Tips to Choosing Between Centralized & Distributed Control System
When it comes to working with numerous developers on a single project and collaborating with them, many of us are aware of version control. There is no question that version control facilitates and accelerates developer work.
Now, the question is, which one is the best or which one must be chosen? We’ll compare their workflows, learning curves, security, popularity, and other features.
Most organizations employ either a Centralized Version Control System (CVCS) such as Subversion (SVN) or a Concurrent Version System (CVS) or a Chint Distributed Control System such as Git (Written in C), Mercurial (Written in Python), or Bazaar (Written in Python).
Distributed Control System
Let’s start by looking at the possibilities available in a distributed design.
The quantity and quality of CPUs utilized in distributed control systems are dictated by the number of modules. Each module has its own controller, and the system often includes a central master PLC that handles functions like logistics, parts tracking, and statistics. Module PLCs automate their particular sections and often lack visualization and operation capabilities.
The Benefits of Distributed Systems
- It is simple to add and delete nodes from a distributed system without compromising overall system performance.
- In distributed systems, there is no single point of failure. Even if a node fails or is removed from the system, the system can still function. As a result, high fault tolerance.
- Because each node has sufficient computing capability, the task may be distributed among numerous computers. This decreases the likelihood of a single computer becoming overloaded.
The Drawbacks of Distributed Systems
- More effort must be made to safeguard the network, and users must manage duplicate data across many sites.
- Because there is no common clock for the whole system, designing and debugging algorithms for the system is more complex.
- Because there is no central server, messages and information may be lost in the network system.
Centralized Control System
In contrast to dispersed architectures, central architectures often include a computer, commonly a PC, that handles all duties such as I/O connections, PLC, and motion control. As a result, computing capability must be greatly increased. However, since there is only one CPU, only one such spare component is required.
Software: In order to be reusable and maintainable, software must be organized and modularized. For this aim, IEC 61131 specifies object-oriented techniques. Because there is just one PLC program, storing and archiving are easy, as is central start-up or shutdown of the PLC.
The Benefits of Centralized Systems
- Client nodes may be readily added and withdrawn without disrupting the entire system.
- Because of the client-server design, it is simple to set up and develop.
- The central server can administer and monitor the whole system. As a result, there is a Single Point of Control.
The Drawbacks of Centralized Systems
- Because the whole system’s availability is dependent on the central server, system upgrades must be performed on the fly. This makes server maintenance harder.
- Longer access times for clients located distant from the server, as well as inefficient scheduling methods, may result in hunger.
- Backups are less likely to be kept. If the central server fails and no backup is available, all data would be lost.
The architecture of distributed local control technologies is quite organized. Individual module replacement and testing are simple. Standard fieldbuses may be utilized without issue because of the basic topology. However, communication between modules, with the master computer, and for synchronizing the PLCs during start-up and shutdown is somewhat difficult.
The key reasons for employing central control technology are central diagnostics, commissioning, and maintenance, as well as easy plant start-up and shutdown, as well as simple administration of a single PLC program. A PC can control and synchronize a large number of axes if the fieldbus is strong enough.
You may use any of them, however, DVCS provides greater benefits if you just follow the flow of its instructions. All of the above facts show that DVCS has more benefits and is more popular than CVCS, but when it comes to picking a version control, it also relies on which one is easier for you to understand as a beginning.