Figure R 13: Circuit with standby redundancy
Denotes the presence of more resources than are required to perform the intended tasks. The redundancy is used in several technical areas to increase reliability and robustness or to achieve functional reliability or data security in the case of faults.
Technical redundancy:
Measures to increase the reliability of a system by providing two or more of the devices or sub-systems which are particularly vulnerable in parallel. The intended reliability requires more redundant elements as the individual element becomes less reliable. (Figure R 12).
As electrical (electronic) components are generally more vulnerable than fluid parts, the redundancy measures in fluid technology are focused on signal distribution. However, fluid systems may also have a redundant design. In doing so, the redundant devices (circuits) are connected such that they automatically assume the function of a failed device.
The presence of the same information in multiple instances constitutes redundancy in data processing. This enables the reconstruction of a defective or garbled message.
A distinction is made between:
Active redundancy (hot standby redundancy):
All redundant devices (circuits) collaborate constantly. This minimises the effect of errors on the working element. However, they are also subject to the same load and constant wear.
Passive redundancy (hot standby redundancy):
In each case, only one device (circuit) is in operation, while the other(s) is/are activated by a coupling element where necessary, i.e. in the case of a failure (Figure R 13).
Figure R 12: Increased reliability through parallel circuits of n redundancies in the case of three different confidence levels