As described in Redundancy, redundancy exists when the number of units required for system operation is less than the total number of units in the system. For example, if the number of units required for system operation is 1 and the total number of units in the system is 2, a 1-out-of-2 parallel redundancy exists.

You can construct a combination of series and parallel redundancies in the same diagram. Redundancies can be represented in one of two ways. If all redundant components are identical, you can insert a single block in the diagram. On the Redundancy page in the block’s Calculation Properties window, you specify the total number of redundant components, the redundancy type, and the number of components required for system operation. For more information, see Redundancy Page.

If the redundant components are not identical, you can insert multiple blocks in the diagram to represent these components and then insert a junction that connects all of these blocks together. On the Redundancy page in the junction’s Calculation Properties for the junction, you specify the total number of redundant components, the redundancy type, and the number of components required for system operation. For more information, see Redundancy Page.

While you can use the standard Windows copy-and-paste technique to copy a block and paste it in different areas of a diagram, sometimes these multiple blocks represent the same physical unit. In such cases, the block should be accounted for in the calculations only once, regardless of the number of times it is repeated in the diagram. To accomplish this, you must designate that the copied block is a repeat of the original block. For more information, see Specifying a Block is a Repeat. During Monte Carlo simulation, if that unit is assumed to fail during random simulation, it fails in all related locations.