Scaling in VI Logger Lite 2.0.1 not working properly

[Micah Digman]

We are having a problem using a custom scale in VI Logger Lite 2.0.  One of the two channels is not correctly applying the scale we are entering.  We are trying to scale the value by 60, but it is applying a value of about 31.2 instead.  I have attached screen shots in the Word document.

[Justin_M]

Hi Micah,

One thing that I noticed from your attached screenshots is the range you have set for your scaled voltage.  Once you apply a custom scale, that range actually corresponds to the scaled value.  So in your case, that should be set to 0-300 instead of 0-5 (notice the units to the right say "Supply Volts").  I'm not really sure why it didn't max out at 5 though...

In any case, try resetting that range and see if that fixes the problem.  Let us know what happens!

Thanks,

Justin M.
National Instruments

[Micah Digman]

You have me a little confused with the range comment.  Our device is putting out a 0-5V signal, which correspongs to a 0-300VAC supply voltage that is being read.  From this I would expect a scale rating of 60 (1V signal = 60 Volts AC) and a range of 0-5V.  Isn't the range the range of the value that is being measured by the device?

[Justin_M]

Micah,

If you've ever made a special type of task in Measurement and Automation Explorer, such as a temperature task, it works the same way.  Say you are doing a thermocouple measurement, which measures voltages that are smaller than 1V.  The Range would look something like this:

Note that the range referrs to 0-100 degrees C, not 0-100 V.  DAQmx knows to apply the reverse scale to the 0-100 range, which would correspond to the actual voltage values read by the card.

Thanks,

Justin M.

National Instruments

Message Edited by Justin M. on 06-09-2006 03:59 PM