User manual

Rockwell Automation Publication 1769-UM011I-EN-P - February 2013 107
Develop Applications Chapter 7
• PROGRAM
• ROUTINE
• SERIALPORT
• TASK
• WALLCLOCKTIME
Monitor Connections
If communication with a device in the I/O configuration of the controller does
not occur for 100 ms or 4 times the RPI, whichever is less, the communication
times out, and the controller produces these warnings:
• The I/O status indicator on the front of the controller flashes green.
• A displays over the I/O configuration folder and the device (s) that
has timed out.
• A module fault code is produced, which you can access via:
– the Module Properties dialog box for the module.
– a GSV instruction.
Determine if Device Communication Has Timed Out
If communication times out with at least one device (module) in the I/O
configuration of the controller, the I/O status indicator on the front of the
controller flashes green.
• The GSV instruction gets the status of the I/O status indicator and stores
it in the I_O_LED tag.
• If I_O_LED equals 2, the controller has lost communication with at least
one device.
where:
I_O_LED is a DINT tag that stores the status of the I/O status indicator
on the front of the controller.
Get System Value
CIP Object Class MODULE
CIP Object Name
Attribute Name LedStatus
Dest I_O_LED
GSV
Equal
Source A I_O_LED
Source B 2
EQU