Generally speaking, there are two types of processes in manufacturing: discrete and analog. A discrete process is a manufacturing methodology that will produce separate widgets. In other words, a production line may output one item, two items, three items, etc. An analog production process is where the plant will create a quantity of product that is quantifiable by weight. Examples include the production of beverages, sauces, raw ingredients, etc. Although it is possible to design a flow that will continuously output the product, such production is often managed in batches. It is important to note that although batches are considered to be analog or continuous flow, most of them end up being packaged for consumption which converts them into a discrete manufacturing process.
This is a companion discussion topic for the original entry at https://www.solisplc.com/tutorials/plc-programming-example