Y-Scale for I16 Data Type

[Biomedical Signal Processing]

Hi,
I am using analog DAQ to aquire +/-1V and streaming to binary file on HDD. I am using I16 representation with analog input ranges set to +/-5 Volts. My Y-scale on chart shows data range between +400 and -400 counts. I could not understand how it represents data from +-1V to +-400 range? I tried using SGL data type and it shows correct Y-scale range of +-1 Volts. Any suggestion how Labview converts data to I16 format?

Also, I am trying to format X-sclae and Y-scale, but some time it automatically changes upper and lower ranges of scale, minor gride divsions etc, any suggestions for customising grids and scale i.e. I need five grid divisions for every major divison on both X and Y scale. I am using simple chart.

I appreciate your eff
orts to reply my questions,

Thanks,

Kishor

[waldemar.hersacher]

Hi Kishor,

1.
I think you have done the following: On AI Read.vi you have selected the type binary array. This will give the samples in I16. This I16 number is the number the A/D converter generates. This number will always be between -2028 and 2047 for 12 bit cards. You have to convert this number to a real voltage by yourself. Changing the type to scaled array you will get SGL. This value is scaled according to the settings in MAX for your channel. If you didn't configure any channels in MAX the range is always the range you used for the card.

2.
To avoid flipping of the scale and changing the grid divisions right click on the scale and uncheck "AutoScale". Unfortunatly you have no exact control how much divisions were generated.

Waldemar