Shanghai Chenzhu Instrument CO., LTD.
Shanghai Chenzhu Instrument CO., LTD.

Precautions for Installing Isolation Intrinsic Safe Barriers

Oct 17 , 2022

The isolation intrinsic safety barrier is a device that is used in intrinsically safe explosion-proof systems to safely isolate field instruments. For explosion-proof systems and explosion-proof electrical equipment, intrinsic safe barriers are used in the design of intrinsically safe explosion-proof systems.

The intrinsic safe barrier is a device installed in a safe place and contains intrinsically safe circuits and non-intrinsically safe circuits. The current and voltage limiting circuits in the circuit limit the energy sent to the intrinsically safe circuit on site, thereby preventing the dangerous energy of the non-intrinsically safe circuit from entering the intrinsically safe circuit.

It is called associated equipment in the intrinsically safe explosion-proof system and is an important part of the intrinsically safe system. The intrinsic safe barrier is installed in a safe place, receives signals from dangerous areas, and outputs safety signals to safe or dangerous areas.

Ⅰ. Precautions for installation of intrinsic safe barriers

1. The intrinsic safe barrier should be installed in a safe place, and the environmental conditions meet the requirements of "use conditions" in the "Intrinsic Safety Barrier Selection Sample".

2. The connection wires of the intrinsically safe end (blue end) and the non-intrinsically safe end circuit of the isolation intrinsic safety barrier should be laid separately in the sink line, and each should use an independent protective sleeve. No other power cables, including those used for intrinsically safe circuits, are allowed in the wiring conduit on the side of the intrinsic safe barrier.

3. The wire leading to the dangerous place should choose the intrinsically safe wire with blue mark, the soft copper area of the wire must be greater than 0.5㎟, and the insulation strength should be greater than 500V.

4. Before energizing and debugging the intrinsic safe barrier, it is necessary to pay attention to whether the model, wiring method, line polarity, etc. of the isolated barrier meet the requirements in the design and product requirements, otherwise it may cause harm to people and equipment.

5. It is strictly forbidden to use a megohmmeter to test the insulation strength between the terminals of the intrinsic safe barrier. If you want to check the insulation strength of the system, you should disconnect all the wiring of the intrinsic safe barrier, otherwise the internal circuit of the intrinsic safe barrier may be damaged.

6. Before programming the isolation intrinsic safety barrier on site, all wiring must be disconnected and then connected to the programmer, and then power on for programming, otherwise it may cause adverse consequences.


Ⅱ. Selection and application of intrinsic safe barriers

1. What does the intrinsic safe barrier mainly rely on to prevent explosion?

The isolated barriers for hazardous areas have attracted more and more attention, and the intrinsic safety barriers as their main components will also be recognized by people. So, what does the intrinsic safety barrier mainly rely on to prevent explosion?

Controlling energy is the magic weapon for explosion-proof of intrinsic safe barriers. Whether it is Zener intrinsically-safety barrier or isolated barrier, the requirements of explosion-proof regulations are achieved by controlling energy.

2. What should be paid attention to when using intrinsic safe barriers?

Pay attention to the capacitive reactance and inductive reactance of cables and field devices. Intrinsically safe explosion-proof means that the system is explosion-proof. In addition to the required explosion-proof level required by the intrinsic safety barrier, the energy storage of cables and field devices is also a key issue.

Especially after parametric certification replaces system certification, engineers need to pay special attention to this problem.

First, pay attention to intrinsically safe grounding, Zener intrinsic safe barriers require intrinsically safe grounding.

Second, the intrinsically safe cables and non-intrinsically safe cables should be laid in different trunkings separately, and should be clearly marked.

Third, you should pay attention to the power failure when replacing.

3. Should isolation intrinsic safety barriers or Zener intrinsic safety barriers be used?

Generally speaking, the selection of Zener intrinsic safe barriers is relatively easy, not easy to be damaged, and there are fewer changes to the structure of the original system, and the advantages are more obvious. In addition, the Zener intrinsic safe barrier will not affect the accuracy of the original signal because there is no signal transition.

The isolation intrinsic safety barrier like gs8500 is based on high frequency, and the signal is modulated and demodulated. If the signal changes, the accuracy will be affected by the intrinsic safety barrier circuit.

But the isolation intrinsic safe barrier does not require intrinsically safe grounding, which is where it is superior to the Zener intrinsic safe barrier.