Problem reading analog input

[odsnot]

Good day all,

I'm using NI-7350 controller to measure voltage from a power supply. 

I connected the positive line to Analog input 1 (Pin32) and Gnd to Analog Input ground (Pin68)

But I am reading a analog value of 18000 for 5V and the value goes up and down propotional to the voltage set. Is it a value setting problem ? Since the station I'm using doesn't have internet acess, I took a screenshot of the vi instead. Thanks

[odsnot]

Sorry I messed up with the screenshot. This one any better ?

[Napoleon_Buonaparte]

Hi Odsnot,

Motion control's analog input returns binary, and you need to translate it mannualy.
Refer to range.png, if you use 0-10V range, you can build a vi as shown in translate.png to read analog to translate voltage.

Regards, Kate

[odsnot]

Thanks for the reply,

I've managed to read the voltage reading, had to change the constant 10 to a 5 though.

However for example 8+V, the reading shows 8.73156E+9. How do i convert it to like maybe 8.7 because my meter isn't responding to the voltage which i think the E+9 is the cause.

[AHK]

Hi, Just decrease the Digits of Precission of your indicator. This slove your query.

regards

Akshath 

[tbd]

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akshath wrote:

Hi, Just decrease the Digits of Precission of your indicator. This slove your query.

regards

Akshath 

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I think Odsnot has used an odd scaling factor - 8,731.56 mega-volts seems a bit high(?) 

[odsnot]

What is the odd scaling factor ? I dont remember using it..

I tired dividing 8.73156E+9 by a million and I got the voltage I wanted lol.

[tbd]

Hi odsnot,

      According to the table provided by Napoleon, in no case should a raw return value be greater than 65535, and the results of proper scaling will be a smaller [absolute value] than the raw values.

Using that table, and assuming a -10 to +10 Range is used, the return value of 18000 (see original post) is scaled as follows ScaledValue = (10*18000/32768) = 5.5 V.  So that seems to work.

I don't understand where 8731560 (8.73156 +E9) comes from - it doesn't seem possible(?)

Cheers.