Plug-in ultrasonic flowmeter features
Programmable frequency low frequency rectangular wave excitation improves stability of flow measurement and low power loss;
Using 16-bit embedded microprocessor, the operation speed is fast and the precision is high;
Full digital processing, strong anti-interference ability, reliable measurement, high precision, flow measurement range up to 100:1;
Ultra-low EMI switching power supply, suitable for wide range of power supply voltage and good anti-EMC performance;
Full Chinese character menu operation, easy to use, easy to operate, easy to learn and understand;
High definition backlit LCD display;
It has two-way flow measurement and two-way total accumulation function, and the current and frequency have bidirectional output function;
There are three totalizers in the internal to display the forward cumulative amount, the reverse cumulative amount and the difference integrated amount;
With RS485 or RS232 digital communication signal output
It has a conductivity measurement function to determine whether the sensor is empty or not;
The constant current excitation current range is large, and can be used with different companies and different types of electromagnetic flow sensors;
With self-test and self-diagnosis function;
High reliability with SMD devices and surface mount (SMT) technology;
The internal design of the meter has a power-down clock that can record 16 power-down times.
Some experiences on using ultrasonic flowmeter
1. The flowmeter has two modes, diagonal and reflective. When the reflection mode is not detected, it can be measured in diagonal mode, so that we have been using the reflection mode.
2. The flowmeter requires a relatively high pipe, and the insulation layer must be scraped off, otherwise it cannot be measured. When we measured the air conditioning water system, we cut the insulation layer with a knife to prevent the sensor. After the measurement, the cut insulation layer was glued. The surface of the pipe should be as bright as possible. If it is too rough, it must be sanded.
3. It is difficult to measure when the fluid in the pipeline is not full, so the measuring position should be as straight as possible, away from elbows, valves and other places.
4. The authenticity of the flowmeter reading depends on the signal strength. When the signal is too low, the result is basically unreliable, generally more than 60% or even more.
5. Since the readings may vary greatly, the approach we take is to have the flowmeter read continuously, such as continuously recording one minute of reading and then taking the average.
6. Measuring hot water lines is more difficult than cold water lines. Because the wall temperature of the hot water pipe is high, the coupling agent is easily formed at a high temperature. In addition to the product's own coupling agent, we have tried toothpaste.
The summary of ultrasonic flowmeter measurement accuracy and accuracy needs to be improved.
Turbine Flowmeter Product Introduction
A flow meter that uses a turbine for measurement. It first converts the flow rate to the speed of the turbine and then converts the speed into an electrical signal proportional to the flow. This flow meter is used to detect instantaneous flow and total integrated flow, and its output signal is frequency, which is easy to digitize. In the figure, the induction coil and the permanent magnet are fixed together on the casing. When the ferromagnetic turbine blade passes the magnet, the magnetic resistance of the magnetic circuit changes to generate an induced signal. The signal is amplified and shaped by an amplifier and sent to a counter or frequency meter to display the total integrated flow. At the same time, the pulse frequency is frequency-voltage converted to indicate the instantaneous flow rate. The speed of the impeller is proportional to the flow rate, and the number of revolutions of the impeller is proportional to the total amount flowing. The output of the turbine flow meter is a frequency modulated signal that not only improves the immunity of the detection circuit, but also simplifies the flow detection system. It has a turndown ratio of 10:1 and an accuracy of ±0.2%. Turbine flowmeters with small inertia and small size have a time constant of 0.01 seconds.
Turbine flowmeter is the main type of velocity flowmeter. When the fluid to be measured flows through the turbine flowmeter sensor, under the action of the fluid, the impeller is forced to rotate, and its rotational speed is proportional to the average flow velocity of the pipeline. At the same time, the blade periodicity The magnetic flux generated by the electromagnet is cut and the magnetic flux of the coil is changed. According to the principle of electromagnetic induction, a pulsating potential signal, that is, an electric pulse signal, is generated in the coil, and the frequency of the electric pulsation signal is proportional to the flow rate of the fluid to be measured.