Comparison between DCS and PLC
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How do the reliability of DCS and PLC compare now? If DCS can be redundant, its reliability is much higher than that of PLCs. Are there any other explanations?
If necessary, redundancy can also be required for PLCs. Power supplies, CPUs, communication modules/cards, and even important control circuits, etc., are all possible. So it seems that reliability can’t be generalized. I’ve seen manufacturers introduce PLCs with 3 CPUs, each responsible for tasks such as computation and communication; these CPUs have independent functions and do not interfere with one another. Moreover, their scanning cycle and program reading speed exceed those of mainstream DCS systems. Doesn’t that sound very reliable?
Today, mainstream brand PLC products all have high reliability. In terms of the products themselves, DCS and PLCs have similar reliability; what makes a difference is the system design, hardware configuration, and the development of application software, all of which can lead to variations in reliability. Even for the same model of DCS, different system designs and hardware configurations can result in differences in reliability.
I quite agree with the last sentence of 3L. Like it!~~
Looking at previous PLCs and DCS systems, PLCs were better suited to more harsh operating conditions; however, it seems that there isn’t much difference between modern DCS and PLCs these days
Now, DCS and PLC are becoming increasingly integrated, and this is also mentioned in the latest standard ANSI/ISA-5.1-2009. It is believed that as development progresses, these two systems will become more and more integrated until they merge into one, hehe~
There are many theories, but not many have been investigated nowadays.
Just as with the convergence of the three networks today, DCS and PLC are showing a trend of convergence. But I think the most important point is: a good DCS supports online downloading, while with PLCs the program runs from scratch after downloading