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Building Intelligence
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Pressure Sensor
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High resolution and high accuracy differential pressure sensor used for building science applications.
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Overview
General Description
The SDP1000-L025 differential pressure sensors for air covers -62Pa to +62Pa. The SDP1000 is mounted in a rugged housing and is equipped with a standard audio jack for easy usage with SMT data acquisition units.
The SDP1000 differential pressure sensor features a unique dynamic range, zero offset and unsurpassed long term stability. This makes it an ideal fit for mobile applications where it is used in different orientations.
Although the output of the differential pressure sensor is analog, the internal linearization and temperature compensation are performed digitally. This results in a superior accuracy, outstanding resolution (up to 0.05 Pa), and lowest temperature dependence.
Its leading performance is based on Sensirion’s proprietary CMOSens® sensor technology which combines the sensor element with amplification and A/D conversion on one single silicon chip. The differential pressure is measured by a thermal sensor element. In contrast to other thermal differential pressure sensors only a very small amount of air is required. This leads to a reliable operation even under harsh conditions. In comparison to membrane based sensors the SDP1000 differential pressure sensor show an extended measurement range, better offset stability and improved reproducibility even at low pressure ranges. In addition the SDP1000 is robust against pressure bursts and shows no sensitivity to the mounting orientation.
The Differential Pressure Sensor is based on a proprietary technology used to reduce output offset and common mode errors. Output offset errors due to change in temperature, warm-up instability, and position sensitivity are significantly reduced when compared to conventional compensation methods. The sensor uses a silicon, micro machined stress concentration enhanced structure to provide a very linear output to measured pressure.
Features
- ±62 Pa (±0.25 INCH H20) range
- Fully bidirectional calibration
- Fully calibrated and temperature compensated
- Excellent accuracy and reproducibility even below 10 Pa
- Not sensitive to mounting orientation
- SMT gateway facilitates zero offset and initialization
- Compatible with SMT WiDAQ and A2 data acquisition units
Typical Applications
- Building science research
- Air flow direction through building envelope
- Differential pressure tracking between building envelope and external air
- Environmental controls
- HVAC
Specs
Specifications
| Measurement Range | -62 Pa to +62 Pa |
| Power | 4.75 to 5.25V - Typical 5V |
| Full Scale Output | 4V at +62 Pa 0.2V at -62 Pa |
| Zero Pressure Output | 2.1V |
| Accuracy | 0.5% FS |
| Repeatability | 0.3% measured value |
| Offset stability | Max ±0.1 Pa/year |
| Additional error over temperature | 0.003 %FS/ºC |
| Resolution | 0.1 Pa |
| Admissible Overpressure | 1 bar |
| Burst Pressure Capability | 2 bars |
Environmental
| Media | Air |
| Operating temperature | -10°C to 60°C |
| Storage Temperature | -40°C to 80°C |
| Humidity Limits | 0% to 95% RH (non condensing) |
Specifications are subject to change without notice
Temperature Compensation
The differential pressure sensor features a sophisticated built-in temperature compensation circuit. The temperature is measured on the CMOSens chip by means of a PTAT bandgap reference temperature sensor. Its data is fed into a compensation circuit which is also integrated on the CMOSens® sensor chip. No external temperature compensation is required.
Altitude Correction
The differential pressure can be compensated by a correction factor according to the following equation:
Dpeff = Dpsensor * Pcal / Pamb
Dpeff is the effective differential pressure
Dpsensor is the pressure read by the sensor
Pcal / Pamb can be derived from the following table:
Mounting
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Use two sided tape or Velcro to secure sensor to surface. |
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Attach the hose securely over the port so that it has a tight fit. Route the hose from the Hi port to the area high-pressure area and the Lo port to the low-pressure area. This is a differential pressure sensor, therefore the difference in pressure will be recorded, if the Hi and Lo ports are interchanged the polarity will be opposite to what is expected. |
Hose extensions are not required if one side is already in the desired space.
Sensor hose lengths can be adjusted by cutting them with a scissors.
The recommended hose requires an inner diameter of 3.18 to 3.8mm)(1/8 to 3/20 inch). Due to the dynamic measurement principle, a small air flow is required which leads to a dependence on the length of the hose. Tubes up to 1m show less than 1% error of the measured value.
| Length of the connecting hose | Deviation of Measured Value |
| 0.5 m (20 inch) | -0.4% |
| 1.0 m (40 inch) | -0.8% |
| 2.0 m (80 inch) | -1.6% |
| 4.0 m (160 inch) | -3.2% |
Connectivity
Pressure sensor Connection to Audio Jacks
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Insert audio jack into AUX port on the Mobile WiDAQ. BiG Input 5.
Note: Mobile WiDAQs need to have the Internal RH sensor removed and 5V set to always ON. Contact SMT for details if you want to use this with your Mobile WiDAQ. |
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Insert audio jack into voltage port (inputs 3 and 4) on the SMT-A2 BiG Input 6. |
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No. |
Audio Jack |
Function |
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1 |
A (Red) |
+5V |
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2 |
B (Black) |
Pressure |
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3 |
C (Yellow) |
Thermistor |
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4 |
D (Green) |
Ground |
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5 |
NC |
Shield |
Pressure sensor to CAT5 Cable
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Pressure sensor wiring to Industrial WiDAQ 8 Channel Resistance, 2 Channel Voltage WiDAQ Only one pressure sensor can be used with this configuration. |
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WiDAQ Input |
CAT5 Cable |
Function |
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17-24 |
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Resistance |
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+ |
Blue |
+5V |
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GND |
White/Blue |
GND |
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V2 |
White/Orange |
No Connect |
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V1 |
White/Orange |
Pressure 1 |
8 Channel Voltage WiDAQ - 8 pressure sensors
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WiDAQ Input |
CAT5 Cable |
Function |
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17,19,21,23 |
Blue |
+5V |
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18,20,22,24 |
White/Orange |
Pressure X |
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GND |
White/Blue |
GND |
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SMT Research, LTD. | 200-75 W Broadway | Vancouver, BC | V5Y 1P1