This chart illustrates basic concepts in error-proof system design. The illustration is of a manually controlled boiler, namely in which the operator needs to control the temperature manually.
The operator can turn the machine on or off using an activation control (a power on-off switch). The operation is based on the operator's perception of the machine performance.
This design is error-prone. The critical component is this design is the operator, who might not notice risky situations, such as mal functioning.
Such design implies that the operator needs to monitor the machine state continuously. This design demonstrates the need for informing the operators about the machine state.
Updated on 18 Jan 2017.