This section will show you how to make applications communicate using the default FBDK/ip protocol as defined in the IEC 61499 Compliance Profile for Feasibility Demonstrations. Because we are going to use the default protocol, we don't have to put it as a parameter in the beginning of the ID input of the Communication Function Blocks. We only have to provide an IP address and port in the following format:
So an ID like:
will be automatically converted into this:
To communicate using Publish/Subscribe FBs, a UDP/IP connection is utilized, so we have to provide the Publish/Subscribe Function Blocks with a multicast IP address and a port. The Publish FBs will send data over the network in this multicast IP address/port and the Subscribe FBs will listen to the same multicast IP address/port receiving any data sent by the Publish FBs. Multicast IP addresses can be picked from the range 224.0.0.0 - 239.255.255.255, while the port is arbitrary. So an example ID parameter for the Publish/Subscribe FBs would be:
In contrast to Client/Server pairs (see next section), Publish/Subscribe FBs don't have to work in pairs. Any Subscribe FB in any device listening to this multicast IP address will receive data sent by any Publish FB in this multicast IP address.
An example of using a Publish/Subscribe FBs can be seen in the figure below and can be summarized as follows:
Note that
To communicate using a Client/Server pair, a TCP/IP connection is utilized, so we have to set a Server in one device listening to a certain port and have a Client in another device connect to this Server using the first device's IP address and Server's listening port. The Client FB will send a request to the Server FB using the Server FB's IP address and port and the Server FB will respond after processing the received data. So if the Server is running in a device with IP address 192.168.0.2 listening to port 61501, an example of the ID parameters used for the Client/Server pair would be:
Server
Client
However the "localhost" attribute is just for informational reasons and will not be used by FORTE, i.e. the Server's IP address will always be the same as the device's IP address. Only the port attribute is used. In contrast to Publish/Subscribe FBs, Client/Server FBs work in pairs. Only one Client FB can be connected to a Server FB at a time, while a Client FB can be connected to only one Server FB.
An example of using a Client/Server pair can be seen in the figure below and can be summarized as follows:
Note that
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