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how to test for BP20..??


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There is information on testing all of our sensors in the Knowlegebase section of the NRG Systems website:


Here is what it says about BP-20:

Testing a BP-20 pressure sensor

Tools Required:

  • 7 V DC to 35 V DC source (12 V nominal, battery recommended)
  • Digital Voltmeter (DVM) set to 20 V DC scale




  • Disconnect BP-20 from logger
  • Connect DC supply (-) to black wire
  • Connect DC supply (+) to red wire
  • Set DVM to 20 V DC scale
  • Connect DVM (-) to black wire
  • Connect DVM (+) to white wire (Note: older units have a both a green wire and white wire.  In this case, use the green wire.)
  • Measure and record output voltage on white wire (typically near 4 Volts)...
  • To determine the absolute pressure as reported by the BP-20 use the following:


kPa = (21.79 x Vout) + 10.55


Perfomance Comparison:

  • Check this value against the logger display to confirm scale is correct.

  • Check this value against another barometer to confirm reading is correct.

  • Note: BP-20 should draw about 8 mA of current



  • BP-20 voltage output is measured to be 4.123 V DC...
  • kPa = (21.79 X 4.123) + 10.55
  • kPa = 100.4
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Does the voltage change, or remain constant?

10 V corresponds to a barometric pressure reading of 228 kPa. This is not a realistic reading for anywhere on the surface of Earth.

Check to be sure the weep holes on either side of the cable strain relief are not plugged; they should be free for air to flow in and out. You can check this with a pin or paper clip.

If the weep holes are clear and the sensor maintains unreasonably high pressure readings, it may be that the sensor is damaged.

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