Understanding distributed control systems

For many industrial processes, individual processes can vary greatly across a geographical location. For example, consider a bottled water bottling center. Let’s assume the treatment process involves the following steps:

1. Run a pump to collect water from the local lake.
2. Open the water intake valve and intake the water into a heating tank to boil the water.
3. Take the boiled water and add minerals to the treated water.
4. Bottle the water.

For a process like this, which has four intermittent steps, multiple PLCs would need to be used. However, there is a catch to this process. The four steps are going to take place over the bottling plant, which by definition is geographically dispersed. Since the bottling process can be thought of as a single process, we’re going to need a way to control the whole process. Enter the world of DCSs.

A DCS is very similar to a SCADA system. A DCS is essentially a coordinating...