Alarms - GE PACSystems RX3i Genius User Manual

Chapter 4. System Operation

4.1.4 Alarms

Whenever an alarm condition occurs on a Genius Device, a background message (datagram)
is transmitted from the device to the GCG001. This transmission occurs while the alarmed
device has the Genius Bus token. Upon reception, the GCG001 formulates an Alarm message
to be passed to the PNC001, which in turn passes it to the RX3i CPU. The RX3i takes
appropriate action and notifies the operator per the logic in the application.
Alarms may be cleared programmatically using either the Clear Circuit Fault COMMREQ (see
Figure 25) or the Clear All Circuit Fault COMMREQ, or via the Genius Hand-Held Monitor (HHM).
Note that whenever the HHM is used to clear a circuit fault, the GCG001 will not be aware of
this condition, thus will not have cleared the corresponding fault. Under these conditions, the
"Diagnosis Disappears" Fault will not have been logged and any subsequent fault from the
same point will not be reported to the I/O Fault Table. Be sure to follow up any HHM clearing
of faults with a COMMREQ to clear the same fault(s) in order to eliminate the discrepancy
described here.
Typically, the field problem needs to be investigated and resolved before the alarm can be
successfully cleared. For the alarm to be cleared, the alarm condition must no longer be
present and the Genius device must receive a suitable background message instructing it to
clear the alarm notification. If the alarm condition is absent, the Genius device will cease to
exhibit the alarm indication (LEDs will operate normally again). If the alarm condition is still
present, a new alarm cycle will be initiated. See Sections 6.4.5, 6.4.6 and 6.4.4 for related
COMMREQ or Data_Init_Comm instructions. Refer to GEK-90486-1, Genius I/O System and
Communications User's Manual, for further details.
As mentioned in Section 1.8, the behavior of the input references associated with a Genius
Device that has indicated a fault, and which is interfaced to the CPU via the GCG001, is to
cause all inputs to either hold last state or to default to a known state (per GCG001
configuration parameters). If this behavior is problematic for your application, you can disable
fault reporting at the block, using the Genius Hand-Held Monitor (HHM) – see "Report Faults" in
GEK-90486-2. The downside is that your application will no longer be able to automatically
sense faults at the corresponding Genius Device. The LEDs on the Genius Device will continue
to indicate Fault conditions; however no datagram will be issued for each fault occurrence. An
intermediate solution is to periodically query each such device with a "Read Diagnostics"
datagram (Section 6.4.4) and parse the response in order to detect faulted circuits.
36 Public PACSystems RX3i Genius Communications Gateway User Manual GFK-2892B