Industry new

Electromagnetic flowmeters will be described under the environmental factors

In general, the flowmeter is subject to external interference when it is measured, which affects the measurement results. This article describes what external interference is involved in the measurement of the electromagnetic flowmeter. List it out so that everyone can understand the existence of these factors and hope to help everyone.

Electromagnetic flowmeters are susceptible to external interference due to small flow signals. The main sources of interference are pipeline stray currents, static electricity, electromagnetic waves and magnetic fields.

● Pipe stray current:

Mainly rely on electromagnetic flowmeter good grounding protection, usually the grounding resistance should be less than 100Q, do not share grounding with other motors and electrical appliances. Sometimes the environmental conditions are good, the plug-in electromagnetic flowmeter can work normally without grounding, but we think that it is better to do so. Because once the good environmental conditions no longer exist, the instrument will malfunction, which will affect the use at that time, and then make various checks and bring a lot of trouble. Sometimes the plug-in electromagnetic flowmeter is well grounded. Because the stray current of the pipeline is too strong (such as the electrolytic process pipeline and the cathodic protection pipeline network) to affect the normal measurement of the electromagnetic flow juice, the electromagnetic flow sensor must be used between the electromagnetic flow sensor and the pipeline. Electrical insulation isolation.

● Static electricity and electromagnetic interference:

Static electricity and electromagnetic waves are introduced through the signal line between the plug-in electromagnetic flowmeter sensor and the converter. Generally, good shielding (such as shielding cables for signal wires and cables placed inside the protective iron pipe) can be prevented. However, there have been instances where the prevention of strong electromagnetic waves is ineffective. At this time, the converter is moved closer to the sensor, the connected signal cable is shortened, or an integrated meter without an external cable is used.

● Magnetic field interference:

Usually only the electromagnetic flow sensor is taken away from the strong magnetic field source. The ability of the plug-in electromagnetic flowmeter to resist magnetic fields varies depending on the structural design of the sensor. For example, the protective coil of the sensor is made of non-magnetic materials (such as aluminum and plastic), which has weaker resistance to magnetic fields and stronger steel.

PREVIOUS：Electromagnetic flowmeter sensing signal weakNEXT：Description of electromagnetic flowmeter perf