ABB Symphony Harmony Series, Instruction, Page: 163 / 402

4 - 8 WBPEEUI240751C0
Digital Input
across an input of one I/O module due to an I/O block fault
will result in a false, unchanging zero state input. An open in
an input channel circuit of the base will not allow either I/O
module to read the input.
An input state change error for a digital input will cause a fail-
over to the backup I/O module. This error occurs when one of
the digital inputs is changing state faster than the module can
handle. It is typically caused by a problem with the input
source. All digital channel LEDs will flash steadily and at the
same rate to indicate this type of error.
Figure 4-5. AIN-220 Block - Current Mode (IFP or LFP Powered)
T 0 32 4 1 A
R E F 1
R E F 1
R E F 16
R E F 16
1
1
16
16
C H 1
C H 1
C H 16
C H 16
•
•
•
•
•
•
•
•
•
•
•
•
A IN -22 0 M O D U LE
A IN -22 0 M O D U LE
R E D U N DA N C Y LIN K
R E D U N DA N C Y LIN K
A M P
A M P
A M P
A M P
A /D
A /D
A /D
A /D
O P TO -
C O U P LE R
O P TO -
C O U P LE R
O P TO -
C O U P LE R
O P TO -
C O U P LE R
A
A
A
B
B
B
H N E T
C P U
A N D
H N E T
IN T E R FAC E
C P U
A N D
H N E T
IN T E R FAC E
+
+
+
+
R E D U N DA N T
A IN -220 B A S E
–
–
–
–
+
+2 4 V
15 0
τ
250 τ
IF P /L FP
–
IF C /LF C
4-2 0 m A
LO O P