select input ranges on at-mio-64e-3

[krmt]

Hi there,

i am using the fairly old AT-MIO-64E-3 DAQ card under Win2000. According to its manual and spec sheet, the  card has15 different input ranges for the AI channels.However, using MAX to configure the card, I can only choose between -10V ...+10V and 0...+10V. 

I already downgraded the DAQ driver from the latest to version 6.9.3 - still with only the aforementioned two selectable ranges. 

What else shall I try? Thank you for any help. 

[Chris_W.]

Hi krmt,

What exactly do you mean when you say you can only choose between +-10V and 0-10V for the input range? Are you using a Traditional DAQ Test Panel? Or are you trying to set these values in the properties for this device? You should be able to change these values in the Test Panel by setting changing your upper and lower bounds.

The AT-MIO-64E-3 has 15 selectable ranges based on the expected voltage level of the signal you are reading in and the gain that is chosen. In the User Manual on pages 33-34/184 it explains that the full range of the board is 10V and that can be used in two different polarities, Unipolar and Bipolar. This simply means that when using the entire input voltage range you can have a range of either 0-10V, or ± 5V.

In LabVIEW you can change the bounds of your input signals using either the AI Config.vi or the AI Hardware Config.vi. These should be your expected voltage range of input signals. These vi’s then adjust the hardware gain to amplify that range to fit the full 10V range of your card, so that it can utilize the full resolution of your ADC.  In the Hardware Config.vi, you can also manually set the values of polarity, gain and range.

The ranges shown in table 3-2 on page 34/184 are just ranges that will be used with the available gains to amplify your specified input range to fill the 10V of the ADC. For example, if you specified your input range to be 0 – 3V the driver would coerce that range to be 0 – 5V and would amplify it by 2. I hope this helps.

Chris N White
High Speed Products Group

[krmt]

Hi Chris,

indeed, i mixed things up: i was expecting a pull down menu from which i could select my desired input range.Setting up a virtual channel, I noticed that one can set a specific range and the driver coerce the next highest one (as you explained it with 3V using the 5V-range)

Since I do not use Labview to read the card's channels, I'm interested if it is possible to configure the card with a little software tool, so that I am able to set my desired input range.  I didn't find any source code example doing so. I use a proprietary software which is capable of reading some NI DAQ cards, however, setting the input range has not been implemented.

Thank you very much for your help.

[Chris_W.]

Hi krmt,

For Traditional DAQ devices we do not have a standalone configuration tool. What type of software are you using? Would you be able to incorporate a C function dll? If you can, there is a C function for the Traditional DAQ driver DLL that is called AI_Configure that allows you to set the expected input range. You would have to load the nidaq32.dll in your environment and then you could use AI_Configure. Take a look at the Traditional NI-DAQ (Legacy) C Function Reference Help that can be found in Start>>Programs>>National Instruments>>NI-DAQ>>Traditional NI-DAQ Function Reference Help. This will show you all available C functions for Traditional DAQ. 

Chris N White
High Speed Products Group

Message Edited by Chris W. on 11-04-2008 02:26 PM