Table of Contents
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Chapter 1
About ArmorBlock Modules
Use of the Common
Industrial Protocol (CIP)
Understand the Producer/
Consumer Model
Specify the Requested
Packet Interval (RPI)
10
For a complete ControlLogix® compatibility matrix, see the Integrated
Architecture® and CIP Sync™ Configuration Application Technique,
publication IA-AT003.
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.
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.
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 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 module 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.
Rockwell Automation Publication 1732E-UM003D-EN-E - November 2021
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