• E_PERMIT
• E_CTU
To communicate between devices, an additional PUBLISH_X/SUBSCRIBE_X pair must be used. As
one can identify, these blocks are not seen when looking at a whole distributed system and should
be seen as an intermediary between devices.
The PUBLISH_X FB is used to send messages over the network which are received by an according
SUBSCRIBE_X FB. Every time a REQ is triggered, a message is sent according to the ID input. With
the value of the ID input you can specify what specific network protocol you would like to use (e.g.,
MQTT). If you don’t specify a dedicated protocol the default as defined in the ”IEC 61499 Compliance
Profile for Feasibility Demonstrations” is used. The number X in PUBLISH_X is the number of data
elements that you want to send in the message. Since we are only sending one value we used
PUBLISH_1.
The used ID value specifies an IP:PORT pair.
142
