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

Six Precautions for Safe Use of Intrinsically Safe Barriers

Jan 11 , 2023

The intrinsically safe barrier will transmit the voltage and current signals from the dangerous area to safe areas through isolation and transmission to output a single-channel or mutually independent dual-channel current/voltage signal. In addition, it can also be networked for serial communication in the secure area through the configured communication interface.

The intrinsically safe barrier is an intelligent intrinsic safe barrier product. Users can set an input signal type and output range for this product through a dedicated programmer or computer.

The intrinsic safety barrier adopts three isolation technologies of input, output and power supply to ensure the reliability. It adopts voltage limiting, current limiting, anti-surge and other methods for all signal terminals to protect the circuit. In addition, there are methods of combining electromagnetic isolation and photoelectric isolation of the intrinsically safe barrier, which ensure the physical separation between intrinsically safe and non-intrinsically safe ends and enhances product reliability.

In terms of signal processing, intrinsic safety barrier manufacturers have abandoned the traditional method of converting analog signals into frequency signals and then transmitting the signals through photoelectric coupling, and adopted modulation and demodulation technology. This technology significantly improves the product's precision, temperature drift, and anti-interference ability.

Precautions for the correct use of intrinsically safe barriers

1. To ensure the normal operation of the system, it is necessary to determine the parameters of the intrinsic safety barrier according to the parameters of the system. Parameters such as working voltage, maximum working voltage, and terminal resistance are important parts for the intrinsically safe barrier, and for isolating the intrinsically safe barrier, the achievable accuracy is more important.

Whether for Zener intrinsic safety barriers or isolation intrinsic safety barriers, there are also working environments, such as operating temperature and humidity, to be considered. In addition, whether the installation method is convenient for on-site installation, etc.;

2. It is necessary to determine the explosion-proof level that needs to be achieved according to the area that needs to be explosion-proof, whether it is Zone 0, Zone 1 or Zone 2. Finally, it can be determined whether to use the IA-level or IB-level intrinsic safety barrier;

3. The installation location must have a very reliable grounding system, and the grounding resistance of the intrinsically safe barrier must be less than 1Ω. Otherwise, the explosion-proof safety protection performance will be lost. Obviously, such requirements are very harsh and difficult to guarantee in practical engineering applications;

4. Field instruments from hazardous areas must be isolated, otherwise, the signal cannot be transmitted correctly after the ground terminal of the intrinsic safety barrier is connected to the ground. Because the signal is grounded, the anti-interference ability of the signal will be reduced directly, affecting the system stability;

5. The intrinsic safety barrier has a great influence on the power supply, and it is also easy to cause damage to the intrinsic safety barrier due to the fluctuation of the power supply;

6. Since the circuit principle of the intrinsic safety barrier needs to absorb the energy of the input loop, it is easy to cause the output to be unstable.

The above are six precautions that need to be paid attention to about the correct use of intrinsically safe barriers. The main principle of the most widely used zener-type intrinsic safety barrier today is to use a fast fuse, a current limiting resistor or a voltage limiting diode in the circuit to limit the input electrical energy, thereby ensuring the energy output to the dangerous area.