necessary answers for making a new real-time driver in documentation and
> hardware specifications ?

It depends on the size of the documentation and the accuracy of its details ;) 
I had a quick look at NI web site, I only found a global datasheet.

> Anyway, it seems to be a harsh task to write a new driver according to
> many comments.

Comedi is supposed to make this task easier. 

Best regards.

Alexis.

[Xenomai-help] Daq System Compatibility

[nourry]

Hi,

> That seems to be an example showing how to use the driver. That will not help
> us to write the driver. The hardware access are abstracted / encapsulated by
> DAQmx functions.


Alex, do you think this sample looks more like a driver ?
It comes from NI Development Kit and i saw on NI forum that someone was
developing a driver from that sources for a PCI card in order to make it work
under Xenomai. He had some problems but he seems to manage to initialize the
card and program interrupts.

//

//  common.cpp

//

//  $DateTime: 2006/07/27 23:51:45 $

//

#include "common.h"


void analogTriggerReset (tMSeries* board)

{

    board->Analog_Trigger_Etc.setAnalog_Trigger_Reset(1);

   
board->Analog_Trigger_Etc.setAnalog_Trigger_Mode(tMSeries::tAnalog_Trigger_Etc::kAnalog_Trigger_ModeLow_Window);

    board->Analog_Trigger_Etc.flush();



   
board->Analog_Trigger_Control.setAnalog_Trigger_Select(tMSeries::tAnalog_Trigger_Control::kAnalog_Trigger_SelectGround);

    board->Analog_Trigger_Control.flush();



    board->Gen_PWM[0].writeRegister(0);

    board->Gen_PWM[1].writeRegister(0);



   
board->Analog_Trigger_Etc.setAnalog_Trigger_Enable(tMSeries::tAnalog_Trigger_Etc::kAnalog_Trigger_EnableDisabled);

    board->Analog_Trigger_Etc.flush();



    return;

}


Thank you,
Antoine

Re: [Xenomai-help] Daq System Compatibility

[Alexis Berlemont]

Hi,

> > That seems to be an example showing how to use the driver. That will not
> > help us to write the driver. The hardware access are abstracted /
> > encapsulated by DAQmx functions.
>
> Alex, do you think this sample looks more like a driver ?
> It comes from NI Development Kit and i saw on NI forum that someone was
> developing a driver from that sources for a PCI card in order to make it
> work under Xenomai. He had some problems but he seems to manage to
> initialize the card and program interrupts.

Would you mind sending the URL of the post on that forum?

Thanks in advance.

Alexis

[Xenomai-help] Daq System Compatibility

[nourry]

Hi,
here is the URL :

http://forums.ni.com/ni/board/message?board.id=90&message.id=815&query.id=104393#M815


> Would you mind sending the URL of the post on that forum?

> Thanks in advance.

> Alexis

Bye.