Problems with plans for flammable and toxic systems

I’ve encountered it; on-site, it’s the controller provided by the manufacturer of the complete set of instruments. On the DCS side, only the communication measurement point data types from the equipment manufacturer are required, along with the register addresses. It can be added in the DCS communication card configuration; the configuration can be packaged and then unpacked. If followed strictly in accordance with industry standards, this is non-compliant. Everyone in the chemical industry knows the importance of GDS. Because communication can be disrupted by environmental factors.

Flammable gas and toxic gas detectors are devices used to monitor the concentration of specific gases in an environment; they issue alarms or take other safety measures when the gas concentration reaches dangerous levels. These detectors can be connected to a central control system for monitoring, data recording, alarm functions, and remote control. The communication method refers to the data transmission method between the detector and the controller. The common communication methods between detectors and controllers include the following: 1. Wired communication: including analog signals (such as 4-20 mA current loops) and digital communication (such as RS-485, Ethernet, etc.). In wired communication, terminal junction boxes can be used to centrally manage the wiring of multiple detectors, facilitating maintenance and cabling. 2. Wireless communication: such as ZigBee, Wi-Fi, Bluetooth, LoRa, etc. Wireless communication methods can reduce wiring work, making it easier to install detectors in locations where wiring is difficult or mobility is required. In wireless communication, a terminal junction box may not be necessary, as the signals are transmitted directly to the controller via wirelessly. Whether a terminal junction box is needed usually depends on the following factors: – Engineering design: If the detectors are located close to each other and in a concentrated area, a junction box is typically used to manage the power and signal wires centrally, thereby facilitating wiring and maintenance. - Communication method: When using wired transmission, to reduce the number and length of cables between the control room and various detection points, junction boxes are often installed near those detection points. Wireless transmission may not be necessary. - On-site environment: In locations susceptible to environmental influences such as high temperatures, dust, humidity, etc., using junction boxes can provide better protection for cable connections and distribution points. - Maintenance and safety requirements: The junction box facilitates the maintenance and inspection of the system, while ensuring the safety of cable connections. In practical applications, regardless of the communication method used, the decision to employ a terminal junction box must be based on various factors such as the specific application environment, security requirements, ease of maintenance, and costs. Typically, detailed design plans should be planned and implemented by professional security system engineers or system integrators based on actual requirements. .

The biggest weakness of communication methods is their susceptibility to interference; in case of communication failures, it is difficult to identify the issue. If conditions permit, it is recommended to use 4–20mA wired connections, as they are stable and reliable. I once encountered a situation where 485 communication failed at dozens of locations in a petrochemical storage area; it took half a month to diagnose the problem. . . .