What are the requirements and parameters that a professional programmer should analyze in common, whether for automation of machines or plants?

I MYSELF use the basic instructions of hardware failure, healthy rarely applied.

All valid contributions and good arguments are welcome.

Macgyver BR

 

I, myself, like to follow closely IEC61508:
1) Concept
2) Overall scope definition
3) Hazard and risk analysis
4) Overall safety requirments
5) Safety requirements allocation
--> 6) Overall operation and maintenance planning
--> 7) Overall safety validation planning
--> 8) Overall installation and commissioning planning
...
11) External risk reduction facitilities
...
13) Overall safety validation

Unfortunately, too often, risk reduction measures are not taken into consideration.

With the above definitions, I start writing the program part, where all shut-down levels are definied. This makes the programming for the activation of a device easier, since the possible shut-downs have already been defined up-front.

Safety critical functions are often monitored by a redundant controller, redundant sensors as per the safety requirements and the functions are monitored as:
- comparison demand and result (Output - input comparison or speed-ref. - speed feedback comparison).
- And as an overall safety windows (max speed allowed, max. temperature allowed, etc.)

In my opinion, such a structered appraoch produces safer AND more reliable control systems.

I would gladly discuss this in more details to anybody (please contact me under [email protected], just remove the NO SPAM!)

Stephan