【2026 Control Systems】Basis and Key Points for Identifying Hidden Dangers in DCS Systems
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1. The inspection is based on GB/T 50770-2013 \"Code for Design of Safety Instrumented Systems in Petrochemical Industries\": For the control room, the temperature should be 20±2°C and the humidity should be ≤60%RH. Regarding controller redundancy, the switching time should be ≤100ms and the output variation should be ≤±0.5%FS. IEC 61511-1:2016 \"Functional Safety – Safety Instrumented Systems\" stipulates that systems of SIL2 or higher level require a 1oo2D redundant architecture. ISA-18.2-2016 \"Alarm Management\"/EEMUA 191:2013 \"Guidelines for Alarm System Management\" require that the number of alarms per display screen be ≤10, with clear priorities. GB/T 2887-2011 \"General Specifications for Computer Rooms\" addresses requirements related to the electromagnetic environment and UPS power supply
2. Key inspection points: Redundant reliability: Verify whether the controller, power supply, and communication modules are truly redundant, and check whether the power supply comes from an independent circuit. Alarm management: Review the number of alarms, priority classification, and suppression logic to ensure that the rate of invalid alarms is ≤5%. Permissions and security: USB ports are disabled, and any changes to critical parameters require dual verification ； Also check the network isolation and firewall configurations.
3. Case: A factory experienced DCS downtime due to a single-controller architecture, which violated GB/T 50770-2013; it was ordered to upgrade to a dual-redundancy architecture. Another company suffered a system crash due to a virus in its engineer stations, as it lacked network protection; although its hardware met the requirements, it violated the provisions of GB/T 22239-2019 on cybersecurity level protection.
For reference: In the operation of hazardous chemicals and chemical processing units, automation systems such as DCS, PLC, SIS, and GDS serve as both the \"brain\" for production control and the \"last line of defense\" for safety protection. During hazard identification, it is necessary to refer to **standards (GB), international standards (IEC/ISA/API), and industry regulations**, as well as documents such as the \"Guidelines for Identifying and Addressing Safety Risks and Hazards in Hazardous Chemical Enterprises\", to ensure that the entire process of design, operation, and maintenance remains compliant and under control.
Specific requirements: The \"Guidelines for the Identification and Rectification of Safety Risks and Hazards in Hazardous Chemical Enterprises\" specify mandatory items such as DCS/SIS independence, GDS coverage rate, and PLC emergency stop functions.
“Regulations on Safety Management of Instrumentation Systems in Chemical Enterprises”: Modifications to interlock logic require the implementation of an MOC process, along with a HAZOP analysis.
\"Guidelines for the Implementation of Process Safety Risk Management in Chemical Enterprises\": The SIS system must undergo full-circuit testing annually.
MOC scope expansion: In addition to logical modifications, it also includes hardware replacement, firmware upgrades, and network structure adjustments.
1. Industrial control network security: In accordance with GB/T 30976-2014 Guidelines for Security Protection of Industrial Control Systems, identify issues such as weak passwords, remote access, and patch management.
2. Emergency plan integration: Check whether GDS/SIS alarms are integrated with emergency broadcasting and the dispatch center to ensure timely information transmission.