user23741: Are there any oxygen sensors that measure up to 50%?.
As I understand, there are sensors that measure only in range 0-30%.
Is it possible to increase the threshold of sensitivity of the sensor?

user28033: You can try SO002 or DS-TR250.    

Is it possible to increase the threshold of sensitivity of the sensor?    

I don't think its possible. Perhaps you can tweak the reading sensitivity, but since the sensor are mostly analog, it's not possible. And maybe that also the reason the 2 sensors I've mentioned above have several series based on their measuring threshold.

23741: <p>Are there any oxygen sensors that measure up to 50%?.</p>

<p>As I understand, there are sensors that measure only in range 0-30%.</p>

<p>Is it possible to increase the threshold of sensitivity of the sensor?</p>
 28033: <p>You can try <a href="http://www.sensore-electronic.com/wp-content/uploads/2016/04/SO002e-3_Data-sheet-sensor.pdf" rel="nofollow noreferrer">SO002</a> or <a href="http://www.co2meters.com/Documentation/Datasheets/DS-TR250Z-sensor.pdf" rel="nofollow noreferrer">DS-TR250</a>.    </p>

<blockquote>
  <p>Is it possible to increase the threshold of sensitivity of the sensor?    </p>
</blockquote>

<p>I don't think its possible. Perhaps you can tweak the reading sensitivity, but since the sensor are mostly analog, it's not possible. And maybe that also the reason the 2 sensors I've mentioned above have several series based on their measuring threshold.</p>
