Rockwell Automation 1768-PA3, 1768-PB3 Installation Instructions
Installation Instructions
1768 CompactLogix Power Supplies
Catalog Numbers 1768-PA3, 1768-PB3
Topic Page
Important User Information 2
About the 1768 Power Supplies 5
Safety Circuits 11
Main Power Disconnect 12
Install the Power Supply 16
Mount the Power Supply 16
Place 1769 I/O Modules in a 1768 CompactLogix System 22
Interpret the LED Indicators 23
Specifications 27
Additional Resources 31
About This Publication
Use this publication to install the 1768-PA3 and 1768-PB3 CompactLogix power
supplies.
Publication 1768-IN001B-EN-P - July 2006
2 1768 CompactLogix Power Supplies
Important User Information
Solid state equipment has operational characteristics differing from those of electromechanical equipment.
Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (publication
SGI-1.1 available from your local Rockwell Automation sales office or online at
http://literature.rockwellautomation.com) describes some important differences between solid state
equipment and hard-wired electromechanical devices. Because of this difference, and also because of the
wide variety of uses for solid state equipment, all persons responsible for applying this equipment must
satisfy themselves that each intended application of this equipment is acceptable.
In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages
resulting from the use or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many
variables and requirements associated with any particular installation, Rockwell Automation, Inc. cannot
assume responsibility or liability for actual use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits,
equipment, or software described in this manual.
Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell
Automation, Inc., is prohibited.
Throughout this manual, when necessary, we use notes to make you aware of safety considerations.
WARNING
Identifies information about practices or circumstances that can cause an explosion in
a hazardous environment, which may lead to personal injury or death, property
damage, or economic loss.
IMPORTANT
ATTENTION
SHOCK HAZARD
BURN HAZARD
Identifies information that is critical for successful application and understanding of
the product.
Identifies information about practices or circumstances that can lead to personal injury
or death, property damage, or economic loss. Attentions help you to identify a hazard,
avoid a hazard, and recognize the consequences.
Labels may be located on or inside the equipment, for example, a drive or motor, to
alert people that dangerous voltage may be present.
Labels may be located on or inside the equipment, for example, a drive or motor, to
alert people that surfaces may be dangerous temperatures.
Publication 1768-IN001B-EN-P - July 2006
1768 CompactLogix Power Supplies 3
North American Hazardous Location Approval
The following Information applies when operating this
equipment in hazardous locations:
Products marked "CL I, DIV 2, GP A, B, C, D" are suitable for
use in Class I Division 2 Groups A, B, C, D, Hazardous
Locations and nonhazardous locations only. Each product is
supplied with markings on the rating nameplate indicating
the hazardous location temperature code. When combining
products within a system, the most adverse temperature code
(lowest "T" number) may be used to help determine the
overall temperature code of the system. Combinations of
equipment in your system are subject to investigation by the
local Authority Having Jurisdiction at the time of installation.
WARNING
EXPLOSION HAZARD
Do not disconnect equipment
unless power has been removed
or the area is known to be
nonhazardous.
Do not disconnect connections to
this equipment unless power has
been removed or the area is
known to be nonhazardous.
Secure any external connections
that mate to this equipment by
using screws, sliding latches,
threaded connectors, or other
means provided with this product.
Substitution of components may
impair suitability for Class I,
Division 2.
If this product contains batteries,
they must only be changed in an
area known to be nonhazardous.
Informations sur l'utilisation de cet équipement en
environnements dangereux:
Les produits marqués "CL I, DIV 2, GP A, B, C, D" ne
conviennent qu'à une utilisation en environnements de
Classe I Division 2 Groupes A, B, C, D dangereux et non
dangereux. Chaque produit est livré avec des marquages sur
sa plaque d'identification qui indiquent le code de
température pour les environnements dangereux. Lorsque
plusieurs produits sont combinés dans un système, le code
de température le plus défavorable (code de température le
plus faible) peut être utilisé pour déterminer le code de
température global du système. Les combinaisons
d'équipements dans le système sont sujettes à inspection
par les autorités locales qualifiées au moment de
l'installation.
AVERTISSEMENT
RISQUE D'EXPLOSION
Couper le courant ou s'assurer
que l'environnement est classé
non dangereux avant de
débrancher l'équipement.
Couper le courant ou s'assurer
que l'environnement est classé
non dangereux avant de
débrancher les connecteurs. Fixer
tous les connecteurs externes
reliés à cet équipement à l'aide
de vis, loquets coulissants,
connecteurs filetés ou autres
moyens fournis avec ce produit.
La substitution de composants
peut rendre cet équipement
inadapté à une utilisation en
environnement de Classe I,
Division 2.
S'assurer que l'environnement est
classé non dangereux avant de
changer les piles.
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4 1768 CompactLogix Power Supplies
Environment and Enclosure
ATTENTION
This equipment is intended for use in a Pollution Degree 2 industrial
environment, in overvoltage Category II applications (as defined in IEC
publication 60664-1), at altitudes up to 2000 meters (1.24 mi) without
derating.
This equipment is considered Group 1, Class A industrial equipment
according to IEC/CISPR Publication 11. Without appropriate precautions,
there may be potential difficulties ensuring electromagnetic compatibility
in other environments due to conducted as well as radiated disturbance.
This equipment is supplied as open-type equipment. It must be mounted
within an enclosure that is suitably designed for those specific
environmental conditions that will be present and appropriately designed
to prevent personal injury resulting from accessibility to live parts. The
enclosure must have suitable flame-retardant properties to prevent or
minimize the spread of flame, complying with a flame spread rating of
5VA, V2, V1, V0 (or equivalent) if non-metallic. The interior of the
enclosure must be accessible only by the use of a tool. Subsequent
sections of this publication may contain additional information regarding
specific enclosure type ratings that are required to comply with certain
product safety certifications.
Besides this publication, see:
Industrial Automation Wiring and Grounding Guidelines, Alllen-Bradley
publication 1770-4.1.
NEMA Standards publication 250 and IEC publication 60529, as
applicable, for explanations of the degrees of protection provided by
different types of enclosure.
Publication 1768-IN001B-EN-P - July 2006
Prevent Electrostatic Discharge
1768 CompactLogix Power Supplies 5
ATTENTION
This equipment is sensitive to electrostatic discharge, which can cause internal damage
and affect normal operation. Follow these guidelines when you handle this equipment:
• Touch a grounded object to discharge potential static.
• Wear an approved grounding wriststrap.
• Do not touch connectors or pins on component boards.
• Do not touch circuit components inside the equipment.
• Use a static-safe workstation, if available.
• Store the equipment in appropriate static-safe packaging when not in use.
About the 1768 Power Supplies
The CompactLogix power supply provides power through the CompactLogix
backplane. The backplane is built into the 1768 and 1769 power supplies,
controllers, and I/O modules.
In addition to backplane power, both the 1768-PA3 and 1768-PB3 power supplies
offer a 24V dc external power supply terminal.
1768-PA3 Power Supply
Input Power
Terminal
24V dc External
Power Terminal
1768-PB3 Power Supply
Input Power
Terminal
24V dc External
Power Terminal
Backplane Backplane
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6 1768 CompactLogix Power Supplies
1768-PA3 Power Supply
The 1768-PA3 power supply is a dual-input power supply that operates in multiple
ranges. The 1768-PA3 offers the following input power supply options:
• 85...265V ac
• 108...132V dc
1768-PB3 Power Supply
The 1768-PB3 power supply is a single-input power supply. The 1768-PB3 offers
the following input power supply range:
• 16.8...31.2V dc
About the Power Supplies in a CompactLogix System
The CompactLogix system is set up differently than other Logix systems. The
following are considerations specific to the CompactLogix system:
1768 CompactLogix System
Power supply provides 24V dc power to
controller through the backplane.
Power
Supply
Communication or
Motion Module
Communication or
Controller provides 5V dc
to communication and
motion modules.
Controller
Motion Module
Controller provides
5V/24V dc to 1769 I/O
modules.
1769 I/O Module
1769 I/O Module
• Both the 1768-PA3 and the 1768-PB3 power supplies require that a 1768
CompactLogix controller be installed in the same bank as the power supply
before the system is powered.
The power supply sends 24V dc to the controller located either immediately to the
right of the power supply or immediately to the right of the communication and
motion modules.
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1768 CompactLogix Power Supplies 7
The controller converts the 24V dc to 5V dc and distributes 5V dc and 24V dc
power as required by modules on the backplane. The following list describes
controller power distribution considerations:
• 5V/24V power goes to 1769 I/O modules on the right side of the controller.
• 5V power goes to 1768 communication or motion modules on the left side
of the controller.
• System power-up and power-down may take longer than expected.
• Full power-up should occur within a few seconds of turning on the power
supply. Power-down, however, takes significantly longer. When the power
supply is turned off, the CompactLogix controller uses some power to write
its program to internal memory. During this program write, there is activity
on the controller’s status indicators.
IMPORTANT
• If your system is not receiving power, the cause may or may not be the
power supply.
For example, if a 5V short exists in the 1769 I/O portion of the local chassis,
the controller faults and stops powering the 1769 I/O until the short
condition is corrected. In this case, the power supply is operating normally
and continuing to send 24V dc to the controller.
To troubleshoot any power supply issues, see Interpret the LED Indicators.
• 1769 CompactLogix I/O modules in the local chassis receive power from the
1768 power supply. However, banks of 1769 I/O modules remote to the
1768 power supply require that a 1769 power supply be installed in the
remote bank.
IMPORTANT
When you turn the CompactLogix power supply off, make sure you wait for all
status indicators on the power supply and controller to turn off before
disconnecting any part from the system.
If you disconnect the CompactLogix system while the controller is still writing
its program to memory, the program write will not be completed and you will
lose your program.
Never install a 1769 power supply on the local 1768 CompactLogix
backplane.
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8 1768 CompactLogix Power Supplies
• The 1768 power supply has a different distance rating than the 1769 power
supply. For more information, see Place 1769 I/O Modules in a 1768
CompactLogix System.
Use a Fuse with the Power Supply
The CompactLogix power supply has an internal, non-replaceable fuse soldered in
place. This fuse is intended to guard against fire hazard due to short circuit
conditions. We recommend you put a user-replaceable fuse in line between
incoming power and the power supply terminal block.
User Power Overcurrent Condition
In the event of an overcurrent condition, the power supply outputs latch off and
remain off until the overcurrent is removed and the power is cycled. Reload the
your program following a power supply shutdown.
ATTENTION
To avoid unexpected operation due to 24V dc user-power shutdown, monitor
the 24V dc user output with a 24V dc input channel.
Publication 1768-IN001B-EN-P - July 2006
1768 CompactLogix Power Supplies 9
1768-PA3 Power Dissipation and Requirements
The following tables show power dissipation and input power requirements of the
1768-PA3 power supply.
1768-PA3 Power Dissipation
35 W
30 W
Power
Dissipated
(Watts)
25 W
20 W
15 W
10 W
5 W
0 W
0 W 10 W 20 W 30 W 40 W 50W 60 W 70 W 80 W 90 W
1768-PA3 Input Power
Requirements
90 W
80 W
70 W
60 W
Total Output
Power
Backplane Plus
Auxiliary
(Watts)
50 W
40 W
30 W
20 W
10 W
0 W
6 W
0 W 20 W 40 W 60 W 80 W 100 W 120 W
12 W
6 W
Output Power (Watts)
18 W
Input Power (Watts)
90 W
30 W
90 W
118 W
Publication 1768-IN001B-EN-P - July 2006
10 1768 CompactLogix Power Supplies
1768-PB3 Power Dissipation and Requirements
The following tables show power dissipation and input power requirements of the
1768-PB3 power supply.
1768-PB3 Power Dissipation
35 W
30 W
25 W
Power
Dissipated
(Watts)
20 W
15 W
10 W
5 W
0 W
0 W 10 W 20 W 30 W 40 W 50W 60 W 70 W 80 W 90 W
1768-PB3 Input Power
Requirements
90 W
80 W
Total Output
Power
Backplane Plus
Auxiliary
(Watts)
70 W
60 W
50 W
40 W
30 W
20 W
10 W
0 W
0 W 20 W 40 W 60 W 80 W 100 W 120 W
22 W
10 W
6 W
Output Power (Watts)
112 W
6 W
16 W
Input Power (Watts)
Publication 1768-IN001B-EN-P - July 2006
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