ABB AC 800M, Hardware And Operation

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Section 3 Configuration Powering Units in the Cabinet
3BSE 027 941 R301 103
Powering Units in the Cabinet
This power supply is only connected to units within the cabinet such as:
• PM8xx, which also powers all communication interfaces (via the CEX-bus)
and all S800 I/O units connected to its electrical ModuleBus.
• TB820V2/TB840 (optical modem for S800 I/O) which also powers all S800
I/O units connected to its electrical ModuleBus.
• CI830 (PROFIBUS DP interface for S800 I/O) which also powers all S800 I/O
units connected to its electrical ModuleBus.
• PROFIBUS DP and PROFIBUS DP-V1 adapters for other I/O systems
(depending on the supply arrangement for the I/O units, it may be necessary to
connect power to each I/O unit).
• Communication modems located in the cabinet.
The main configuration rule for this power supply is to retain the 24 V cables within
the cabinet.
Powering Field Equipment outside the Cabinet
This is intended for supplying power to process signals and equipment located
outside the cabinet.
Interference
Powering field equipment from a power supply located in the AC 800M Controller
cabinet often requires the use of long 24 V DC cables that can easily pick up local
interference and direct it straight back to the power supply units. When installing the
cables follow the Field Cables, given under
Cables on page 45.
Short circuit at the power supply output
The SD82x series power supply has no extra energy reservoir at its outputs. In the
event of a short circuit the power supply output voltage will fall rapidly.
Short circuits (even with fuses installed in the 24 V DC distribution system) or large
load changes can produce unwanted voltage dips in supply.