ABB S800 Product Manual page 154

Power Supply and Cooling Requirements
Calculation of 24V d.c. Power Consumption
Total 24 V d.c. current consumption = V load ModuleBus +  V load
ModuleBus*0.3 +  V external load.
The calculated 5 V ModuleBus load should not exceed 1.5 A.
If many of the modules has a power consumption >125 mA at 5 V, the maximum
load could be exceeded. See
The calculated 24 V ModuleBus load should not exceed 1.4 A.
If many of the modules has a power consumption >125 mA at 24 V, the
maximum load could be exceeded.
To ensure bumpless performance of the I/O system including DO880, the power
supply for the I/O field power should be able to support at least short circuit on
one DO880 channel in addition to the total nominal load. For Short circuit current
for DO880, see Technical Data in S800 I/O Modules and Termination Units.
The following rules must be considered if ABB power supply units are being
used together with DO880.
- When using SS823, the base load must not exceed 16 A.
- With a redundant power supply configuration, consisting of two SD823 + one
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SS823 in parallel with two SD823 + one SS823, the base load must not exceed
16 A.
Section 3 Technical Data and Performance
Table 32 for data.
3BSE015969-600 A