Tag Archives: Sensirion

Low Pressure Drop Digital Flow Meters

Sensirion offers low-pressure drop digital flowmeters that are highly accurate and update the readings very fast. These meters are available in fully calibrated form along with built-in temperature compensation.

The SFM3000 sensor is a digital flow meter that Sensirion has designed for applications with high volumes of flow. The flow meter allows measuring with superb accuracy the flow rate of air, oxygen, or other non-aggressive gases. Sensirion has designed the flow channel in a special way so that introduction of the flow meter into a flow system results in a very low-pressure drop. These characteristics of the SFM3000 make it extremely suitable for use in applications that are very demanding, such as in respiratory and medical ventilation systems.

Operating the SFM3000 is very easy, as the flow meter operates off a 5 VDC supply voltage. It also features a 2-wire digital I2C interface for connecting with the controller. Sensirion has designed the flow meter such that it automatically linearizes and temperature compensates all measurement results internally.

A CMOSens sensor technology, patented by Sensirion, is the basis of the outstanding performance of the sensor. They have combined the sensor element, signal processing electronics, and digital calibration within a single microchip. A thermal sensor element measures the flow rate of the gas, and this also ensures that the signal processing is done at a high speed. The innovative measuring technique also makes it possible to make bidirectional measurements, while offering the best-in-class accuracy.

The CMOS technology is well-proven and is a perfectly suited method for high-quality mass production of the SFM3000 flow meter in a demanding and cost-sensitive market. Sensirion offers a variety of custom options for implementing the flow meter for high-volume OEM applications. They offer options like different body form factor, calibration for other gases, custom flow rates, and many more.

Applications of the SFM3000 low-pressure drop digital flow meter include laboratory use, environment monitoring, spectroscopy, fuel cell control, burner control, process automation, and medical use.

Sensirion has used a silicon sensor chip SF05 of the fifth generation in the design of the SFM3000 flow meter. It also has a sensor element to detect the flow of thermal mass. In addition to the two above, there is an amplifier, an analog to digital converter, read-only memory, digital circuitry for signal processing, and the digital I2C interface. Sensirion has achieved significant cost benefits and performance achievements with the seamless integration of the circuitry for acquiring the signal and processing it on a single silicon die.

Users can solder the SFM3000 sensor using standard selective soldering systems. However, they must not use reflow soldering as it may damage the sensor. During soldering, the user must protect the sensor ports from solder splash and flux. As the characteristics of machines for selective soldering may vary, the user must test the soldering arrangement before production use.

For soldering, Sensirion provides the mask drawing of the sensor for a reliable PCB attachment. For a sturdy integration of the sensor, the user must consider using the screw holes of the SFM3000. The fittings of the sensor correspond to the international standard ISO5356-1:2004.

Smart Sensors from Sensirion

Sensirion is offering three smart sensors that make it easy for electronic system designers to incorporate them into their applications. These are the AMT4x Smart Gadget, the SCD30 Sensor Module, and the STC31 Thermal Conductivity Sensor for CO2.

As a simple circuit board for a reference design, the AMT4x Smart Gadget from Sensirion is a demonstration kit for the SHT4x temperature and humidity sensors. The gadget displays information for temperature and humidity on an LCD screen. The built-in BLE or Bluetooth Low Energy module allows communication with smartphones and other Bluetooth-enabled devices.

The kit for the Smart Gadget includes an SHT40 sensor for temperature and humidity, a liquid crystal display, a push button, a Bluetooth MCU module, batteries, and other supports. Sensirion also provides detailed resources for the hardware design and information for an app download.

The Smart Gadget offers designers a simple reference design along with a circuit board. They can use it for measuring temperature and humidity while displaying it on an LCD, The MyAmbiance app for iOS and Android phones enables remote access and export capabilities along with data logging.

To sense CO2, Sensirion is offering their SCD30 Sensor Module. SCD30 uses the NDIR sensor technology for sensing CO2. It also has an integrated humidity and temperature sensor. The sensor measures the humidity and temperature in the ambient atmosphere while monitoring and compensating for external heat sources, without using any additional components. The height of the sensor module is low, and this allows easy integration in systems for various applications. The SCD30 achieves high accuracy and superior stability with its dual-channel capability.

The SCD30 sensor, with its NDIR CO2 sensor technology, and integrated humidity and temperature sensor, offers outstanding stability owing to the compensation from long-term drifts provided by its dual-channel capability. The sensor has a small form factor of 35 x 23 x 7 mm. Its measurement range covers 400 to 10,000 ppm, with an accuracy of ±30 ppm +3%. Apart from measuring the absolute concentration of carbon dioxide, the sensor can also measure temperature and relative humidity.

Applications of the SCD30 sensor include IoT devices, Smart Homes, Air purifiers, Air conditioners, HVAC equipment, and demand-controlled ventilation systems.

Sensirion also offers the STC31, a thermal conductivity sensor for the detection and measurement of Carbon dioxide. The gas concentration sensor is chip-sized, offers 16-bit resolution for high range, and is accurate for high volume production CO2 measurement.

Sensirion has based the sensor on an innovative principle of thermal conductivity measurement, which results in long-term stability and superb repeatability. With a digital I2C interface, the STC31 sensor can directly interface with a microprocessor. Working from a voltage ranging from 2.7 to 5 VDC, and a 5 mA maximum current rating, the STC31 sensor operates ideally from batteries while delivering top performance at minimal power budgets.

The STC31 is RoHS and REACH compliant, and its measurement range covers 20 to +85 °C. At a measurement rate of 1 reading per minute, the sensor consumes only 15 µW of power. With a track record of above 15 years, the STC31 sensor is an industry-proven technology.

Differential Pressure with a Tiny Sensor

Process control requires system operators to monitor and control the condition and movement of liquids and gases. Several instruments are available for this, allowing measurement and monitoring of variables, and these fall under the categories of pressure, temperature, level, and flow. Among the pressure-gage category, differential-pressure gages receive the widest recognition for being the largest specialty type – useful in filtration, flow, and level measurements.

While standard pressure gages measure pressure at a single point in a system, differential pressure gages measure pressures at two points and display the difference on a single dial. This makes it easy for the operator to know at a glance, which of the two points is at a higher pressure, and by how much. Use of differential pressure gages greatly reduces operator error, protecting expensive equipment. They reduce operator training and maintenance time, thereby improving process efficiency.

For instance, differential pressure gages are popularly applied in filtration. In this process, a filter separates unwanted contaminants or particles from a gas or liquid system. However, with the progress of the process, the filter becomes increasingly clogged, leading to a drop in efficiency and pressure at the outlet.

It would seem enough to use a single standard pressure gage at the outlet to monitor the health of the filter and assess the time for its inspection and replacement. However, the situation is complicated, as most processes do not maintain a steady working pressure. Several factors are responsible for this, such as compressor or pump on-off cycles or valve open-close cycles, causing wide pressure fluctuations in most processes. For many systems, operators expect such fluctuations of pressure as normal, within limits.

Using two standard pressure gages, one at the input and the other at the output, introduces two additional problems for the operator. First, this compounds the accuracy errors resulting from the two gages as against error from one gage. Second, the operator needs training in reading the two gages, then subtracting the readings, and finally, interpreting the result. History shows many operators do not truly understand the importance of the calculation.

Installing one differential pressure gage using the same taps at the filter inlet and outlet solves all the problems listed above. The accuracy goes up as the rate of error drops. Additionally, the operator does not have to rely on mathematics to understand and interpret the reading – most differential pressure gage dials feature a red arc to indicate the clogging of the filter.

The SDP3x differential pressure sensor from Sensirion is a tiny device. Its dimensions are only 5x8x5 mm, making it one of the smallest of its kind, but with countless new possibilities of applications. It is well suited for use in portable medical devices as well as in consumer electronics.

Users can choose between an analog signal output and a digital one from two versions of the fully calibrated and temperature-compensated differential pressure sensor. The digital sensor, the SDP31, comes with an I2C interface, while the analog sensor, the SDP36, offers an analog output signal. The sensors have a sampling rate of 2 KHz with a resolution of 16-bits, and a measurement range of +/-500 Pa with a span accuracy of 3% of the reading.

Digital Temperature Sensor with High Accuracy

Whether it is the body temperature, room temperature or the average temperature of the day, we take important decisions based on the various temperatures we measure and record. Although the mercury-based thermometer is still the most commonly used instrument, industrial temperature measurement has largely shifted to electronic sensors, data logging and digital displays. Accuracy in measurement is highly desirable and sensor manufacturers are constantly improving on their products offering better quality.

Sensirion is one of the world’s leading manufacturers of temperature and humidity sensors. Their new digital temperature sensor STS3x offers high accuracy. The tiny eight-pin DFN package of the STS3x is 0.9 mm high and measures only 2.5 x 2.5 mm across. Sensirion has based the STS3x on the same chip as their existing SHT3x humidity sensor. Because of its tiny size and wide range of supply voltage – 2.4 to 5.5 V – users can integrate the STS3x in a large variety of applications. The sensor is specifically suitable for battery-operated devices, as it consumes very low power – typically 6.6µW at 3.3V and one measurement per second. Nevertheless, it delivers outstanding performance, as it is remarkably accurate at +/-0.3°C, over an extensive temperature range spanning -40°C to +90°C.

Sensirion has based their temperature sensor STS3x on the industry-proven CMOSense technology. Compared to its predecessors, the STS3x has more intelligence, improved accuracy, and greater reliability. Added to this is the very fast start-up and response times of the STS3x, as well as enhanced functionality of high-speed signal processing and communication speeds of up to 1 MHz via two distinctive and user selectable I2C addresses.

Users of STS3x get a temperature sensor that comes pre-calibrated and offers a linearized, digital output, which is compensated for supply voltage instabilities. Sensirion has qualified the STS3x based on JESD 47, according to a dedicated automotive qualification plan certified by AEC Q100. Users have the choice of using the sensor as a watchdog, as it offers an alert option with definable set temperature points – strongly optimizing the overall power consumption. However demanding your data logger may be, and however complicated the temperature compensation of your application, the STS3x is an ideal solution.

Based on its high accuracy, the main target applications of the STS3x are the temperature calibrations in automotive components and body temperature measurement in wearable devices. Other applications that also benefit include a multitude of HVAC devices. This is because of the sensor’s highly accurate temperature data, resulting in precision, power savings, and reliability.

The automotive market benefits from the STS3x sensor solution because of its outstanding quality and low prices – automotive manufacturers can meet stringent emission standards of their industry. The STS3x offers new benchmarks in comfort, safety, and energy consumption. For instance, when combined with humidity sensors, the cabin air inside the vehicle can remain optimally regulated, using climate-controlled seats or air-conditioning. Moreover, by determining the dew point, the air-conditioning of the vehicle may be controlled to eliminate fogging of the windshields, thus ensuring a clear view of the road ahead.

Overall, the STS3x temperature sensors fulfill many stringent requirements of several applications considering cost-effectiveness, performance, and quality.