pressure

"i converted 0-5 analog volatge to 0-5 digital voltage"

What do you mean by that?
What is a "digital voltage"?

"now i want convert digital data to pressure"

Then you need to know the relationship between your sensor's output and the measured pressure:
If it's linear, this is simply a matter of scaling (plus, perhaps, an offset);
If it's non-linear, a lookup table is probably easiest.

"my output should be like this

0v 1.1E-1 3v 4.1E-4
0.1 1.2E-1 4v 5.1E-5
1v 2.1E-2 5v 6.1E-6
2v 3.1E-3"

I have no idea what that's supposed to mean - please explain!

"i want 500 values in between 0 to 5 volts"

So, you have a range of 5V in 500 steps;
therefore the step size is simply one-fivehundredth of 5V;
ie, step size = 5V/500 = 0.01V

"how to calibrate the voltage interms of preesure"

Apply known pressures across the range of interest, and measure the corresponding voltages!

"my C51 not taking floting oparations"

Of course not - it's the evaluation version!

Instead of using 0.01V, just think of it as 10mV (or whatever) - then there's no decimals required!

"i converted 0-5 analog volatge to 0-5 digital voltage"

What do you mean by that?
What is a "digital voltage"?

"now i want convert digital data to pressure"

Then you need to know the relationship between your sensor's output and the measured pressure:
If it's linear, this is simply a matter of scaling (plus, perhaps, an offset);
If it's non-linear, a lookup table is probably easiest.

"my output should be like this

0v 1.1E-1 3v 4.1E-4
0.1 1.2E-1 4v 5.1E-5
1v 2.1E-2 5v 6.1E-6
2v 3.1E-3"

I have no idea what that's supposed to mean - please explain!

"i want 500 values in between 0 to 5 volts"

So, you have a range of 5V in 500 steps;
therefore the step size is simply one-fivehundredth of 5V;
ie, step size = 5V/500 = 0.01V

"how to calibrate the voltage interms of preesure"

Apply known pressures across the range of interest, and measure the corresponding voltages!

"my C51 not taking floting oparations"

Of course not - it's the evaluation version!

Instead of using 0.01V, just think of it as 10mV (or whatever) - then there's no decimals required!

thank you sir


sir here my preesure sensor output is 0-5v caresponding pressure is
0.00v=1.1E-1
5.00v=6.1E-6
now i want scale the intermediate values

example
voltage pressure

0.00v =1.1E-1
0.01v =1.2E-1
0.02v =1.3E-1
.
.
1.00 =2.1E-2
.
.
2.00 =3.1E-3
.
.
3.00 =4.1E-4
4.00 =5.1E-4
5.00 =6.1E-5

This is the data
the relation between pressure and voltage is non-linear
I did't have any relation. I have only above data.

thanks

What are the units of pressure here?

The data shows that your sensor gives a higher voltage output for a lower pressure - is that right?


"I did't have any relation. I have only above data."

Surely, that data is the relationship!
Just use it as a lookup table!

hi sir
"The data shows that your sensor gives a higher voltage output for a lower pressure - is that right?"
yes sir

it well gives a higher voltage output for a lower pressure.
thes values iam taken from standard chart.
now i want convert this chart to application.

if you do't mind how to use the look up table for 500 values.
Here iam using c51 evalutionn vertion
pleace give one example.

pleace sir

You still haven't said what unit of pressure you're using - bar? atmosphere? mm of water? mm of mercury? Pascal?

"how to use the look up table for 500 values."

The number of values merely dictates the size of the table.

Here's a brief overview of how to use a lookup table to implement a mathematical function:

http://www.8052.com/forum/read.phtml?id=22213