- From: David MacMahon <davidm_at_astro.berkeley.edu>
- Date: Wed, 19 Jul 2006 12:30:11 -0700
Frank Mori Hess wrote:
> On Wednesday 19 July 2006 01:35 am, David MacMahon wrote:
>
>>I can't see how to
>>include two different CR_ALT_SOURCE channels in a cmd's chanlist.
>
> No, you can't. The calibration sources are always read from channel 0
> anyways.
Bummer. This means that AREF_OTHER is more versatile than
CR_ALT_SOURCE. For example, I can use comedilib's cmd program with
AREF_OTHER to sample my PXI-6031E's ground and 5V calibration sources...
$ cmd -f /dev/comedi1 -s 0 -o -r 0 -c 4 -n 2 -N 5 2>/dev/null
32610 49014
32610 49014
32609 49014
32608 49013
32609 49013
Since AREF_* is per channel, I can write a program with a comedi_cmd
whose chanlist uses AREF_DIFF for my analog inputs and AREF_OTHER for
these two calibration channels. I can't do that using just CR_ALT_SOURCE.
I'd like to lobby for Comedi to provide "official" support for access to
multiple calibration sources using comedi_cmd (not just via the
apparently deprecated AREF_OTHER) including reading the temperature
sensor. I need to sample the analog inputs continuously and I would
like to sample the two calibration sources and the temperature sensor
along with the analog inputs so I can tell whether fluctuations that
appear in my sampled data correspond to fluctuations in the reference
voltage(s) and/or temperature of the digitizer.
>>Furthermore, at least on the E series NI MIO boards, the on-board
>>temperature monitor lives in a different "channel space" ("auxiliary" is
>>the word that NI uses) from the calibration sources. There appears to
>>be no way to get the NI driver to select the temperature monitor as an
>>input using CR_ALT_SOURCE/INSN_CONFIG_ALT_SOURCE.
>
>
> What documentation are you using to figure out how to access the
> temperature monitor? I don't remember seeing anything about it.
It's in the "PCI E Series Register-Level Programmer Manual" (see pages
3-11 through 3-15)...
http://www.ni.com/pdf/manuals/341079b.pdf
Interestingly, it's not mentioned at all in the "AT-MIO E Series
Register-Level Programmer Manual"...
http://www.ni.com/pdf/manuals/340747c.pdf
I wonder if it exists on the AT-MIO E Series boards and is undocumented
or if it's just a feature of the PCI E Series boards.
Dave
Received on 2006-07-19Z18:30:11