Allen-Bradley 1756-L72

170 Rockwell Automation Publication 1756-UM001M-EN-P - February 2012
Chapter 10 Develop Applications
Figure 36 - GSV Used to Identify I/O Timeout
For more information about attributes available with the Module object, see the
Logix5000 Controllers General Instructions Reference Manual, publication
1756-RM003
.
Determine if I/O Communication to a Specific I/O Module has Timed
Out
If communication times out with a device (module) in the I/O configuration of
the controller, the controller produces a fault code and fault information for the
module. You can use GSV instructions to get fault code and information via the
FaultCode and FaultInfo attributes of the Module object.
For more information about attributes available with the Module object, see the
Logix5000 Controllers General Instructions Reference Manual, publication
1756-RM003
.
Interrupt the Execution of Logic and Execute the Fault Handler
Depending on your application, you might want an I/O connection error to
cause the Controller Fault Handler to execute. To do so, set the module property
that causes a major fault to result from an I/O connection error. The major fault
then causes the execution of the Controller Fault Handler.
First, develop a routine in the Controller Fault Handler that can respond to I/O
connection faults. Then, in the Module Properties dialog box of the I/O module
or parent communication module, check Major Fault On Controller If
Connection Fails While in Run Mode.