Analyzing the work of programmers


Thread Starter

Macgyver BR

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

Stephan Markwalder

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!)