ELAP MEM440-Bus, Инструкция по эксплуатации

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MEM-BUS
EtherNet/IP™ ENCODER
Instruction Manual
ENIP_Manual_ENG 17/07/2018
6
The Producer/Consumer model has two significant benefits:

You do not need to configure routing table in the bridging modules, which greatly simplifies
maintenance and module replacement.

You maintain full control over the route taken by each message, which enables you to select
alternative paths for the same end device.
1.3 The “Producer / Consumer” Model
The CIP Producer/Consumer networking model replaces the old source/destination model (Known as
master/slave ). The Producer/Consumer model reduces network traffic and increases speed of transmission.
In traditional I/O systems, controllers poll input modules to obtain their input status. In the CIP system
input modules are not polled any more. Instead, they produce their data either upon a change of state or
periodically. The frequency of update depends upon the options that are chosen during configuration and
the topology of the network. Each input module, therefore, is a
producer of input data, while the controller
is a consumer of data.
The controller can also produce data for other controllers to consume. The produced and consumed data is
accessible by multiple controllers and other devices over the EtherNet/IP network. This data exchange
conforms to the Producer/Consumer model.
1.4 RPI Parameter
The requested packet interval (RPI) is the update rate that is specified for a particular piece of data in the
network. This value specifies how often to produce the data for that device. For example, if RPI = 50 ms, it
means that every 50 ms the device sends its data to the controller or the controller sends its data to the
device.
RPIs are only used for devices that exchange data. For example, a ControlLogix® EtherNet/IP bridge in the
same chassis as the controller does not require an RPI because it is not a data-producing member of the
system; it is used only as a bridge to remote modules.
1.5 EtherNet/IP™ topologies
ELAP MEM-BUS encoders can be connected in any of three network topologies: star, linear, or Device Level
Ring (DLR).
The linear topology uses the embedded switching capability to form a daisy chain style network that has a
beginning and an end.
Linear topology simplifies installation and reduces wiring and installation costs, but a break in the network
disconnects all devices downstream from the break.