When MP3V5050GP was measuring a closed container, the output ADC had been slowly dropping

[xuximan]

Hello, we used MP3V5050GP in a small project to test the air tightness of the device, but we ran into problems. As follows: When MP3V5050GP is in direct contact with air, the output ADC occasionally fluctuates 1, but is very stable most of the time. However, we injected air at a certain pressure (say, 20Kpa) into the closed container and waited for it to stabilize for a period of time (say, 5 seconds later) to detect the pressure of the container. It was found that the output ADC had been slowly declining and was not stable.

[TomasVaverka]

Hello,

I am not sure what is the reason of this instability. There may be shifts due to temperature and aging as described in the AN1636, but it is not what is happening in your case. Also the response time is typically 1ms, so much shorter than your stabilization period. Can you please share more results of your experiments perhaps under various pressure?

Best regards,

Tomas

[xuximan]

OK.Below are data at two pressures, one for each second. The first one is 14KPa,the output AD drops by 1 at the 7th second, and then by 1 at the 14th second; it keeps dropping slowly, and I can't find the pattern. The second one is the case of 10KPa, and the data is quite stable this time. Finally, thank you for your reply.

[TomasVaverka]

Hello,

It is hard to identify the root cause if the behavior is different at these two pressure values. What kind of container are you using and is not it leaking at higher pressures? Is it dropping continuously at the higher pressure or does it stabilize at a certain value after some time?

Best regards,

Tomas

[xuximan]

The picture of the container is attached, theoretically this container can withstand pressure up to 30 Kpa. we use silicone plugs plugging the two ends, one end silicone connected to the tube, easy to test. Previously tried the case of 20Kpa, the drop is very obvious, this process is continuous. Although the theoretical pressure resistance value of the container is 30Kpa, but the actual use of 10Kpa test results are good, it may indeed not be suitable for use in high pressure situations.

Thank you.

[xuximan]

The output AD has been slowly declining, is it the sensor itself?