Instructions

Basic Operation 16
Doc: HMSI-27-306, Rev. 3.11Anybus Communicator PROFIBUS User Manual
2.3.3 Master Mode
In this mode, the communication is based on a query-response scheme; when the gateway issues a query
on the subnetwork, the addressed node is expected to issue a response to that query. Nodes are not per-
mitted to issue responses spontaneously, i.e. without first receiving a query.
There is one exception to this rule; the broadcaster. Most protocols offer some way of broadcasting mes-
sages to all nodes on the network, without expecting them to respond to the broadcasted message. This
is also reflected in the gateway, which features a dedicated broadcaster node.
In Master Mode, Anybus Configuration Manager comes preloaded with most commonly used Modbus
RTU commands, which can conveniently be reached by right-clicking on a node in the Anybus Config-
uration Manager and selecting “Insert New Command”. Note however that this does not in any way
prevent other protocols based on the same query-response message-scheme to be implemented.
2.3.4 Generic Data Mode
In this mode, there is no master-slave relationship between the nodes on the subnetwork and the gate-
way. Any node, including the gateway, may spontaneously produce or consume a message. Nodes do
not have to respond to messages, nor do they have to wait for a query in order to send one.
In the figure above, the gateway “consumes” data that is “produced” by a node on the subnetwork. This
“consumed” data can then be accessed from the higher level network. This also works the other way
around; the data received from the higher level network is used to “produce” a message on the subnet-
work to be “consumed” by a node.
Subnetwork Devices
Gateway
Control System
Subnetwork Devices
Control System
Gateway