Non Linear 0-10V Sensor

Hello Experts!

I use a 0-10V vacuum sensor. (using logo analog input AM2 module).

But every sensor I've seen so far had a Linear graph. So I could use them by "Analog Amplifier" block.

But This one is not linear and has an exponential/logarithmic manner.

The relationship between "air pressure " and the output "voltage" of the sensor is as follow:

Voltage = 10^{(Pressure - 5.5)}

[The Corresponding graph image is attached]

How can I calculate the pressure using the voltage input?

I know Logo can calculate linear formulas using "Gain" and "Offset" in "Analog Amplifier" block, but what about sensors like this?

Thanks guys...

Hello Mohsenm;

To set things up properly, I have to say I am not an expert on Logo!

So first, here is a discussion on the forum considering ways to handle non-linear sensors of S7 CPUs; please take the time to look at proposed solutions:

https://support.industry.siemens.com/tf/ww/en/posts/nonlinear-scalling-for-analog-signal/77215?page=0&pageSize=10

Of course the mentioned CPUs of the S7 family have more available memory and a larger instruction set than the Logo!.

The only alternative I have found in Logo! is the look-up table technique, and here is a thread discussing the issue:

https://support.industry.siemens.com/tf/fr/en/posts/lookup-table-in-fbd/164869/?page=0&pageSize=10

Hope this helps,

Daniel Chartier