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Use of the common industrial protocol (cip), Understand the producer/ consumer model, Specify the requested packet interval (rpi) – Rockwell Automation 1732E-OB8M8SR EtherNet/IP Dual Port 8-Point SOE Input and Scheduled Output Modules UM User Manual

Page 12: Understand the producer/consumer model

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Rockwell Automation Publication 1732E-UM003B-EN-E - March 2014

Chapter 1 About ArmorBlock Modules

For a complete ControlLogix compatibility matrix, see publication

IA-AT003

.

Use of the Common
Industrial Protocol (CIP)

The 1732E-IB8M8SOER and 1732E-OB8M8SR modules use the Common
Industrial Protocol (CIP). CIP is the application layer protocol specified for
EtherNet/IP, the Ethernet Industrial Protocol. It is a message-based protocol that
implements a relative path to send a message from the “producing” device in a
system to the “consuming” devices.

The producing device contains the path information that steers the message along
the proper route to reach its consumers. Because the producing device holds this
information, other devices along the path simply pass this information; they do
not need to store it.

This has two significant benefits:

• You do not need to configure routing tables 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.

Understand the Producer/
Consumer Model

The CIP “producer/consumer” networking model replaces the old source/
destination (“master/slave”) model. 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 by a controller. Instead, they produce their data
either upon a change of state (CoS) or periodically. The frequency of update
depends upon the options chosen during configuration and where on the
network the input module resides. The input module, therefore, is a producer of
input data and the controller is a consumer of the 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.

Specify the Requested
Packet Interval (RPI)

The Requested Packet Interval (RPI) is the update rate specified for a particular
piece of data on the network. This value specifies how often to produce the data
for that device. For example, if you specify an RPI of 50 ms, it means that every

1756-EN2T, 1756-EN2TR, 1756-EN3TR

3.x version when using RSLogix 5000 v18 or later

RSLogix 5000 software

18 or later

RSLinx software

2.56 or later

Product

Firmware Version / Software Release