Technical parameters of several commonly used flow meters

Technical parameters Measurement variable: flow rate. Input variable measurement range: typical vu003d0.10m/s with specified measurement accuracy. Operable flow range: more than 1000:1. Input signal state input (auxiliary input): Uu003d330vDC, Riu003d5k, electrical isolation. Configurable: reset of accumulated quantity (S), suppression of measured value, reset of error information. Current input (only when Promag53): active technical parameter 　　 measured variable: flow rate. Input variable measurement range: typical vu003d0.1……10m/s with specified measurement accuracy. Operable flow range: more than 1000:1. Input signal state input (auxiliary input): Uu003d3…30vDC, Riu003d5kΩ, electrical isolation . Configurable: reset of accumulated quantity (S), suppression of measured value, reset of error information. Current input (only when Promag53): active/passive optional, electrical isolation resolution: 2μA active: 4. . . 20mA, Ri≤150Ω, Uoutu003d24VDC, anti-current short circuit 　　 passive: 0/4. . . 20mA, Ri≤150Ω, Umaxu003d30VDC. Output variable output signal current output: active/passive optional, electrical isolation, time constant optional (0.05...100s), full-scale value optional, temperature coefficient: typical 0.005%or/℃; resolution: 0.5 μA　　active: 0/4...20mA, RL<700Ω(HART:RL≥250Ω)　　passive: 4...20mA,max.30VDC, Ri≤150Ω　　pulse/frequency output:　　passive, open collector 30VDC , 250mA, electrical isolation. Frequency output: full-scale frequency 2...1000Hz (fmaxu003d1250Hz), open/close ratio 1:1 　 　 pulse width: maximum 10s. Pulse output: pulse value and pulse polarity optional, maximum pulse The width can be set (0.05...2s), the maximum pulse frequency is optional. Material transmitter housing, integrated housing: powder-coated cast aluminum; wall-mounted housing: cast aluminum sensor housing, DN25...300: spray Powder coated cast aluminum; DN350...2000: Coated steel model specification: 50W9H-UD0A1AK2C4AW (DN900), 50W is the 50 series; 9H means the caliber is 900mm (DN900); U means the substrate material is polyurethane ; D means process connection/material is PN10DIN250l, ST37-2 flange (applicable to DN200-DN2000); 0 means electrode material (all electrodes) is 1.4435/316L stainless steel; A means calibration is 0.5%. 3-point calibration; 1 description The certification does not require special certification; the second A means no anti-riot requirements; K means that the enclosure protection is IP68, separate type, wall-mounted; 2 means that the separated type comes with a 10m cable; 　　 environmental conditions: ambient temperature -20...+ 60°C (sensor, transmitter), install in a dark place, avoid direct sunlight, especially in warm climate areas. Measurement accuracy reference conditions: in line with DIN19200 and VDI/VDE264l, medium temperature: +28℃±k, ambient temperature: +22℃±k, preheating time: 30 minutes, 　　 should pay attention to the installation, only when the tube is full can be accurate Avoid the following installation positions: 　　installation at the highest point of the pipeline (easy to collect bubbles)　　 directly before the open outlet of a downward pipeline.　　Be careful not to install a flow tube on the inlet side of the pump to avoid damage to the lining of the flow tube caused by pumping pressure. When using a reciprocating, diaphragm or plunger pump, it is necessary to install a pulse throttle valve.　　 When the length of the downward pipeline exceeds 5m, install a siphon or a vent valve behind the sensor. In order to avoid possible damage to the lining of the measuring tube caused by low pressure. Ensure that the pipe is full and reduce the gas content.　　Installation position: The most suitable position can help avoid the accumulation of gas and the accumulation of residue in the measuring tube.　　 Vertical installation; this orientation is ideal for easy self-emptying pipeline systems, and it is possible to not add an empty tube detection electrode.　　Horizontal installation: The measuring electrode plane must be level, which can prevent short-term insulation of the electrode due to entrained air bubbles. Note: The empty pipe detection function can only work correctly when the measuring device is installed horizontally and the transmitter housing is upward. If the vibration is very severe, the sensor and transmitter should be installed separately.　　 Base, support: If the nominal diameter is DN ≥ 350, install the transmitter on a base that can withstand sufficient load. Note that it is not allowed to use the outer frame to support the weight of the sensor. This deforms the outer frame and destroys the internal excitation coil. If possible, it is best to avoid components such as valves, tees, elbows, etc. when installing sensors. Ensure the following required inlet and outlet straight pipe sections to ensure measurement accuracy: inlet length>10×DN outlet length>5×DN sensor and transmitter grounding The sensor is grounded at the center of the pipeline: the sensor and the medium must have the same potential for use Ensure measurement accuracy and avoid electrode corrosion damage. Equipotentiality is ensured by installing a ground reference electrode in the sensor. If the medium flows in an unlined and grounded metal pipe, it can meet the grounding requirements by connecting to the transmitter housing. Same as above for separate grounding.　　 Note: If you are not sure whether the media ground is properly grounded or not, you should install a grounding ring.　　Fault diagnosis: 　　Electromagnetic flowmeter 　　If there is a failure after startup or during operation, the fault diagnosis is usually carried out according to the following checklist to directly find the cause of the problem and the corresponding solution