Identifying the Duty Cycle
The following procedure should be followed when identifying duty cycles:
1. Determine the operational duty cycle for the system.
2. From consideration of the system duty cycle and the functions of the sub-systems, determine the duty cycle for each sub-system.
3. For each sub-system, determine the operational duty cycle of each item comprising the particular sub-system. Highlight any item whose duty cycle differs from that of its parent sub-system, and define the duty cycle for that particular item.
Generally, it is convenient to show the duty cycles in the form of a diagram like that shown in Figure 4-1.
1. Determine Reliability expressions for Areas A, B and C, i.e.:
2. Determine Reliability expressions for Areas D and E, i.e.:
3. Combine Reliability expressions for Areas A, D and E to give System Reliability, i.e.:
