
DESCRIPTION AND OPERATION
FAN ASSEMBLY
2 - 4
I-E96-508C
®
when any bus voltage (5 VDC,
±
15 VDC, or 24 VDC) falls out of
tolerance.
The bus monitor module also generates a power fail interrupt
signal if it receives a PFI from the DC transfer module, status
input one, or if the five VDC bus voltage is low (if selected). It
distributes this signal to process control modules in the
INFI 90 system cabinet.
FAN ASSEMBLY
The IEFAN03 and IEFAN05 Fan Assemblies contain six fans
that mount in one chassis. Its purpose is to keep the power
supplies and modules cool. The fans draw cooling air up
through the module mounting assemblies and force it through
exhaust vents (when present) in the top of the cabinet door.
MODULE MOUNTING UNIT
The IEMMU01 and IEMMU02 Module Mounting Units provide
mounting for the power modules and process control modules.
Two five-conductor flat cables link the power fail interrupt and
power module status signals, 5 VDC,
±
15 VDC, and 24 VDC,
MCOM and I/O COM from the system power bus bar to the
MMU card cage. A three-wire cable from the power input bus
bar to the MMU backplane supplies the power modules with
DC input power.
Cables are required to connect the communication buses
between multiple MMU card cages. The module bus uses a
three-wire, twisted cable, while the I/O expander bus uses a
flat, 40 conductor ribbon cable.
POWER MOUNTING UNIT
The power mounting unit (IEPMU01 and IEPMU02) mounts
and segregates power modules from INFI 90 process modules.
Each PMU is open on the top and bottom for air flow. There are
12 pairs of guides for mounting power modules, two side plates
and the backplane. The backplane uses bus bars rather than
traces for heavier currents.
POWER MODULES
The DC system power modules receive input power at the MMU
or PMU backplane. The IEPDS01 DC System Power Module
requires 24 VDC input power. The IEPDS02 DC System Power
Module requires 48 VDC input power. DC-to-DC converters
convert the primary input voltage to secondary regulated volt-
ages of 5 VDC,
±
15 VDC and 24 VDC. These voltages are avail-
able at the system bus bar for distribution to process control
modules. See Figures