ABB Symphony Harmony Series - Page 160

Analog Output
WBPEEUI240751C0 4 - 5
module so that only one I/O module is driving the outputs at a
time (Fig. 4-8). A short across an output of one I/O module
due to an I/O block fault will not affect the output of the other
I/O module. An open in the output channel circuit of the base
will not allow either I/O module to control the output.
NOTE: Normal failover time for the AOT-150 block is less than 100 millisec-
onds. Under rare conditions, the output channels could be affected by a failover
for up to 200 milliseconds.
Figure 4-2. AIN-120 Block - Current Mode (IFP or LFP Powered)
T03232A
+
+
+
+
+
+24 V
150
τ
250 τ
IF P /L F P
REF1
REF1
REF2
REF2
CH 1
CH 1
•
•
•
•
•
•
CH 16
CH 16
MUX
MUX
REDUNDANT
AIN-120 BASE AIN-120 MODULE
AIN-120 MODULE
REDUNDANCY LINK
REDUNDANCY LINK
–
–
–
–
–
IF C/L F C
AMP
AMP
A/D
A/D
A
A
A
B
B
B
HNET
CPU
AND
HNET
IN TE RFAC E
CPU
AND
HNET
IN TE RFAC E
4-20 mA
LOOP