H
2
S 0.1 0.5
NO
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0.5
1.0
Cl
2
0.1 0.3
Data within less than 30 minutes every day are considered into the one-week average and maximum..
EMI
Various interference sources, from either outside or inside the equipment or application system, affect the system in the
conductive ways such as capacitive coupling, inductive coupling, and electromagnetic radiation.
There are two types of electromagnetic interference: radiated interference and conducted interference, depending on the
type of the transmission path.
When the energy, often RF energy, from a component arrives at a sensitive component via the space, the energy is
known as radiated interference. The interference source can be either a part of the interfered system or a completely
electrically isolated unit. Conducted interference results from the electromagnetic wire or signal cable connection between
the source and the sensitive component, along which cable the interference conducts from one unit to another. Conducted
interference often affects the power supply of the equipment, but can be controlled by a filter. Radiated interference may
affect any signal path in the equipment and is difficult to shield.
Effective measures should be taken for the power system to prevent the interference from the electric grid.
The working ground of the switch should be preferably separated and kept as far as possible from the grounding
device of the power equipment or the anti-lightning grounding device.
Keep the equipment away from high-power radio transmitter, radar transmitting station, and high-frequency
large-current device.
Measures must be taken to shield static electricity.
During applications, the switch may be subject to external interference that affect the device through conduction manners
such as capacitance coupling, inductive coupling, electromagnetic wave emission, common impedance (including
grounding systems), and wires (power cables, signal cables and outgoing transmission cables). For that purpose, note
that:
For the AC power supply system TN, single-phase three-core power socket with protective earthing conductors (PE)
should be adopted to effectively filter out interference from the power grid through the filtering circuit.
The switch should be located at places free from large power radio launch pad, radar launch pad, and
high-frequency large-current devices.
If necessary, electromagnetic shielding should be adopted. For example, use interface cables to shield cables.
Interface cables should be laid inside the equipment room. Outdoor cabling is prohibited, avoiding damages to
device signal interfaces caused by over-voltage or over-current of lightning.
