How to use pressure sensor (Honeywell NBPMLNN060PGUNV)

Question

I have acquired a 0-60psi pressure sensor, namely the NBPMLNN060PGUNV (nr. 2146011 from Farnell).

According to the datasheet sensitivity of the device should typically be 21mV/V/Full range. Essentially I figured that I would be able to get a ~100mV output

difference from the device - if connected to a 5V supply - measured between pins 2 and 4 (21mV * 5V = 105mV).

But when I connect the sensor to the supply, the output voltage is only 4mV, and decreasing when I increase the pressure.

When output voltage reaches 0, nothing else happens even if I increase the pressure further. Needless to say, this behaviour seems a bit peculiar to me.

Can anyone verify if this behaviour is correct? Because sensing on a voltage of only 4mV or less is rather difficult in my application.

For testing purposes, if I up the supply voltage to 10V, the output voltage also doubles (~9mV). But it is still a very small voltage difference to work with.

Am I doing something wrong or do I need to add a differential amplifier circuit to get higher voltage differences?

Thank you for your time.

Regards,

David Larsen

AKJ Inventions ApS.

michaelkellett · Accepted Answer

I was wondering if you had mis-identified the pins but if you did I would expect the offset to be about 1/3 of the excitation voltage. What is the voltage between the output pins and ground ? (I expect 1/2 the excitation voltage). I wonder if you just have a faulty sensor ? MK

vsluiter · Answer

Have you tried what it does when you make vacuum? Does the voltage go up then? Any chance the voltage goes up with decreasing pressure? Just a thought, I hope others have more useful hints / tips.