ABB Symphony Harmony Series - Page 161

4 - 6 WBPEEUI240751C0
Analog Output
Analog output channel failures detectable by the primary I/O
module that cause a failover to the backup I/O module
include:
• Failed output driver.
• Failed output amplifier.
• Failed output sample and hold circuit.
• Failed readback circuit.
- Amplifier failure.
Figure 4-3. AIN-120 Block - Current Mode (RFP Powered)
T03240A
+
+
+
+
+
+24 V
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
–
–
–
–
–
AMP
AMP
A/D
A/D
A
A
A
B
B
B
HNET
CPU
AND
HNET
IN T ER FAC E
CPU
AND
HNET
IN T ER FAC E
+24 V
4-20 mA
LOOP
250 τ