Do people use the MTBF concept when evaluating the reliability of DCS?
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Process control station CPU: Pentium/400M/64MRAM; Electronic disk: DOC 32M; Capacity of algorithm blocks: 10,000; Capacity of real-time database: 10,000 points; Network configuration: two 100Mbps Ethernet connections; CAN interface: ISA bus; Operating temperature: 0~70°C. Intelligent input/output module: Analog signal accuracy: 0.1% for large signals, 0.3% for small signals; SOE resolution: 1ms; Operating temperature: 0~70°C. Human-machine interface: CPU: PIV/2.4G/512M DRAM; CRT/LCD resolution: 1600×1200; Image refresh time: less than 0.5S; Data refresh time: 0.5S. Reliability: Redundancy in process control stations (PU), power supplies, and networks; MTBF > 100,000 hours. What significance does this parameter have in practical applications?
This is the parameter that represents the system’s average fault-free operating time; the higher its value, the greater the reliability of the system.
For any DCS system that is well-known, its MTBF has no practical meaning in real-world applications! For now. These values are many times higher than the specified requirements. But indicators are still just indicators; it’s the actual results of their use that matter. Moreover, relatively speaking, whether the system design is reasonable and the skill level of the personnel responsible for debugging directly determine the stability of this project. Even though Honeywell’s TPS has an MTBF of up to 200,000 hours, will your device stay operational for 20 years without stopping? Even if the system itself can indeed meet this requirement, if your project is assigned to an incompetent project engineer, as a result, the system crashes frequently and requires constant troubleshooting. Even if the hardware is not damaged. What’s the use of a high MTBF value for hardware? Focus on some more practical indicators – something that is more \"practical\".
It is essential for bid evaluation; domestic systems can handle 100,000 hours, while foreign systems can handle 1 million hours
MTBF doesn’t have much practical significance; it is merely a statistical figure with only reference value and no real practical use. Perhaps even the DCS manufacturers don’t know how this figure is determined. Even when a failure occurs, it’s not possible to use this figure to obtain any compensation
During the bidding process, this can be used as an excuse to reject some bids that aren’t desired, hehe. In reality, no matter what kind of system it is, its construction and application in China are always guided by human factors. The quality of design, construction, and commissioning, as well as the level of maintenance required, along with the users’ skill levels, all influence the stability of the system. The key lies in the institutional constraints of the company; high standards are set for the system throughout its entire lifecycle, from design and construction to commissioning and operation, which ensures high stability for the system.
MTBF --- mean time between failures: the average time between successive failures; it is a value obtained through long-term statistics. Who is responsible for conducting these statistics? Who will monitor it? It has no practical value; word of mouth is better.