Re: comedi_calibrate with ni_pcimio (NI 6023E)

From: Bob Estes <estes_at_transmeta.com> · Date: Sun, 30 Nov 2003 00:49:39 -0800 (PST)

I'm quite confused about the calibration stuff too.

I noticed the same thing with my pci-6036e card and also couldn't figure
out how the calibration stuff was supposed to work.  I don't know if this
is right, but its what I tried ...

void
calibrate_channels()
	{
	int i, channel, range, aref;
	for (i = 0; i < n_chan; i++)
		{
		channel = CR_CHAN(chanlist[i]);
		range = CR_RANGE(chanlist[i]);
		aref = CR_AREF(chanlist[i]);
		if (comedi_apply_calibration(device, subdevice, channel, range, aref, NULL) < 0)
			{ comedi_perror(deviceName); exit(0); }
		}
	}

I originally had about 7mV DC offset in my measurements which seemed to go
away after I rebooted.  I currenty have the above code disabled.  I also
read in the manual for the card something about the calibration being
applied automatically when needed ...

-B

> Hello!
> 
> 
> I use comedi 0.7.67 and comedilib 0.7.21. When calling comedi_calibrate 
> 
> linux:/ # comedi_calibrate
> eeprom reference lsb=90 msb=0
> resulting reference voltage: 5.00009
> Id: comedi_calibrate.c,v 1.89 2003/08/08 17:38:59 fmhess Exp
> Driver name: ni_pcimio
> Device name: pci-6023e
> Id: ni.c,v 1.98 2003/08/02 03:20:22 fmhess Exp
> Comedi version: 1.0.0
> Applied calibration for subdevice 0, channel 0, range 0, aref 0
> linux:/ #
> 
> is done. But what is with the other subdevices? "comedi_calibrate --help" and
> "man comedi_calibrate" didn't help. Do I need to calibrate every device and
> subdevice? Or is something wrong with comedi? 
> 
> Greetings
> 
> Mirko
> 
> 
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