Rockwell Automation Publication ICSTT-RM448J-EN-P - April 2018
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Before You Begin
Chapter 4
• Make sure that the power distribution cabling is sized to allow the
maximum prospective fault currents and tolerable voltage losses. This is
specifically important where floating supplies are employed and other
power sources can cause high prospective fault currents if multiple earth
faults occur.
Controller Power Supply Requirements
A controller requires the following power supply sources:
• A dual redundant power supply of + 24 Vdc with an operating range of
18 Vdc to 32 Vdc. The AADvance controller is designed to accept
supply transient and interference according to IEC 61131 part 2.
An over current fault in the controller must not cause the system to lose power.
Consequently, the power sources must be able to supply the peak current to
open any over current protection devices (such as fuses) without failing.
The power supply protection of the controller is in the modules, the power
distribution arrangement must have a circuit breaker on the input side of each
power source. The controller is designed to be resistant to a reverse polarity
connection without permanent damage.
The power sources must come from a commercially available industrial un-
interruptible power supply (UPS) system. An applicable UPS must have the
capacity sufficient to satisfy the entire system load (including field devices and
the controller) and an applicable contingency allowance for projected future
expansion.
Power Arrangements for Field Devices
Output modules use an external source of power for field devices. This may be
the power source used for the controller or a separate power source.
• For digital and analogue outputs a field power supply of +24 Vdc within
a range of 18-32 Vdc is required.
Recommended field circuits are given for each type of I/O module later in the
section "Connecting Field Wiring".
WARNING:
The power supplies must satisfy the electrical requirements and
tests specified in IEC 61131 EN 61010-1 and EN 60950 and must be big
enough for the system requirements.
IMPORTANT
It is highly recommended that the negative side of the field supply be
connected to earth (ground). This will avoid possible fail danger conditions
that can be caused by some earth fault monitors used with floating power
supplies.
