Basics of
Vaccum Pressure Sensor Calibration:
- A pressure sensor is a device that changes pressure into an
electrical signal. That electrical signal is only useful if it
accurately represents the pressure applied to the sensor.
Calibration is the process by which the sensor electrical signal is
adjusted so that it has a known relationship to the applied
pressure. After calibration the electrical signal can be measured
and that can be used to determine the pressure at the sensor.
- The electronics that support pressure sensors are called
carrier demodulators. These connect to the transducer and – once
calibrated – provide a DC signal that will be proportional to the
pressure at the transducer. The different models of pressure
sensors are DP15 Range Changeable Pressure Sensor, DP45 Low
Pressure Differential Pressure Sensor, DP103 Very Low Pressure
Sensor or DP360 High Line Pressure Sensor.
- Typical carrier demodulators for these sensors are CD15 Carrier
Demodulator, CD17 USB Carrier Demodulator, CD23 Signal Conditioning
with LED Display, CD280 Multi-Channel Carrier Demodulator or CD379
Portable Carrier Demodulator.
- Note that the calibration is done as a system – transducer,
cable and electronics together. We are often asked, but cannot
provide, calibrated sensors. The calibration must be done with the
transducer and electronics connected together.
Calibration adjustments for sensors involve two parameters:
zero and span. These adjustments are located on
the carrier demodulator.
- For the CD15 carrier demodulator, for example, the zero
adjustment sets the output signal to 0 Vdc when the pressure
applied to the sensor is 0.
- The span adjustment is used to set the output signal to +10 Vdc
when the full scale pressure is applied to the sensor. The 10 VDC
output signal is read with a voltmeter connected to the front-panel
binding posts.
The following are the sequence of steps for callibration of
Vaccum pressure sensor.
- Connect Voltmeter to the output terminals of the carrier
demodulator
- With zero pressure applied to the transducer, turn the Zero
adjustment until the voltmeter reads 0 Vdc
- Apply full scale pressure to the sensor.
- Turn the Span adjustment until the output at the voltmeter
reads +10 Vdc.
- Bleed out the pressure and check the zero pressure reading
again – adjust to 0 Vdc as needed.
Tolerances on the voltmeter readings are typically +/-0.005
Vdc.
The following image shows simple setup for callibration of
pressure sensor.
Here in the image i used CD15 carrier demodulator and DP15
sensor