More than just start and stop
Radim Kalousek
Project leader and software development engineer at Brütsch Elektronik AG
Machine program must be able to do more than just start and stop the machine. Proper functionality, product quality, a useful user interface and the safety of people, the environment and equipment must be guaranteed.
Program must handle exceptional situations, deal with them and inform the operator accordingly. It must guide the operator to resolve the problem when an intervention is required. If something special happens, the program must not get lost in nirvana. The program must expect the unexpected! This can be, for example, an interruption in communication, a partial or complete power failure, an interruption of a function before its completion, a malfunction of sensors and actuators, another sequence of upcoming events, an operator failure, etc.
The straight forward way is only a small fraction of what the program must manage. Each IF statement has at least one ELSE with it. Interlocks of machine parts and machines must be implemented. Alerting and instructing the operator to resolve the alarm situation must be implemented. Self-remedy functions must be implemented. Operator errors and their dangerous consequences must be avoided or limited. ...
What can the consequences be if a situation unexpected in the program occurs in reality? Do you have any experience?
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