Pepperl + fuchs isolation grid and zener grid two differences

Pepperl+Fuchs safety barrier is the core product of Pepperl+Fuchs (PEPPERL+FUCHS). Its rich variety and ability to deal with special application problems have been in a leading position in the world. Its products are widely used in petroleum, chemical, petrochemical, natural gas, medicine and other industrial fields where flammable and explosive dangerous places exist. It has always been the most popular product in the field of industrial automation.

Pepperl+Fuchs safety barriers have two categories: isolation barriers and Zener barriers.

Pepperl+Fuchs isolation barriers mainly include K series, H series, E series, WE series, and CR series; Pepperl+Fuchs Zener barriers mainly include: Z series and SB series.

What is the difference between Pepperl+Fuchs safety barrier isolation type and Zener type? We can know by simple comparison.

Zener safety barrier

Fast fuses, current-limiting resistors or voltage-limiting diodes are used in the circuit to limit the input electrical energy so as to ensure the energy output to the hazardous area. Its principle is simple, the circuit is easy to realize, and the price is low. However, due to its own principle defects, its reliability in its application is greatly affected and its application range is limited. The reasons are as follows:

　　　 1. The installation location must have a very reliable grounding system, and the grounding resistance of the Zener safety 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 actual engineering applications.

2. It is required that the field instruments from the dangerous area must be isolated, otherwise the signal cannot be transmitted correctly after the ground terminal of the Zener safety barrier is connected to the earth, and the signal grounding directly reduces the signal anti-interference ability and affects the system stability .

3. The Zener safety barrier has a great impact on the power supply, and it is also easy to damage the Zener safety barrier due to power fluctuations.

　　　　 Isolated safety barrier

1. It adopts a circuit structure that electrically isolates the input, output, and power supply from each other, and meets the requirements of intrinsically safe limited energy. Compared with Zener security, although the price is more expensive, its outstanding performance advantages have brought greater benefits to user applications:

2. Because of the three-way isolation method, there is no need for system grounding, which brings great convenience to design and site construction.

3. The requirements for instruments in hazardous areas are greatly reduced, and there is no need to use isolated instruments on site.

4. Since the signal lines do not need to share the ground, the stability and anti-interference ability of the detection and control loop signals are greatly enhanced, thereby improving the reliability of the entire system.

5. Isolated safety barriers have stronger input signal processing capabilities, and can receive and process signals such as thermocouples, thermal resistances, and frequencies, which cannot be achieved by Zener safety barriers.

6. The isolated safety barrier can output two mutually isolated signals to provide to two devices using the same signal source, and ensure that the signals of the two devices do not interfere with each other, and at the same time improve the electrical safety insulation performance of the connected devices .

　　　 Therefore, comparing the characteristics and performance of the Pepperl+Fuchs safety barrier Zener and the isolation type, it can be seen that the Pepperl+Fuchs safety barrier isolation has outstanding advantages and more extensive uses, although its price is slightly higher than the Pepperl+Fuchs safety barrier Zener However, considering the design, construction, installation, commissioning and maintenance costs, the overall cost may be lower than the Pepperl+Fuchs safety barrier Zener. In engineering sites with high requirements, Pepperl+Fuchs isolated safety barriers are used as the main intrinsically safe explosion-proof instruments. Pepperl+Fuchs isolated safety barriers have gradually replaced the Zener type, and have become increasingly popular in the field of safety and explosion protection. application.