ABB Symphony Harmony Series, Instruction, Page: 138 / 402

I/O Block
WBPEEUI240751C0 3 - 9
its operating voltages. Each 24 VDC input is fused and moni-
tored. Figure
3-8 details the block power section.
Logic Power
Redundant 24 VDC block logic power (BLP) is bussed through
the mounting column to the I/O module. The redundant BLP
power is auctioneered through summing diodes into a single
24 VDC. Onboard DC-to-DC converters d5 VDC,
+15 VDC, and –15 VDC operating voltages from the integrated
24 VDC.
The I/O module tests itself for a +5 VDC out-of-range condi-
tion. When this voltage is outside its normal operating range, a
hardware fault (i.e., power on reset) will occur and the block
operation will halt.
Power Monitor
The power monitor circuits test and report the status of the
redundant 24 VDC BLP inputs. The inputs are only tested for
Figure 3-7. Block Diagram - I/O Module
M E M O RY
I/O CH A N N E L
IN T ER FA C E
M AC H INE
FAU LT T IM E R
C P U
SP EC IA L
O PE R AT ION S
SW IT CH (S W 2)
H N E T
INT E R FAC E
LE D
D R IV ER S
I/O
CH A NN E L 1
I/O
C H A N N EL N
S TATU S
LE D S
SE RIA L LIN K
INT E R FAC E
I/O S EC T IO N
I/O
C
H
A
N
N
E
L
B
U
S
DA
TA
B
U
S
BL O C K
PO W E R
+ 5 V D C
A
B
B
B
A
A
+ 1 5 V D C -1 5 V D C
RE DU N DA N C Y
LINK
O R
STAT IO N LIN K
IF P
LF P
+24 V D C BL P
HN E T
F IEL D PO W ER
SE LE C T
T 00 5 59 A