Rockwell Automation Publication 1769-UM021G-EN-P - October 2015
279
Develop Applications
Chapter 10
Monitoring I/O Connections
If communication with a device in the I/O configuration of the controller does
not occur in an application-specific period, the communication times out and the
controller produces warnings.
The minimum timeout period that, once expired without communication, causes
a timeout is 100 ms. The timeout period can be greater, depending on the RPI of
the application. For example, if your application uses the default RPI = 20 ms, the
timeout period is 160 ms.
For more information on how to determine the time for your application, see
Rockwell Automation Knowledgebase Tech Note 38535. The document is
available at
http://www.rockwellautomation.com/knowledgebase/
When a timeout does occur, the controller produces these warnings:
•
An I/O fault status code is indicated on the status display of the
CompactLogix 5370 controller.
•
The I/O status indicator on the front of the CompactLogix 5370
controller flashes green.
•
A
shows over the I/O configuration folder and over the devices that
have timed out.
•
A module fault code is produced, which you can access via the following:
–
The Module Properties dialog box
–
A GSV instruction
For more information about I/O faults, see the Major, Minor, and I/O Faults
Programming Manual, publication
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