ABB Symphony Harmony Series, Instruction, Page: 139 / 402

3 - 10 WBPEEUI240751C0
I/O Block
their presence or absence. The circuits do not test the inputs
for voltage range.
The power monitor circuits also test and report status for the
internal field power (IFP) or external local field power (LFP)
input depending on the field power select jumper setting.
Again, the circuits only test for the presence or absence of the
field power input.
The I/O block will generate an SOA alarm if the fuse for any of
these inputs is bad or if the input voltage is absent.
Refer to the
Block Power and Mounting Hardware Block Power and Mounting Hardware Block Power and Mounting Hardware Block Power and Mounting Hardware
instruction
for a complete explanation of BLP, IFP, and LFP power, and the
SOA alarm signal for power status monitoring.
Central Processing Unit
The central processing unit (CPU) contains a microprocessor
and its supporting circuitry. The CPU interprets and executes
instructions to control the I/O block functions. Its responsibil-
ities include executing the I/O block portion of the control con-
figuration and controlling:
•
Hnet communication.
•
Analog and digital I/O processing.
•
Redundancy or station link communication.
•
Block diagnostics.
Figure 3-8. Block Power
P OW E R
AU C TIO N E E R
P OW E R
FILTE R
P OW E R
M O N ITO R
F IE LD P O W E R
S E LE C T
5 V D C
P O W E R
R E G U LATO R
15 V D C
P O W E R
R E G U LATO R
+ 24 V D C +24 V D C
S O A
A LA R M
P O W E R
S TAT U S
F IE LD
P O W E R
B LO C K
P O W E R
+15 V D C
+5 V D C
– 15 V D C
IF P /LFP
B LP B
B LP A
IFP
LFP
+24 V D C
FR O M
M O U N TIN G
C O LU M N
T 0056 0B