Jetter JC-120MC, Руководство пользователя

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JC-120MC Programming
Publish/subscribe
Publish/subscribe is used as communication architecture for cyclic data
interchange in the Jetter Ethernet system bus. The JetSym Hardware
Manager generates the configurations for cyclic data interchange and
transfers them to the controller. Based on this configuration, the configuration
automatically carries out cyclic data interchange.
Basic data interchange via publish/subscribe is executed by the publishers
and subscribers in the operating system of the Jetter devices at the Jetter
Ethernet system bus.
Publisher

The publishers publish data of the network node, on which they are being
processed.
 A data record is published by the publisher. Therefore it is called
publication .
 A publisher can manage several publications.
Subscriber
 The subscribers which are interested in these data receive the publications
and transfer the contents to the data of the network node on which they are
processed.

A data record is received by the subscriber. Therefore it is called
subscription .
 A subscriber can manage several subscriptions.

To receive a publication, there must exist a corresponding subscription.
 One publication can be received by subscriptions on various network
nodes simultaneously, as the publications are published via multicast
frames.
JetSym
When a combination of a controller and one or several network nodes is
configured in JetSym, the Hardware Manager generates the configuration files
for the publishers and for the subscribers. The Hardware Manager generates
one-to-one relationships between the publications and the subscriptions.
If, in Hardware Manager, you add network nodes with the modules connected
to them, Hardware Manager will automatically generate the process data
belonging to these modules as publish/subscribe variables.
Features of publish/subscribe
Parameter Value Description
Number of network nodes 000 ... 199 200 network nodes max.:
They are entered into the Hardware
Manager by their name and as GNN
Maximum amount of
process variables per
publication/subscription
64 64 process variables max:
This corresponds to 256 bytes of
process data
Introduction
Basic data interchange
Features of
publish/subscribe