LB900,S2000 series Zener safety barrierDetailed product description：

I. Overview
The LB900 and S2000 series Zener safety barriers are manufactured and produced in accordance with the relevant provisions of GB3836 · 4-2000 [Explosion proof Electrical Equipment for Explosive Gas Environments - Intrinsic Safety Type "i"]. Passed the explosion-proof testing by the National Instrument Explosion proof Quality Supervision and Inspection Center and obtained the explosion-proof qualification certificate.
The LB900 series Zener safety barrier can be combined with various on-site primary instruments such as transmitters (intelligent transmitters for digital communication, ordinary transmitters for 4-20mA analog signals, domestic DDZ-III transmitters), electrical converters, electrical valve positioners, various thermocouples, thermal resistors, switches (contacts and analog switches), flow instruments (flow transmitters for turbines, waist wheels, scrapers, eddies, etc.), solenoid valves, and various special instruments to form an intrinsic safety explosion-proof system. It is used for automation process control in modern industry and is widely used in fields such as petroleum, chemical, pharmaceutical, and shipbuilding. Reliable equipment that limits the entry of hazardous energy into explosive gas environments.
The use of the S2000 series Zener safety barrier has been expanded compared to the LB900 series safety barrier.

2、 Requirements for matching safety barriers with primary instruments
1. The selected safety barriers and primary instruments should obtain explosion-proof qualification certificates issued by the national explosion-proof inspection department, and can form an intrinsic safety explosion-proof system after confirmation by the explosion-proof inspection unit.
2. Both cables and primary instruments are energy storage devices and must be calculated according to the explosion-proof parameters of the safety barrier. Only after verification can they be used. (This condition does not take into account power source energy)
The basic combination conditions for intrinsically safe explosion-proof systems are:
Uo≤Ui
l0≤li
Co≥Ci+Cp
LO≥Li+Lp
Among them: Uo maximum output voltage
Io maximum output current
Co maximum load capacitance
Lo maximum load inductance
The maximum allowable input voltage for a single instrument in Ui
The maximum input current allowed for a single instrument
Ci maximum internal equivalent capacitance of a single instrument
Li's maximum internal equivalent inductance for a single instrument
Maximum allowable distributed capacitance for Cp connecting wires (or cables)
Maximum allowable distributed inductance for Lp connecting wires (or cables)
3. According to national standards, the intrinsic safety energy level limit is:
Level IIC: 20J
IIB level: 60J
When the intrinsic safety limit energy level of an instrument and a safety barrier is different, the explosion-proof system formed by them can only be downgraded for use.

3、 Structure and working principle
1. Structure
The LB900 and S2000 series Zener safety barriers adopt a unified appearance and installation size. The safety barrier circuit is encapsulated with flame-retardant epoxy resin inside the shell. The creepage distance, electrical clearance, and relative leakage index of the material between each terminal comply with the relevant provisions of GB3836.4 and GB3836.1.

2. Working principle
i、 Basic circuit of Zener safety barrier: see Figure 3-1
ii ii、 The circuit consists of a fast fuse FAl, a voltage limiting element VD1
The component consists of three parts.
VD2 (Zener diode or diode), current limiting resistor (resistor or non-linear)
Under normal operating conditions, if the voltage applied between non local terminals 1 and 2 is lower than the maximum voltage Vmax (even lower than the Zener voltage of the Zener diode), VDl and VD2 are in a non-conductive state. Except for a very small leakage current, they are in an "open circuit" state. The safety barrier circuit is equivalent to a resistor connected in series in the signal circuit. As long as the leakage current is less than the specified value, the safety barrier circuit will not affect the normal operation of the system.
When a fault occurs in the non local safety end, such as when high voltage is mixed between non local safety ends 1 and 2 for some reason, causing the Zener diodes VD1 and VD2 to reverse breakdown and enter a "conducting" state, the Zener diodes VD1 and VD2 limit the mixed high voltage to the Zener voltage, and no high voltage will appear on the local safety ends 3 and 4 of the safety barrier. Once the Zener diode conducts, its current rises sharply (the avalanche process instantly melts the fuse FAl connected in series in the circuit, cutting off the high voltage to the site, preventing the danger of high voltage detonating explosive substances on site, thus protecting the safety of on-site equipment and personnel.
When a fault occurs on site (within the danger zone), such as a load short circuit, the current limiting resistor in the safety barrier circuit immediately acts to limit the short-circuit current within a certain current value, which is a safe value, so the site is also safe.
The safety protection function of a Zener safety barrier is actually a limiting effect on energy, which is a limiting effect on energy in intrinsic safety explosion-proof systems. In the intrinsic safety explosion-proof system, due to the function of the safety barrier, the energy transmitted to the site (danger zone) is guaranteed to be a safe value (will not ignite the prescribed graded and grouped explosive gas mixture) regardless of any malfunction, thereby ensuring site safety.

4、 Technical specifications and main parameters
a) Explosion proof mark: [Jux (ia)] IIC [Ex (ib)] IIC
b) Installation location: Safe area
c) Installation method: D, N standard guide rail (35mm) installation or guide bar busbar installation
d) Maximum allowable voltage: 250VAC/DC
e) Environmental conditions: Continuous use temperature -10+45 ℃