RE: Calibration problems

From: hhumphre <hhumphre_at_utk.edu> · Date: Wed, 26 Jul 2006 11:39:34 -0400

I'm not sure I'm calibrating correctly.  I'm not running the calibration in my 
startup scripts.  I'm doing it manually in the terminal.  I am just doing the 
following:

[root_at_odex comedi_calibrate]# ./comedi_calibrate
eeprom reference lsb=130 msb=253
resulting reference voltage: 4.99936
Id: comedi_calibrate.c,v 1.92 2004/03/29 01:34:15 fmhess Exp
Driver name: ni_pcimio
Device name: pci-6036e
Id: ni.c,v 1.130 2004/09/09 21:43:16 fmhess Exp
Comedi version: 0.7.70
Applied calibration for subdevice 0, channel 0, range 0, aref 0

I've read that the NI-6036E board that I'm using generates an internal voltage 
of 5 Volts for calibration.  So the resulting reference voltage looks good.

It's the last line of the output that I'm questioning.  Does this mean that 
it's only calibrating subdevice zero and channel zero?  Do I need anything 
else in my execution command?  Do I have to somehow tell it what channels, 
etc., to calibrate?

Also, the Comedi documentation suggests that I ground all unused channels.  I 
can do that if it will help, but it requires a lot of wires.  Has anyone tried 
that?

Thanks,

Heather

>===== Original Message From Maz The Northener <mazziesaccount_at_gmail.com> 
=====
>Hi dee Ho!
>
>I'm not at all sure I'm correct with this but I'll throw my 10 cents
>in. It cant harm right?
>1. Settling time must be large enough with my DAQ card. Othervice I'll
>get odd results. Add some sleep between measurements :)
>2. I'm not sure if it's good idea to put the calibration script in
>startup. I have experienced some problems with my PCI-DAS card's
>calibration when I have calibrated it and computer has been under
>heavyish use. Can you see the output of calibration program? There's
>no warnings present? Also, at least with my card, the card should have
>warmed up properly before calibrating it. I need to keep the comp
>running ~10 mins before doing the calibration. (Although errors you
>described sounds largish...)
>
>Well, as I said, I doubt this message harms anyone :)
>
>--
>BrakesAreForCowards!!!
>When you feel blue, no one sees your tears... When your down, no one
>understands your struggle...
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