Rockwell Automation Publication 1606-RM111A-EN-P - July 2020
5
Terminology and
Abbreviations
Terms
Descriptions
DC 24V
A value that is displayed with the AC or DC before the value represents a nominal
voltage with standard tolerances (usually ±15%) included. For example: DC 12V
describes a 12V battery disregarding whether it is full (13.7V) or flat (10V).
24V DC
A value with the unit (V DC) at the end is a momentary value without any additional
tolerances included.
nom
Indicates a nominal value.
typ
Indicates a typical value.
— (alone in table cell)
A single dash alone in a table cell indicates that there is no information to be included
in that cell.
1+1 Redundancy
Use of two identical power supplies in parallel to provide continued operation following
most failures in a single power supply. The two power supply outputs should be
isolated from each other by using diodes or other switching arrangements. For
example, two 10 A power supplies are needed to achieve a 10 A redundant system.
N+1 Redundancy
Use of three or more identical power supplies in parallel, which are allowed to be
connected in parallel for higher output currents, to provide continued operation
following most failures in a single power supply. All power supply outputs should be
isolated from each other by using diodes or other switching arrangements. For
example, to achieve a 40 A redundant system, five 10 A power supplies are needed in
an N+1 redundant system. Ensure that the power supplies are allowed to be connected
in parallel to increase the output power.
Figure 1 - 1+1 Redundancy
Figure 2 - N+1 Redundancy
AC
DC
AC
DC
Load
+
-
IN 1
OUT
IN 2
AC
DC
AC
DC
AC
DC
AC
DC
AC
DC
AC
DC
IN 1
OUT
IN 2
IN 1
OUT
IN 2
IN 1
OUT
IN 2
Load
+
-