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A pressure transducer with a range +/-200Pa has both serial and analog outputs. I'm only interested in positive pressure besides sometimes the negative pressure needed to be measured when there is negative pressure offset. The pressure transducer DAC converts the serial to analog voltage output. And for some reason the voltage output needed to be used.

Currently the analog output is set to 0-10V and it means 0 to 200Pa pressure range corresponds to 0-10V voltage output range. But in this case sometimes negative pressure offset even small is outputted as zero volt which affects the measurements. This cane be seen in serial output but not analog output because the minimum is 0V for analog output. I dont want to track and zero this offset each time for automation reasons.

For a workaround I can set the range such that -200Pa to +200Pa will correspond to 0-10V and where in this case +5V to +10V will correspond to 0 to 200Pa.

I could only upload the manual here.

And here is main specs:

enter image description here

So to summarize currently the range 0 200Pa is mapped to 0 10V; but if I change the settings, it that case 0 200Pa will be mapped to +5V to +10V. In that case I can measure negative offset, but my confusion is how to quantify or expound on this change in terms of resolution.

0 200Pa was set to 10V change and now 0 200Pa will be set to 5V change. What does it change comparing to the previous matching in terms of precuson or resolution? Am I losing resolution here or anything else? What specs I need to focus on? Or do I need the analog output resolution?

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The datasheet parts you mention show the general accuracy of the sensor, and we can assume that this precision is available in the digital output. The data shown is not affected by the configuration of the analog output.

Alas, you do not show (and possibly you don't even have) resolution and precision specification of the analog output. The conversion from a digital value to the analog voltage is never perfect, and perhaps the resolution or accuracy of this conversion is it a limiting factor in your scenario. If that is indeed the case, you should expect to lose (up to) 50% of the resolution by doubling the pressure range. If the limiting factors lie elsewhere (like in the precision of the sensor itself), changing the analog output configuration does not significantly change the precision and resolution of your application.

To find out whether the DAC is limiting your precision, you do indeed need the detailed specifications of the analog output, just as you imply in your last question.

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  • \$\begingroup\$ In the first case 10V/200Pa I get 50mV/Pa in the second 5V/200Pa which is 25mV/Pa. And if I measure this with an ADC of 5mV resolution, in the first case I can measure down to 0.1Pa and in the second case down to 0.2Pa. Is my logic correct? (Im assuming the output resolution is smaller than ADC resolution) \$\endgroup\$ – user1999 Apr 23 '19 at 10:57
  • \$\begingroup\$ Yes. That's completely correct. If you are limited by the resolution of the ADC (or the DAC), any reduction of the voltage range emitted by the sensor directly reduces your resolution. But if you need the pressure in digital form and high resolution is important, you should really consider whether it is possible to just use the digital output of the sensor. \$\endgroup\$ – Michael Karcher Apr 23 '19 at 11:04

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