What are PLCs and DCSs?
Programmable logic controllers, or PLCs, are basic units of industrial automation processes. A PLC runs a user-designed program that operates a number of discrete input/output (I/O) arrangements within a limited amount of time. They run conveyors, electric motors, pneumatic presses, and many more tasks. PLCs must be able to stand up to the harsh conditions of an industrial setting, and they must be reliable. Overall, you must be able to trust the program running your PLCs.
A distributed control system, or DCS, is comparable to a PLC, but on a larger scale. Where PLCs usually control an individual process, a DCS controls and coordinates hundreds or thousands of different processes. Commands are relayed to lower-level processors all the way down to the plant level, where the individual processes are carried out.
While PLCs and DCSs are hardy, reliable, and easily monitored, PLC/DCS programming must only be done by experienced technicians. Even early ladder-logic programs are complex, and modern programs using more up-to-date language, such as BASIC, must be carefully constructed.
What to Use and When
PLC/DCS programming can be tricky when you’re considering the number of input/outputs needed to run your operation. Technology has advanced to make PLCs able to handle more I/O arrangements, and therefore control more processes. Some PLCs now function almost like a miniature DCS. This provides some programming difficulties, and overall, questions about functionality. When is it better to have a DCS to oversee a few PLCs, and when should you have many PLCs handling separate tasks in place of a DCS?
Innovative Automation Concepts is well-qualified to program your PLC or DCS, and can help you figure out which system is best for you to use. Here’s a short list of factors to consider in PLC/DCS programming, from Automation World.
- Response time. PLCs generally have a much quicker response time than DCSs, given their size and capability, so they should be used for processes that have time as a factor, such as building safety tasks (sprinkler systems or fire prevention measures).
- Scale. PLCs operate on a smaller scale than a DCS. If your facility is large and/or must handle a large number of tasks, a DCS is optimal.
- Redundancy. Trying to force a number of redundant tasks into a PLC program will drive up your operating costs rather than using a DCS.
- Complexity. Like redundancy, a DCS handles complex and continuous tasks more easily than a PLC. (However, some operations, such as pulp and paper manufacturing, are trending toward PLCs.)
- Process changes. A PLC is better equipped to handle a task that will not require much tweaking, so if your operation requires frequent changes in processes, a DCS is a better option.
- Vendor support.
Innovative Automation Concepts is your best option when you require PLC/DCS programming. Our experience with different systems and programming languages is second to none. We can work with systems running processes on a small or large scale, and improve any current programs to benefit you. We account for any potential restrictions, equipment needs, and costs when planning our projects, and keep you informed every step of the way. Plus, our availability is a key component of what makes us a prime option in PLC/DCS programming.