Rockwell Automation T82xx Trusted High Integrity Power Supply 110-240V ac and 24V dc - Manual (Page 15)

Trusted
TM
Power Supply System T82xx
Issue 9 Mar 06 PD-T82xx 15
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 Regent+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:
Available Load Units (for a set of three power supplies)
Number of I/O Units
(Chassis):
Load Unit Capacity:
1
82
2
78
3
74
4
70
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.
I/O transceivers and I/O modules require power fail and reset status signals for proper operation.