E_SR and E_RS unsymmetric behaviour ? #2452

I wouldn't call the behavior of E_SR or E_RS as "unsymmetric".

agrre

IEC 61499 Annex A defines that both FBs will only issue an output event when QO is changing. QO is initialized with FALSE so after these blocks are started an R event will not change QO and therefore no EOis issued.

which is logical and good for most Systems.

Your proposal would change that and then the question would be why the first time different then the other times.

in many Systems you need to Output the Intial State. So there can be a HMI Display, or other Actor connected to that E_SR or E_RS, that needs to be initialized with TRUE or FALSE wether the RS/SR got a R or S Event. Initialize it first FALSE and then TRUE when the S Event comes makes it flickering on the Output (say it is white initially and turns Red for false and Green for true) users do not want to see the red...

many other Samples can be found where it is required that the first Event may it be R or S comes immediately through. As said, this is not true for any Application.

But long story short symmetric would not be a name that would help me to know that I need your block.

I agree. We must find a better sounding name.

As we are now getting more and more event blocks that are not in IEC 61499 Annex A I think we need to start to think how we show our users that these are extensions to the predefined ones. Especially if users come from different IEC 61499 systems. Not yet shure if this should then be an own lib (e.g., event_ext) or if it should be a subdirectory inside of the event lib. Both have their pros and cons.

yes, agree.