Hi,
I have a pressure transducer (m3041-000006-250pg) with an already amplified output signal of 1-5V over the pressure range of 250psi. (data sheet attached) I need help converting the analog input to the corresponding pressure. The analog output is not proportional to the supply voltage. Can anyone help me?

2305678.pdf (340 KB)

Datasheet only shows some linear relations between sensor output and pressure/temperature. No mention about non-linearity of the output, or formulas on how to calculate it. So it seems simply a linear relation.

Why do you think it's not linear? And if not linear, what's the relationship between the two?

Thanks for the fast reply. Assuming a linear relationship, would the conversion from volts to psi be something like this:
float pressure = (250.0/4.0)
(voltage-1);

This is the part I'm not sure about.

Looks like - unfortunately the datasheet doesn't explicitly provide this info.

What is the ADC result at 0 PSI? Lets say 103, at 200 (full scale)? Lets say 900, Zero = 103, span = 900 - 103 = 797. If you read 500 on ADC, pressure = 500 - Zero = 397 / span = 0.498 * full scale = 99.6 PSI.
So, pressure = (ADC - Zero) / span * full_scale.
No need to convert to Volts, unless you want to know.
BTW: I didn't see that part #, are you sure of those numbers?

Thank you, that’s the most intuitive way of doing it and similar to mapping the values. I’ll try it out later. To use this method I would have to assume that the full scale ADC output would be 1024 because I can’t determine that experimentally (equipment limitation). Or I could use whatever upper limit I can reach experimentally. Also, the lower limit may be negative due to the accuracy of the sensor, I seen this using the other method… I will compare the methods to see

The part number is missing from the manual, here’s the supplier link:

http://uk.farnell.com/sensor-solutions-te-connectivity/m3041-000006-250pg/pressure-sensor-250psi-1-8-27/dp/2717585?ost=2717585&iscrfnonsku=false&ddkey=http%3Aen-GB%2FElement14_United_Kingdom%2Fsearch

When I worked on industrial equipment I didn't take the datasheet at it's word, usually the sensors I specified had a max range at least 50% more than the expected max pressure in the system, I calibrated them like I showed you, at 0 and normal max pressure, not what the datasheet said should be max reading. And then checked at 25, 50 and 75%.