User Manual
Table Of Contents
- Logix5000 Controllers I/O and Tag Data
- Summary of changes
- Table of contents
- Preface
- Communicate with I/O modules
- Organize tags
- Force I/O
- Data access control
- Introduction
- External access
- Configure external access
- External access availability
- User-defined type considerations
- Add-on instructions external access considerations
- Tag mapping considerations
- Imported tag behavior
- Constant value tags
- Configure constant tags
- Constant check box availability
- Add-on instructions constant value considerations
- Index
Communicate with I/O modules Chapter 1
formats. Each format uses a different data structure. The communication format
that you choose also determines:
• Direct or rack-optimized connection on page 13.
• Ownership on page 14.
Direct or rack-optimized connection
The Logix5000 controller uses connections to transmit I/O data. These
connections can be direct connections or rack-optimized connections.
Term Definition
Direct connection 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 with the I/O module. Any break in the connection, such as a module fault or
the removal of a module while under power, sets fault bits in the data area associated with the module.
A direct connection is any connection that does not use the Rack Optimization Comm Format.
Rack-optimized connection For digital I/O modules, you can select rack-optimized communication. A rack-optimized connection consolidates
connection usage between the controller and all the digital I/O modules in the chassis (or DIN rail). Rather than having
individual, direct connections for each I/O module, there is one connection for the entire chassis (or DIN rail).
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