Re: [4diac-dev] Detecting self-cycles in ECC

[Martin Melik-Merkumians <Melik-Merkumians@xxxxxxxxxxxxxxxxx>]

Hi,

 

empty transitions are illegal as far as I know, so that would be an incomplete transition anyhow.

 

The loop check with a 1 transition is a good idea, as this would result in a deadlock situation, as the FB would never stop executing blocking all other FBs on the resource and possibly flooding the event chain.

 

Best regards,

Martin

 

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Dipl.-Ing. Martin Melik-Merkumians

Advanced Mechatronic Systems

Automation and Control Institute (ACIN)

TU Wien

DVR-Number: 0005886

 

Gusshausstr. 27-29, room CA-05-38

1040 Vienna, Austria

Phone: +43 (0)1 588 01 37688

Fax: +43 (0)1 588 01 937688

Email: melik-merkumians@xxxxxxxxxxxxxxxxx

http://www.acin.tuwien.ac.at/

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Von: 4diac-dev-bounces@xxxxxxxxxxx <4diac-dev-bounces@xxxxxxxxxxx> Im Auftrag von Sándor Bácsi
Gesendet: Donnerstag, 4. Juni 2020 09:25
An: 4diac developer discussions <4diac-dev@xxxxxxxxxxx>
Betreff: [4diac-dev] Detecting self-cycles in ECC

 

Hi,

As a first step, I started to implement OCL constraints to detect inconsistencies in ECC. Such an inconsistency can be, for example, if we create self-cycles in the ECC. A self-cycle exists when there is a transition from an EC state back to itself. If there is no event associated with such a transition, it can happen that the executor may enter an infinite loop. Therefore, I think we should warn users about self-cycles gated by "1" or "[None]". I created an OCL invariant which can detect self-cycles, which are gated by "1" or "[None]".

Gated by "[None]":

   Gated by "1":

 

Since I am a newbie to ECC, I would like to ask your opinion on this constraint. What do you think is this the right direction for detecting self-cycles? What previous experiences do you have with self-cycles in ECC? 

Cheers,
Sándor