Reading from analog channel (DAQ)

[Kim]

Hi all,

I'm trying to read the output voltage from an IR device
through Channel 0 of my daq card. However there are few
issues that I'm not sure about: First of all, I'm using
"AI Sample Channel.vi" inside a while loop. The output of
this VI is connected to a numerical indicator on the front
pannel.

1- The output voltage from the IR ranges between 0 and 3 volts.
However, when i read the value of ch0 on the DAQ card i get
a totally different value (eg. if output measured from meter =0.5 v,
the daq reads 3.5).

2- I set the hi/low limits to 0/5. The help on labview says we need
to use these values to compute the gain. how do we compute it and
where do we put its value.

3- is it possible to have the daq card read the exact vo
ltage from
the IR. for example if Vout=2 the indicator on front pannel displays 2.

thanks in advance

[Dennis_Knutson]

How have you configured the channel - referenced single ended, non-referenced single ended, differential? You should be able to get the same reading from the DAQ board that you would get from a DMM but if the channel is set up for single ended and you are using differential wiring, or vice versa, the readings are going to be wrong. Check the wiring and configuration in MAX's test panel for the DAQ board. You can then use AI Config.vi in your LabVIEW program to ensure that the acquisition is done correctly even if the board config gets changed by someone messing around in MAX.

[Kim]

Thanks for the comments. It's working now.
The daq was originally configured as NRSE where
it should have been RSE.

thanks again



Dennis Knutson wrote in message news:<506500000005000000F6EC0000-1042324653000@exchange.ni.com>...
> How have you configured the channel - referenced single ended,
> non-referenced single ended, differential? You should be able to get
> the same reading from the DAQ board that you would get from a DMM but
> if the channel is set up for single ended and you are using
> differential wiring, or vice versa, the readings are going to be
> wrong. Check the wiring and configuration in MAX's test panel for the
> DAQ board. You can then use AI Config.vi in your LabVIEW program to
> ensure that the acquisition is done correctly
even if the board config
> gets changed by someone messing around in MAX.