The safety grid limits the energy entering the site, i.e. limits the pressure and flow rate, so that the field lines will not spark in any state and will not cause an explosion. This explosion-proof method is called basic safety. Our common safety gate has Zener safety gate, transistor safety gate, transformer isolation safety gate, are the advantages of industrial production and helper.

Safety grid is a general term, divided into Zener safety grid and isolation safety grid, isolation safety grid referred to as isolation grid.

How the safety grid works

1. Working principle of signal isolator:

First, the signal of a transform transmitter or meter is modulated through a semiconductor component, then isolated for conversion through an optical or magnetic induction device, then demodulated for conversion back to the original signal before isolation, and the power source of the isolated signal is isolated. Ensure absolute independence between signal, power and ground.

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2. The working principle of Zener-type safety grid:

The main function of the safety grid is to limit the dangerous ability of the safe place to enter the dangerous place and limit the voltage and current sent to the dangerous place.

Zener tube Z is used to limit voltage. When the circuit voltage is close to the safe voltage limit, the Zener tube is switched on so that the voltage at both ends of the Zener tube is always kept below the safe limit. Resistance R is used to limit the current. When the voltage is limited, the resistance value should be selected appropriately, and the circuit current can be limited below the safe current limit.

The function of fuse F is to prevent the circuit voltage limit failure, because the Zener tube is blown by the high current flowing for a long time. When a voltage above the safe voltage limit is added to the circuit, the Zener tube passes. If there is no fuse, the current flowing through the Zener tube will rise indefinitely and eventually burn the Zener tube, making the bribe lose the voltage limit. To ensure the safety of the bridle limit, the fuse was blown ten times faster than the Zener tube could have been blown.

3. Isolation signal isolation safety grid working principle:

Compared with Zener safety gate, isolation safety gate not only has the function of voltage limiting and current limiting, but also has the function of current isolating. Isolation grid is usually composed of three parts: circuit energy limiting unit, current isolation unit and signal processing unit. Circuit energy limiting unit is the core part of safety gate. In addition, the bribery power supply circuit used to drive the field instrument and the detection circuit for instrument signal acquisition. The signal processing unit performs signal processing according to the functional requirements of the safety gate.

The role of the safety grid

Safety gate is an indispensable safety equipment in many industries. It mainly deals with or uses some flammable materials, such as crude oil and some crude derivatives, alcohol, natural gas, powder and so on. Any leakage or improper use of these items can become an explosive environment. For the safety of the factory and individuals, it is necessary to ensure that the working environment does not cause explosions. Safety barriers play a very important role in these protection processes,

The safety barrier is located between the control room and the equipment installed in the dangerous place, mainly to protect the function. Any electrical equipment may cause an explosion during the production process. All kinds of friction electric spark, static electricity, high temperature are inevitable in industrial production, so the safety grid provides protection measures for industrial production.

A very reliable grounding system must be in place during installation, and field instruments in hazardous areas must be isolated. Otherwise, signals cannot be correctly transmitted after grounding, affecting the stability of the system.