Setting up the MPX2010DP differential pressure transducer

[david_fowler]

Hello,

         I am having issues with setting up my MPX2010DP pressure transducer.  I have it hooked up to a pitot tube, which takes pressure measurements from inside of a duct.  The transducer output is wired to an NI 9215 +/- 10V analog input module.  This module records the data, and this data is processed using a Labview VI that I wrote. 

          The transducer has 4 pins.  1: Ground, 2: V+out, 3: Vsupply (I'm using 12 volts from a power supply), 4: V-out.  The V+out and V-out are wired to the NI 9215 analog input module.  The pin 1 ground is wired to the COM of the 9215 module which is wired to the power supply ground.  the Vsupply is wired to the 12V power supply.

Problem)   I can't seem to get the setup right.  Whether it be wiring, proper supply voltage, or something.  Using a voltmeter, I seemed to get voltages that didn't correspond to any pressure fluctuations; it was acting as a voltage divider.

Solution)   The output range of the transducer is 0-25mV.  Does this call for signal conditioning or amplification?  Use an op-amp that has a gain of 400 so I can achieve a 10V output range?  

Question)   What am I doing wrong?  I thought I would simply supply a voltage and read the outputs with an analog input, but it has turned out to be difficult.  Am I over-analyzing my issue?

Thanks!

David 

[reyes]

Hi David,

All 4 pins of the MPX2010DP needs to be connected as below:

Pin 1: GND

Pin 2: Positive Output Voltage

Pin 3: Voltage Supply (10V recommended)

Pin 4: Negative Output Voltage

The output of this sensor is differential compensated, which means that the sensor gives you a differential output in the range of millivolts (output is already internally temperature compensated), you need to externally add the amplification circuit before sending the sensor’s output signal to the MCU’s ADC.

In the Application note AN1318 you can find some examples about how to interface the differential output of the pressure sensor to the mcu:

http://www.nxp.com/assets/documents/data/en/application-notes/AN1318.pdf

Now, I would recommend you to use an integrated pressure sensor instead, this kind of pressure sensors are already internally compensated, calibrated and amplified, so you do not need many external components other than few capacitors (as can be seen in Figure 3 of the MPX5010 datasheet) and the output is already given in the range of 0 to 5V (as can be seen in Figure 4 of the MPX5010 datasheet), so it is much more easier to use than the MPX2010DP pressure sensor.

An example for integrated low pressure range sensor is the MPX5010 family, you can find the device datasheet in the following link: https://www.nxp.com/docs/en/data-sheet/MPX5010.pdf

Regards,

Jose