Electromagnetic flowmeter features
Using intelligent judgment, the measurement correction setting is not used, and the air traffic control alarm and electrode detection application are more convenient;
Advanced "rough error handling" technology, which can remove fluids such as slurry to measure sharp disturbances, reduce output runout, maintain high precision measurement and make output more stable;
With a fluid density setting, it can display mass flow;
Constant current excitation current range, 125mA, 250mA optional, can be used with different manufacturers, different types of electromagnetic flow sensors;
Control function with remote reset of the totalizer, with contact signal input for starting and stopping accumulation, suitable for total inspection and batch processing applications;
With self-test and self-diagnosis function;
Advanced non-volatile memory for higher circuit reliability and effective protection of setup and measurement parameters;
The meter can be equipped with an unpowered clock and memory for recording the power down time, power-on time and power-down time;
The meter has an optional hour recording function that can store flow and electrode resistance measurements for more than 30 days.
The new keyboard processing method avoids the keyboard operation affecting the measurement, and can enter and return the operation menu to make the parameter setting more convenient;
The total display uses 10-bit decimal 9999999999 full-value carry, which solves the practice of double-word full value 4294967285 (hexadecimal FFFF) carry-in habit;
With wireless transmission, the mesh network is organized by the wireless HART protocol.
To ensure the measurement accuracy of the electromagnetic flowmeter, proper installation is very important.
1. The transmitter should be installed in a dry and ventilated place indoors. Avoid installation in places where the ambient temperature is too high, should not be subject to strong vibration, try to avoid equipment with strong magnetic fields, such as large motors, transformers, etc. Avoid installation in corrosive gases. The installation location is easy to overhaul. This is the environmental condition to ensure the normal operation of the transmitter.
2. In order to ensure that the measuring tube of the transmitter is filled with the measured medium, the stacker is preferably installed vertically, and the flow direction is from bottom to top. Especially for liquid-solid two-phase flow, it must be installed vertically. If the site is only allowed to be installed horizontally, it must be ensured that the two electrodes are at the same level.
3. The transmitter should be equipped with valves and bypass at both ends.
4. The millivolt AC potential measured by the electrode of the electromagnetic flow transmitter is based on the liquid potential in the transmitter. In order to stabilize the liquid potential and maintain the potential of the transmitter and fluid to ensure stable measurement, the transmitter shell and the metal tube should have good grounding at both ends, and the converter housing should also be grounded. The grounding resistance should not be greater than 10 and cannot be shared with the grounding wire of other electrical equipment. If the transmitter housing is not guaranteed to be in good contact with the metal pipe, connect them with metal wires. Re-reliable grounding.
5. In order to avoid interference signals, the signal between the transmitter and the converter must be transmitted with shielded wires. It is not allowed to place the signal cable and power cable in parallel in the same cable. The length of the signal cable should generally not exceed 30 m.
6. converter installation site should avoid AC and DC strong magnetic field and vibration, ambient temperature is -20 to 50 ° C, does not contain corrosive gases, relative humidity is not more than 80%.
7. In order to avoid the influence of the flow rate on the relative measurement, the flow regulating valve should be placed downstream of the transmitter. For small-caliber transmitters, since the distance from the center of the electrode to the inlet end of the flowmeter is equivalent to several times the length of the diameter D, the upstream straight pipe may not be specified. However, for a flowmeter with a large diameter, generally there should be a straight pipe section of 5D or more in the upstream, and the downstream pipe section is generally not required.
Pressure and temperature selection
The actual working pressure of the fluid in the pipeline should be less than the rated working pressure of the flowmeter. Pay attention to whether there is negative pressure in the pipeline, such as the evaporation process, and the negative pressure is up to -60KPa. Such working conditions should be communicated with the manufacturer's technicians when ordering. Strict requirements are imposed on the lining material. The actual temperature should meet the temperature requirements specified by the flowmeter.
Power supply selection
The choice of the electromagnetic flowmeter power supply should be selected according to the flowmeter itself and the environment of the site. If the site allows, the power supply is convenient, safe and easy to maintain. As a chemical company, more than 90% of the raw materials and process links are in the liquid phase. During operation, the internal humidity of the workshop is large, and no flammable gas is generated during the whole operation. It is safer to use DC24V for power supply. Outdoor dry environment, choose AC220V power supply, convenient lead wire, good maintenance and low cost.
Some explosion-proof occasions, such as flowmeters used in gas boilers, are ideal for battery-powered electromagnetic flowmeters.