[Rtai] Comedi calibration file routines under RTAI

Jordi Blanch Carles jordi_blanch at encopim.com
Tue May 20 17:05:24 CEST 2008

Quoting Paolo Mantegazza <mantegazza at aero.polimi.it>:

> Jordi Blanch Carles wrote:
>> Hello everybody,
>> we would like to use the methods for extracting calibration values   
>>  stored in the files generated with comedi_soft_calibrate with  
>> RTAI,   but this methods (like parse_calibration_file and    
>> apply_parsed_calibration_file) are not in rtaicomedi.h.
>> Is there any problem for using this methods under RTAI, so that   
>> they  aren't included in rtaicomedi.h for a technical reason? How   
>> could we  use them with an RTAI enabled system (but not in a real   
>> time task)?
> I'm likely speaking on the base of un insufficiente knowledge,
> nonetheless let's try, to understand at least.

Sorry, I've not explained our problem deep enough. We have created a  
"comedi_sensor" class to access NI's 6229 analog input channels. We  
would like to use this mentioned methods at object's creation time  
(class constructor) to get the calibrations saved in file with  
comedi_soft_calibration utility. The class has also "get()" methods  
that make calls to rtai_comedi methods in order to acquire values for  
an analog channel. Our problem is that we cannot include both  
rtai_comedi and comedilib in the class definition file because the  
compiler complains about it (some of the methods defined in  
rtai_comedi are also defined in comedilib).
We won't use the calibration methods in real time, just once in object  
creation, out of any real time task.

That's why I was asking if there is any technical reason that makes it  
impossible to add this methods into rtai_comedi... or maybe there is  
still something I'm not aware of...

> I do not see such services in comedi but in comedilib, am I right?.
Yes, you are wright, sorry for the mistake.

> If so notice that RTAI COMEDI support is based on COMEDI's kernel
> support directly. You cam use comedilib directly within RTAI for the,
> likely non real time, services that are not provided by rtai_comedi.
> I think that the functions you mention can be used as they are within
> the initialisation phase of RTAI, i.e. before going to hard real time.
> Do you need parsing and applying calibrations continuoulsy while in
> hard real time instead?
>> Thanks a lot!

Thank you again.

Jordi Blanch Carles
Unidad de Ensayo y Control

C/. del Parc, 5 (nave 13)
P.I. Els Pinetons
E-08291 RIPOLLET (Barcelona)
Tel: (+34) 935 94 23 47
Fax: (+34) 935 94 64 15

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