Basic Operation
2-5
Master Mode
In this mode, the communication is based on a Query/Response scheme; when the gateway issues a
Query on the sub-network, the addressed node is expected to issue a Response to that Query. Nodes
are not permitted 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
messages 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, ABC Config Tool comes pre-loaded with most commonly used Modbus RTU com-
mands, which can conveniently be reached by right-clicking on a node in the ABC Config Tool and se-
lecting ‘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.
Generic Data Mode
In this mode, there is no master-slave relationship between the nodes on the sub-network 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 sub-network. 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 sub-net-
work to be ‘Consumed’ by a node.