Master Mode - Anybus Communicator Modbus plus 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.
Control System
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 pre-
vent other protocols based on the same query-response message-scheme to be implemented.
Anybus Communicator for Modbus Plus
Doc.Rev. 3.01
Gateway
Basic Operation 18
Subnetwork Devices
Doc.Id. SCM-1200-093