I want to measure /- 62.5 pascal from MPXV7002DP sensor. How can i accomplish that with good repeatability ?

[zeeshannoorwala]

I want to measure  +/- 62.5 pascal (+/- 0.25 inch H2O) from MPXV7002DP sensor. How can i accomplish that with good repeatability ?

From what i see in the datasheet, it gives 2500mV at 0 pascal, and +/- 1mV per pascal on the positive or negative side.

I am assuming to follow these steps :

1) Using a Differential amplifier, subtract 2437.5 mV from the output signal of MPVX7002DP, this will result in 0mV at -62.5 pascal differential pressure - AND also result in 125 mV at +62.5 pascal Diff. Pressure.

and then,

2) Add a gain stage of x24, so the resultant max 125mV will become 3000mV, which is the upper range of my  ADC.

However, my problems are :

A) Is this the right approach ?

B) how do i generate a precise reference of 2437.5 mV for the differential amplifier ?

C) The graph of output voltage from the sensor shows different slopes at different temperatures. How do i accomodate for this in my design ?

Thanks for your help.

[Monitair]

Hi - I would also be interested in the NPS30 devices. I have used about 15000 MVPV7002DP units over the last 7 years, but I am finding it difficult to source now that ventilators are in such high demand. My product, which is used in the industrial safety field, depends on the ability to measure down from -100Pa. I would dearly love to fit a gauge sensor capable of negative pressures, but I have not found one yet. Also I2C would be preferable to analog and associated signal conditioning. 

[franklatona-r49]

Hello, reviewing the datasheet for the MPXV7002DP, the typical sensitivity is ± 2.5% full scale span equating to ±100 Pa which is larger than ± 62.5 Pa required.  We will however, have a digital differential pressure sensor (NPS30 family) available for sampling later this year that will meet your requirements.  MCU based software examples will also be available for several different Freedom MCU boards at Sensor Toolbox: Sensor Development Ecosystem|NXP . Please contact our regional sales team for additional information.

[zeeshannoorwala]

Hello. Thank you Frank for the insight and new product offering.

We were in the process of finalizing our product design, which includes the MPXV7002DP for very low D.P. measurement, along with other sensing, control and logging systems.

As we would have it, we do have some time on hand for doing actual tests on prototypes, before locking everything down.

Would it be possible for you guys to share with us the Datasheet(s) and any application notes for the indicated NPS30 series of sensors, possibly with footprint and 3D model data, so we could in the mean time, design test prototype PCBAs ? By the time that's done, your new NPS30 would be available (hopefully), so perhaps we could sample a few and test on the new prototypes to finalize the electrical and mechanical design of our product, and plan productions accordingly  ?

You might understand, that the firmware will be finalized on the actual prototypes as well, so having the soft data (datasheets, app notes and PCB library footprint / 3d step files, etc.) early on would help us finalize our product design faster and reduce our go-to-market time.

Thanks.