The wind speed and direction meter is a large-scale intelligent wind speed sensing and alarming equipment specially developed for various large-scale machinery and equipment, which adopts an advanced microprocessor as the control core internally and advanced digital communication technology peripherally.The system has high stability, strong anti-interference ability, high detection accuracy, the wind cup is made of special material with high mechanical strength and strong wind resistance, the display chassis is novel and unique in design, sturdy and durable, easy to install and use.All electrical interfaces are in accordance with international standards.Wind speed and wind direction meter is composed of wind speed and wind direction monitoring instrument, wind speed sensor, wind direction sensor and connecting cable, which is easy to install and free of debugging.With the advantages of advanced technology, high measurement accuracy, large data capacity, long telemetry distance, friendly man-machine interface and high reliability, the wind speed and wind direction meter is widely used in the fields of meteorology, ocean, environment, airports, harbors, industry and agriculture, as well as transportation.
Test Methods
This method tests the change in resistance of the sensor when it is cooled by wind in the energized state, and thus tests the wind speed.Wind direction information cannot be obtained.In addition to being easy and convenient to carry, it has a high cost/performance ratio and is widely used as a standard product for anemometers.Thermal anemometers use platinum wires, thermocouples, and semiconductors, but we use platinum coiled wires.Platinum wire is the most materially stable material.As a result, long-term stability, as well as in temperature compensation, are advantageous.
Make up
The wind speed and direction meter wind speed measurement part adopts microcomputer technology, which can simultaneously measure instantaneous wind speed, instantaneous wind level average wind speed, average wind level and corresponding wave height parameters.It has data locking function, which is easy to read.The wind direction part is equipped with automatic north pointing device, which simplifies the measurement operation as there is no need for manual north pointing during the measurement.This instrument is a precision instrument, equipped with a high-grade aluminum alloy portable case (shape: 300*200*160), which provides good protection for the instrument and is easy to carry.This instrument is small in size, light in weight, full-featured, and can be widely used in agriculture, forestry, environmental protection, marine, scientific research and other fields to measure the wind parameters of the atmosphere.
1, wind direction part: by the wind vane, wind direction disk (magnetic compass) and other components, the wind direction value by the wind direction pointer in the position of the wind direction disk to determine.
2, wind speed part: the traditional three-ring rotating frame structure, the instrument within the microcontroller on the wind speed sensor output frequency sampling, calculation, and finally the instrument output instantaneous wind speed, one-minute average wind speed, instantaneous wind level, one-minute average wind level, average wind speed and the corresponding wave height.
The measured parameters are directly displayed on the liquid crystal display with numbers.
1, wind speed technical indicators measurement range 0 ~ 30m / s starting wind speed 0.8m / s measurement accuracy ± (0.3 + 0.03v) m / s (v indication of wind speed) wind speed parameters instantaneous wind speed, average wind speed, instantaneous wind level, the average wind level, and its corresponding wave height display resolution of 0.1m / s (wind speed) 1 (wind level) 0.1m (wave height)
2, the wind direction technical indicators measurement range of 0 to360 degrees, 16 azimuth starting wind speed 1.0m/s measurement accuracy ± 1/2 azimuth wind direction fixed north automatically
3, the working environment temperature -10 ~ 45 ° C humidity ≦ 100% RH (non-condensing)
4, the power supply 3V (3.4 ~ 2.68V) No. 5 batteries 2 5, size and weight dimensions of 410 x 100x100 cubic millimeters weight of 0.5kg technical specifications Item wind speedSensor Wind direction sensor
Accuracy ± (0.3+0.03V) m/s ±6° (± 3°)
Starting wind speed ≤0.5m/s ≤0.5m/s
Output form Square wave 6-bit (7-bit) code (or voltage)
Operating voltage 5V ~ 12V 5V ~ 12V
Operating current 10mA 20mA (or 2 ~ 3mA)
Operating environment Temperature -60 ℃ ~ 50 ℃ Humidity ≤100%RH Temperature -60 ℃ ~ 50 ℃Humidity ≤100%RH
The sensing element of the wind speed sensor is a three-cup wind assembly, consisting of three carbon fiber wind cups and cup holders.The transducer is a multi-tooth rotating cup and slit optocoupler.When the wind cup is rotated by the horizontal wind force, a signal of frequency is output through the rotation of the shaft rotary cup in the slit optocoupler.
The wind direction sensor's transducer is a code disk and photoelectric assembly.When the wind vane rotates with the wind direction, the rotation of the code disk in the gap of the photoelectric assembly is driven by the shaft.The resulting photoelectric signal corresponds to a Gray code output of the prevailing wind direction.A precision conductive plastic potentiometer may be used for the sensor's transducer, thus producing a variable voltage signal output at the active end of the potentiometer.
Working Principle
It is based on the fact that a cold impinging airflow carries away the heat from the thermal element, with the help of a regulating switch that keeps the temperature constant, then the regulating current is proportional to the flow rate.When using a thermal probe in turbulent flow, air currents from all directions impinge on the thermal element at the same time, thus affecting the accuracy of the measurement results.When measuring in turbulent flow, the thermal anemometer flow rate sensor tends to show higher values than the rotating wheel probe.The above phenomenon can be observed during duct measurements.Depending on the different designs for managing turbulence in ducts, they can occur even at low speeds.Therefore, the anemometer measurement process should be carried out in a straight part of the pipe.The starting point of the straight section shall be at least 10 x D (D = diameter of the pipe in CM) away in front of the measurement point; the end point shall be at least 4 x D after the measurement point.The fluid section shall not be obstructed in any way.(corners, heavy overhangs, objects, etc.)
Rotating Wheel Probes for Anemometers
The working principle of the anemometer's rotating wheel probe is based on the conversion of the rotation into an electrical signal, which is first passed through a proximity inductor, which "counts" the rotation of the wheel and generates a series of pulses, which are then converted and processed by the detector to obtain the value of the rotational speed.The large diameter probes (60mm, 100mm) of the anemometer are suitable for the measurement of turbulent flows (e.g. at the outlet of a pipeline) with small or medium flow velocities.The small diameter probes of the anemometers are more suitable for measuring airflow in ducts with a cross-section more than 100 times the cross-sectional area of the probe.
Positioning of anemometers in the air stream
The correct adjustment position for the rotating probe of the anemometer is with the airflow direction parallel to the rotor axis.When the probe is gently rotated in the air stream, the value will change.When the reading reaches its maximum value, the probe is in the correct measuring position.When measuring in a pipe, the distance from the beginning of the straight part of the pipe to the measurement point should be greater than 0XD, turbulence on the anemometer's thermal probe and the Pitot tube has a relatively small effect.
Anemometers for airflow measurement in ducts
The 16mm probe of the anemometer has proven to be the most versatile.Its size ensures good permeability and is able to withstand flow velocities up to 60 m/s. Measurement of air flow velocity in ducts as one of the feasible measurement methods, the indirect measurement protocol (grid measurement method) applies to air measurement.
The following gauges are available:
Square-section gate, measuring common specifications
Circular-section gate, measuring center-axis specifications
Circular-section gate, measuring range-linear specifications
Anemometer Measurements in Pumped Exhaust Air
The air vents significantly change the relatively balanced distribution of the air flow in the duct: high velocity zones are generated on the surface of the free air vents, the rest of the duct is characterized by low velocity zones and vortices are generated on the grille.Depending on the design of the grille, the cross-section of the airflow is more stable at a certain distance in front of the grille (approx. 20 cm).In this case, measurements are usually made with a large aperture rotor of the anemometer.This is because the larger aperture enables the averaging of uneven flow velocities and the calculation of their average over a wide range.
The anemometer uses a volumetric flow funnel at the extraction hole for measurements:
Even if there is no grid interference at the extraction, the route of the air flow has no direction and its airflow cross-section is extremely inhomogeneous.The reason for this is that the local vacuum in the piping draws air out of the air chamber in a funnel shape, and there is no location that meets the measurement conditions for measurement operations even in an area that is very close to the pumped air.If measurements are made using the gate measurement method with an average value calculation function, and measurements are made using the volumetric flow rate determination method, and volumetric flow rate is determined, etc., only the pipe or funnel measurement method can provide reproducible measurement results.In this case, measurement funnels of different sizes are available to meet the requirements for use.Using the measuring funnel it is possible to generate a fixed cross-section that meets the conditions for flow rate measurement at a certain distance in front of the lamella valve. Measurements are made to locate the center of this cross-section and fix the cross-section.The measured value obtained by the flow rate probe is multiplied by the funnel coefficient to calculate the volume flow rate pumped.(e.g. funnel factor 20)
The photoelectric wind sensor uses a low inertia light metal wind vane to respond to the wind direction and drive the coaxial code disk to rotate, which is encoded in Gray code and scanned by optoelectronics to output an electrical signal corresponding to the wind direction.
The wind speed sensor of photoelectric type adopts low inertia wind cup, rotating with the wind, driving the coaxial truncated disk to rotate, outputting the pulse string by photoelectronic scanning, and outputting the corresponding value of pulse frequency corresponding to the number of revolutions, which is convenient for collection and processing.It has high strength, good starting, and conforms to the national meteorological measurement standard;
The wind direction sensor has a built-in electronic compass, which automatically locates the direction angle, and can be installed in fixed places as well as in mobile places (such as special vehicles, ships, drilling platforms, etc.);
Appliance
Velocity and turbulence measurements of low-speed flows with hot-wire or hot-film probes;
Pedagogical demonstrations: e.g. demonstration of typical fluid dynamic phenomena;
Multi-point measurements, e.g. for the study of boundary layers and continuous structures.
Features of the miniature thermostatic hot-wire anemometer:
Easy to operate;
Small size;
Battery operated;
Ideal for field measurements;
Can be built into models;
Special application versions for other hot-wire and hot-film probes are available.
Miniature Thermostatic Hot-Wire Anemometer Introduction:
The Miniature Thermostatic Hot-Wire Anemometer is a general purpose anemometer for DANTEC gas hot-wire and hot-film probes.
It is based on the conventional thermostatic hot-wire anemometer and is designed, in terms of its technical specifications and performance, for ordinary low velocity flows occurring in many fluid dynamics applications.It is primarily intended for the measurement of flow velocity and turbulence in moderate-frequency flow fields, and is particularly suited for instructional purposes, multipoint measurements, and field measurements.
Miniature thermostatic hot-wire anemometer Description:
It is available in single and multi-channel (up to 3 CTA lines) versions.It is connected via a BNC port connector and operates from a 12V DC power adapter or battery.Its bandwidth is optimized for use with hot-wire probes (up to 10kHz), but good operating performance can also be obtained with hot-film probes. The MiniCTA allows the use of probes with a maximum cold impedance of 10Ω.Its superheat ratio setting is defined by a jumper switch inside the box.
The settings for the superheat ratio can be found in the EXCEL file on the floppy disk supplied with the manual.
Extension of 2D and 3D systems:
The 3-channel instrument cassettes with 2 or 3 MiniCTA boards can be used with probe arrays for 2- or 3-dimensional fluid measurements.The cassettes are connected to the probes via 3 BNC connectors and have an additional auxiliary BNC connector for the input of an external sensor.
Multi-Channel Thermostatic Hot-Wire Anemometer - Effective Depiction of Flow Fields Using Hot-Wire Probes
Multi-channel thermostatic hot-wire anemometer applications:
Depiction of velocity and turbulence distributions in gases;
Measurements of continuous structures using probe arrays;
Depiction of turbulence points as well as interstitial flows in edge-layer flow fields;
Flow field measurements
Multi-channel thermostatic hot-wire anemometer features:
Simultaneous measurement of up to 16 points;
Measurement of one-, two-, and three-dimensional fluids;
Factory hardware setup is directly usable;
Recording of offset temperatures by means of the system temperature probe;
Multi-probe calibration by means of a built-in standard velocity sensor (optional)
Introduction to multi-channel thermostatic hot-wire anemometers:
Multi-channel thermostatic hot-wire anemometers provide an effective and viable solution for the characterization of velocity and turbulence distributions in low- and medium-speed airflows at frequencies up to 10kHz.The multi-channel concept derives from the use of probe arrays for measurements, which reduces experimental time and lowers the cost of running expensive wind tunnels.The manufacturer's hardware is set up to make user-friendly and simple operation.A standard speed sensor as an option can be used to calibrate multiple probes.
The multi-channel thermostatic hot-wire anemometer is supported by an application software package for operation.
Multi-Channel Thermostatic Hot-Wire Anemometer Description:
The multi-channel thermostatic hot-wire anemometer is divided into eight
The CTA channel is mounted in a mainframe with probe inputs and multi-pin outputs adapted to NI A/D boards.The mainframe is powered by either a power adapter or a 12V battery.Two mainframes can be connected together to form a 16-channel system.
The 6-channel version is additionally equipped with a temperature channel to record the ambient temperature at the time of measurement using the system temperature probe.This version can also be extended with a standard velocity sensor for multi-probe calibration in experimental conditions such as wind tunnels.
The instantly available concept in the manufacturer's default settings:
The system can be used directly with standard hot-wire probes without the need for user-adjusted settings.The overheat impedance of the hot-wire probes is normally handled by the factory with the available settings.The overheat ratio may vary slightly from probe to probe in practice, so the settings allow the user to adjust the settings according to the actual probe being used.
The probe is connected to the BNC connector on the rear panel of the main unit via a standard 4m or 10m probe cable.The status indicator and the work/wait switch are on the front panel and also have a BNC connector for monitoring.
The output signals are fed directly to the A/D board in the PC via a transmission cable without the need for a separate junction box.
