MPXV7025GC6U vacuum sensor port connection

[evacuate]

The sensor has 2 ports P1 and P2.

The data sheet states that P1 should always be greater than P2.

The package that I have has a port on P1 and P2 is just an orifice.

I need to measure vacuum in a container with this sensor.

Would it be correct to mount the sensor inside the container so that the port P1 faces atmosphere and P2 towards vacuum?

[TomasVaverka]

Hi Vishal,

The MPXV7000 series of integrated pressure sensors is designed to measure both the positive and negative pressure with the offset hovering at Vs/2 (typically 2.5V). As they are bidirectional, there is no need to swap hoses when switching from intake to exhaust.

The MPXV7025GC6U is a gauge pressure sensor with a hole on the side (P2) of the device, so it measures with reference to the ambient barometric pressure. If you want to measure a pressure that is not influenced by changes in atmospheric pressure (e.g. leak testing a completely sealed container), you should use an absolute pressure sensor. If a gauge pressure sensor was used instead to measure the container pressure and the barometric pressure changed, then the sensor’s reading would change, despite the fact that the pressure in the container remains the same.

Let me know if you need more information or if you have any other questions.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.

[evacuate]

Hello Tomas,

Thanks for the brief, it indeed was quiet helpful.

The MPXV7025GC6U that I have has a hole and a port.

As per the datasheet the port is P1 and hole is P2.

Also datasheet says that P1 > P2 that is P1 should always be greater than P2.

Now suppose I have 2 containers and I want to measure vacuum in the first container and pressure in the second container.

If I follow the rule that P1 > P2

In the first container I have the hole in vacuum and port facing the atmospheric pressure.

In the second container I have the port in the pressurized side and hole facing the atmospheric pressure.

Now in both cases since P1 > P2 it is a positive differential and hence I am getting only voltages in the range 2.5V (0 kPa) to 4.75V (25 kPa).

In case 1 increasing vacuum will cause P2 to be lesser than P1 and hence P1 > P2 and

In case 2 increasing pressure will cause P1 > P2

Now the question is how do I get the sensor to sense negative differential so that I get 0.25V(-25 kPa) to 2.5V(0 kPa) range?

Can I give the sensor P2 > P1 will it damage the sensor?

Do I really need to change the sensor orientation as I have done in the above to cases or can the same orientation be used for both?

[TomasVaverka · Accepted solution]

Hi Vishal,

Sorry for the delay in getting back to you, but I have been on holiday the last couple of days.

As I wrote before, the MPXV7000 series (including the MPXV7025GC6U) is capable of measuring a pressure that alternates from positive to negative.The output voltage is below Vs/2 if P1<P2 and the sensor will not be damaged as long as the maximum pressure (200kPa) is not exceeded.

Regards,

Tomas