GE GFK-0825F Display and Clear Faults from a PLC

GFK-0825F Chapter 6 Diagnostics and Fault Clearing 6-5

Display and Clear Faults from a PLC

A PLC places faults from a Field Control station in the I/O and PLC Fault Tables.

The content of t he I/O fault d i splay depend s on the revision l evel of the PLC' s Bus Control l er

module, and the type of programmer software being used. With a Bus Controller that is version

4.6 or later, when a fault occurs on a Field Control station, the I/O Fault Table shows the station ID

and the rack and slot within th e station where the fault has occu r r ed:

14#0.4

Serial Bus Address

Rack

Slot

If the Bus Controller is only a rev. 3 version, it cannot transfer to the PLC the detailed fault

information provided by a Bus Interface Unit. Instead, a rev. 3 Bus Controller reports any fault

from a remote station as a GENA fault. To clear the fault ta ble, press the Clear (F9) key.

You must clea r the I/O Fault Ta ble from the pr ogr amming softwa re for the faul t to be

cleared in the PLC CPU and for the associated fault contact to be cleared. Clearing faults

with a Hand-held Monitor alone does not remove them from the Fault Table, or cause any

associated -[FAULT]- contacts to stop passing power flow.

Clearing the I/O Fault Ta bl e at the PLC causes the Bus Contr oller to send a Clear All

Circuit Fa ul ts backgroun d m essage to all bl ocks on the bus. Faults can be cle a red from the

Fault Table either from the fault table display or by the application program.

Clearing the fault tabl e removes the faults it contain s; it does not clear fault con ditions in

the system. If the conditi on that caused a fault still exi sts and is detected, the fault will be

reported again.

Note: If faults are cleared from the P LC befor e the BIU has received output s fr om the

PLC, some faults such as Loss of Module or Extra Module are lost.

The PLC Fault Table shows the station ID and the location in the station where the fault occurred:

14#0.4

Serial Bus Address

Rack

Slot

Pressing the Clear key from th i s display clears the entir e PLC Fault Table. If there ar e no faults in

the I/O Fault Table, th en pr essing Clear will also clear Bus I n t erface Unit faults.

If the host CPU is a Series Five or Series Six PLC, faults from a Field Control station are displayed

in the Genius Fault Table. Faults from Field Control stations are identified as GENA faults. The

GENA is the component with in the Bus Interface Unit that han dles the Genius bus interfa ce.

Pressing the Clear Faults key clears all faults currently in the fault table. This sets the fault count to

zero, and sends a Clear comman d to the Bus Interface Unit .