Just like other chart types, EPC charts are constructed according to certain rules. Because organisations want to use this chart type in different ways, it is possible to adjust some of these rules.
By combining a number of rules, you create a set of limits that defines how the chart can be constructed. It is therefore important to think carefully about these rules. If a chart does not comply with these rules, you will receive error messages when saving the chart. This can be very frustrating if you have set-up your chart the way you want it only to discover that it cannot be saved. You will then have to discover which rule is causing the problem and disable it.
Below is a description of each rule:
An EPC chart must start and stop with an event: Each process chain must have a beginning situation to get the process started. It must also have an end situation to close the process.
Only logical connectors can split of join the process after an event or function: If a process is split you have to define whether all possible paths (AND), and/or (OR) or an (XOR)
Logical connectors must have more than one incoming or outgoing control flow arcs: A logical connector can only split or merge a process. It cannot be used unless the process is split into at least two branches. A logical connector can then either merge two or more paths and create even more branches.
Events and functions must alternate: An event always results in a function and a function always results in an event. It is not possible for an event to end up with another event without some interaction from a function. The same applies to functions. A function cannot lead to another function without interaction with events.
Only logical OR connections and logical XOR connectors can split the process after a function: An action does not necessarily lead to two events. It leads to either an AND/OR situation or one of the possible events.
Only logical AND connectors can split the process after an event: A specific event can lead to two or more actions but not to one or the other when the process is split.
Functions cannot join to an event: Multiple actions cannot lead to a single event.
