4 Fault Isolation
4.13 Power System Indicators
384 HPM High-Performance Process Manager Service R688
Honeywell December 2020
Alarms
The primary Power Supply Module alarm and secondary Power Supply Module alarm contacts monitor
five functions within each Power Supply Module. They will open if:
The dc output voltage is not within normal limits.
AC input power to the supply has failed.
The Power Supply Module electronics have overheated or the Power Supply Module fan has failed.
The 48 V backup battery system has failed because the batteries have discharged or they have been
disconnected.
The battery charger in the Power Supply Module has failed.
Three annunciator contacts are shown in the following figure. These contacts are normally wired in series
by the user as illustrated.
Figure 187 Standard Power System Annunciator Contact Connections
CMOS alarm
The CMOS Backup Alarm contacts open if the CMOS backup batteries have been removed or the
batteries have been degraded to where the CMOS charging and monitoring circuit has determined they
should be replaced.
Component replacement
Power System component replacement is discussed in the “Removal and Replacement” section.