Using Fault Contacts; Using Point Faults; Using Alarm Contacts - GE PACSystems RXi User Manual

Fault Address
#SFT_CPU %SB0013
(fatal)
#STOR_ER %SB0014
(fatal)

14.3.2 Using Fault Contacts

Fault (-[F]-) and no-fault (-[NF]-) contacts can be used to detect the presence of I/O faults in
the system. These contacts cannot be overridden. The following table shows the state of fault
and no-fault contacts.
An NF contact will be ON (F contact will be OFF) when the referenced I/O point is not faulted,
or the referenced I/O point does not exist in the hardware configuration.

14.3.3 Using Point Faults

Point faults pertain to external I/O faults, although they are also set due to the failure of
associated higher-level internal hardware (for example, IOC failure or loss of a rack). To use
point faults, they must be enabled in Hardware Configuration on the Memory parameters tab
of the CPU.
When enabled, a bit for each discrete I/O point and a byte for each analog I/O channel are
allocated in CPU memory. The CPU memory used for point faults is included in the total
reference table memory size. The FAULT and NOFLT contacts (described in Using Fault
Contacts above) provide access to the point faults.
The full support of point fault contacts depends on the capability of the I/O module. Some
modules do not support point fault contacts. The point fault contacts for these modules
remain all off, unless a Loss of I/O Module occurs, in which case the CPU turns on all point
fault contacts associated with the lost module.

14.3.4 Using Alarm Contacts

High (-
input module comparator function. To use alarm contacts, point faults must first be enabled in
Hardware Configuration on the Memory parameters tab of the CPU.
The following example logic uses both high and low alarm contacts.
Note:
GFK-2816F
Description
CPU software fault. A non-recoverable error
has been detected in the CPU. May be caused
by Watchdog Timer expiring.
Download of data to CPU from the
programmer failed; some data in CPU may be
corrupted.
Condition
Fault Present
Fault Absent
[ [
HA]-) and low (- LA]-) alarm contacts are used to represent the state of the analog
HA and LA contacts do not create an entry in a fault table.
CPU immediately transitions to Stop-Halt
mode. The only activity permitted is
communication with the programmer. To
be cleared, controller power must be
cycled. Sets SY_FLT, SY_PRES, and
SFT_FLT.
CPU will not transition to Run mode. This
fault is not cleared at power-up,
intervention is required to correct it. Sets
SY_FLT and SY_PRES.
[F]
ON
OFF
August 2015
Chapter 14. Diagnostics
Result
[NF]
OFF
ON
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