How should isolation safety barriers be used safely?
发布时间：
2022-05-30
How should an isolation safety barrier be used safely? An isolation safety barrier transmits voltage and current signals from the hazardous area to the safe area by means of isolation and signal conversion, while outputting unidirectional or independent bidirectional current/voltage signals to the safe area. It can also establish a serial communication network in the safe area via its configurable communication interface. As an intelligent safety barrier, it allows users to configure the input signal type and output range using a dedicated programmer or a computer.
How should isolation safety barriers be used safely?
The isolation safety barrier isolates and converts voltage and current signals from the hazardous area before transmitting them to the safe area, where it outputs unidirectional or independent bidirectional current/voltage signals. It also supports serial communication networking in the safe area via a configurable communication interface. As an intelligent safety barrier, it allows users to configure the input signal type and output range using a dedicated programmer or a computer.
In terms of reliability, the isolation safety barrier employs three isolation techniques: input isolation, output isolation, and power supply isolation. All signal terminals are protected by voltage-limiting, current-limiting, and surge-suppression circuits. The combination of electromagnetic isolation and optoelectronic isolation ensures physical separation between intrinsically safe and non-intrinsically safe terminals, thereby enhancing product reliability. In signal processing, the safety barrier used in Mingtai’s testing terminals has abandoned the conventional approach of converting analog signals into frequency signals and then transmitting them via optocouplers; instead, it adopts modulation–demodulation technology, which significantly improves the product’s accuracy, temperature drift performance, and anti-interference capability. The following are several key points to observe when properly using a safety barrier:
1. To ensure the proper operation of the system, the parameters of the safety barrier must be determined based on the system specifications. The key parameters for a standard safety barrier include the operating voltage, maximum operating voltage, and termination resistance, whereas for an isolated safety barrier, the primary consideration is the achievable accuracy. In addition, whether it is a standard or isolated safety barrier, the operating environment must be taken into account, including factors such as ambient temperature and humidity, as well as the ease of on-site installation.
2. The explosion-proof rating must be determined based on whether the hazardous area is Zone 0, Zone 1, or Zone 2. Subsequently, it can be decided whether to use an ia or ib safety barrier.
3. The installation location must be equipped with a highly reliable grounding system, and the grounding resistance of the safety barrier must be less than 1 Ω; otherwise, its explosion-proof safety protection performance will be compromised. Clearly, this requirement is extremely stringent and difficult to meet in practical engineering applications.
4. Field instruments originating from hazardous areas must be isolated; otherwise, if the signal is grounded through the grounding terminal of the safety barrier, it will not be transmitted correctly. Signal grounding directly reduces the signal’s immunity to interference and compromises system stability.
5. Isolation safety barriers have a significant impact on power supply and are also prone to damage due to power supply fluctuations;
6. Due to the circuit principle of the safety barrier, which requires absorption of energy from the input circuit, output instability is prone to occur.
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