Trusted High Integrity Power Supply System
3. Configuration
Rockwell Automation Publication PD_T8200
Issue 11
13
3.
Configuration
3.1.
Current Sharing
The Modules are capable of current sharing by connecting their outputs together in parallel.
This can be done external to the Chassis or by using a shorting bar that mounts directly to
the output terminals on the Chassis backplane. This allows separate groups of Modules from
within a single Chassis to have their outputs configured as Single, Dual or N+1. The Module
uses a passive ‘droop’ method of current sharing and will share to within 25 % of the rated
load.
3.2.
REGENT
Power Supply Load Units
When using the Power Supply System with Regent and Plus , power supply loading
is based on the number of I/O Modules in the I/O Chassis and the load imposed by each I/O
Module. Load units for each I/O Module are shown in that Module’s product description
and specification sheet under the
Safetybus Power
heading. A set of three Power Supply
Modules will provide the following load units:
Number of I/O Units (Chassis):
1
2
3
4
Load Unit Capacity:
82
78
74
70
Table 6 Available Load Units (for a set of three power supplies)
Calculating the number of load units in the system helps determine the number of I/O
Power Supplies required by the system. For economic power distribution, and to avoid
overloading individual Power Supply Units, calculate power supply loading when configuring
systems.
3.3.
Regent I/O Triplicated Power Distribution
A Chassis can contain two sets of triple-redundant Power supplies for Regent I/O. Each of
the triple-redundant I/O Power Supply Modules within the I/O Power Supply Chassis
provides power for one leg of the three redundant legs of the I/O Safetybus Transceivers,
and provides power to all the I/O Modules within its associated I/O Chassis. Each I/O
Module contains a diode OR power-sharing circuit that receives power from all three I/O
Power Supply Modules.
Should any I/O Power Supply Module fail, only one leg of the transceiver modules loses
power: the two remaining legs maintain proper Regent operation. In addition, all the I/O
Modules continue to operate properly by drawing their current from the two remaining
Power Supplies within the I/O Power supply assembly.
