Broadcast and Receiver Operators
- Gary Cane
The Design Pad PROFIBUS generic hardware operators for broadcasting and receiving are programmed to exchange information with all or portions I/O Modules on slave devices. Their exact functionality changes depending on location of execution:
Broadcast Operator:
- In a Slave: A Design Pad Broadcast operator in a schema on a slave device writes data to an Input Module in its own memory for eventual transmission over the network when requested by its master.
- In a Master: A Design Pad Broadcast operator in a schema on a master device sends data over the network to an Output module in the target slave's memory.
Receiver Operator:
- In a Slave: A Design Pad Receiver operator in a schema on a slave device reads data from an Output Module in its own memory which can be written to by its master.
- In a Master: A Design Pad Receiver operator in a schema on a master device reads data over the network from an Input Module in the target slave's memory.
Figure 9.28 shows an example on how Fairmount Automation products exchange PROFIBUS information using Broadcast and Receivers in the slaves through Input Modules and/or Output Modules to/from Receivers and Broadcasters in the master.
Because multiple operations may read or write to or from different portions of an I/O Module, Figure 9.28 shows how Slave 1 has a program with operators Broadcast2a and b, each writing pieces of a message into the slave's memory for reading by the Master device. Conversely, operator Reveiver2 in Slave n's program takes data sent from the Master into the slave's memory into the program.
Figure 9.28 Interaction of I/O Modules and Broadcasters/Receivers
