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Rockwell Automation Publication 1769-UM021G-EN-P - October 2015
Chapter 9
Use I/O Modules with CompactLogix 5370 L3 Controllers
Common Configuration Parameters
While the configuration options vary from module to module, there are some
common options you typically configure when using Compact I/O modules in a
CompactLogix 5370 L3 control system, as described in
Table 31
.
I/O Connections
A Logix5000™ system uses connections to transmit I/O data, as described in
Table 31 - Common Configuration Parameters
Configuration Option
Description
Requested packet interval (RPI)
The RPI specifies the interval at which data is transmitted or received over a connection. For 1769 Compact Local I/O modules, data is
transmitted to the controller at the RPI.
When scanned on the local bus or over an EtherNet/IP network, input modules are scanned at the RPI specified in the module
configuration. Typically, you configure an RPI in milliseconds (ms). For I/O modules, the range is 0.5…750 ms.
When scanned over a DeviceNet network, distributed input modules are scanned at the rate that the DeviceNet adapter that connects
the input modules to the network supports. For example, the scan rate for distributed 1734 POINT I/O™ over DeviceNet can only occur as
quickly as the 1734-ADN DeviceNet adapter can transmit the data.
Module definition
Set of configuration parameters that affect data transmission between the controller and the I/O module. The parameters include the
following:
•
Series - Hardware series of the module.
•
Revision - Major and minor firmware revision levels that are used on the module.
•
Electronic Keying - See
for Electronic Keying information.
•
Connection - Type of connection between the controller writing the configuration and the I/O module, such as Output.
•
Data format - Type of data that is transferred between the controller and I/O module and what tags are generated when the
configuration is complete.
Module Fault on Controller If Connection
Fails While in Run Mode
This option determines how the controller is affected if the connection to an I/O module fails in Run mode. You can configure the project
so that a connection failure causes a major fault on the controller or not.
The default setting is for the option to be enabled, that is, if the connection to an I/O module fails in Run mode, a major fault occurs on
the controller.
Table 32 - I/O Module Connections
Connection
Description
Direct
A direct connection is a real-time, data-transfer link between the controller and an I/O module. The controller maintains and monitors
the connection. Any break in the connection, such as a module fault, causes the controller to set fault status bits in the data area that is
associated with the module.
Typically, analog I/O modules, diagnostic I/O modules, and specialty modules require direct connections.
Rack-optimized
For digital I/O modules, you can select rack-optimized communication.
This option is used with distributed I/O modules and the Rack Optimization connection selection is made when configuring the remote
adapter. For example, if you want to use a rack-optimized connection with digital I/O modules in a remote 1734 POINT I/O system, you
configure the 1734-AENT(R) module to use a connection type of Rack Optimization.
A rack-optimized connection consolidates connection usage between the controller and the digital I/O modules in a remote chassis or on
one DIN rail. Rather than having individual, direct connections for each I/O module, there is one connection for the entire rack (or DIN
rail).
