Rockwell Automation 1797-PS2N2 User Manual

Installation Instructions

FLEX Ex Power Supply

Catalog Number 1797-PS2N2

Top ic Page

Important User Information 2 About the Power Supply 3 Understanding System Planning 4 Electrostatic Charge 6 Outputs 6 Mount the 1797-PS2N2 Power Supply 7 Customer Connections 8 1797-PS2N2 Power Supply Mounting Dimensions and Terminal

Base Assignments Repair 9 Specifications 10 Certifications 11 UL, C-UL I/O Entity Parameters 13 FM I/O Entity Parameters 16 Ferrite Beads 19

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2 FLEX Ex Power Supply

WARNING

IMPORTANT

ATTENTION

SHOCK HAZARD

BURN HAZARD

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 we use notes to make you aware of safety considerations.

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.

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 identify a hazard, avoid a hazard, and recognize the consequence

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Labels may be on or inside the equipment to alert people that dangerous voltage may be present.

Labels may be on or inside the equipment to alert people that surfaces may be dangerous temperatures.

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ATTENTION

This equipment is considered Group 1, Class A industrial equipment

1797-PS2N2

40468

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 enclosed equipment. It should not require additional system enclosure when used in locations consistent with the enclosure type ratings stated in the Specifications section of this publication. Subsequent sections of this publication may contain additional information regarding specific enclosure type ratings, beyond what this product provides, that are required to comply with certain product safety certifications.

About the Power Supply

FLEX Ex Power Supply 3

The power supply is an essential component in the operation of an intrinsically safe system. It must isolate the unsafe incoming power from the control system and limit the available energy to IS-safe levels.

No other power source is needed to operate any components attached to the FLEX Ex system in the hazardous area. Power for valves, actuators, or transmitters come from the FLEX Ex modules.

The 1797-PS2N2 is a 24V dc in/quad-Ex dc out power supply in an explosion-proof enclosure with 1 in. conduit pipe-thread input and output terminators.

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4 FLEX Ex Power Supply

Features include the following:

 24V dc supply source  Four channels, 8.5 W output each channel  Dual power feeds for source input redundancy  Outputs are IS galvanically isolated from the source  All channels are independently IS limited

Understanding System Planning

Part of system planning is determining what modules are needed for the application, how many power supplies are needed, how to best partition the system, and where to locate the system cabinets.

A key task in the development cycle is determining the number of power supply outputs (thus power supplies) you will need. In the following example, you will need eleven power outputs if you are using the fiber hub, which

requires 8.5 W.

Modules Requires Modules Requires

Fiber hub 8.5 W Two thermocouple inputs 1.6 W each

Two ControlNet adapters Two analog inputs 7.5 W each Three NAMUR digital inputs 2.8 W each Two analog outputs 6.3 W each Two counter inputs 4.25 W each

8.5 W each Two digital outputs 7.5 W each

Each power supply has four independent IS-power outputs capable of 8.5 W each. In the above example, we required 11 IS-power outputs so three power supplies were sufficient.

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IMPORTANT

IS Pwr

Safe Area

Hazardous Area

1797 power supply

ACNR

Spare

IE8 OE8 IRT8 Spare Spare IJ2 IJ2

ACNR OB4 OB4D IBN16 IBN16 IBN16 IE8 IRT8 OE8

RPA RPFM RPFM

IS 1797 I/O

IS 1797 Fiber Hub

IS Pwr IS Pwr IS Pwr

IS Pwr IS Pwr IS Pwr IS Pwr

41306

Unsafe



Power



Entrance

Spare

Unsafe



Power



Entrance

Unsafe



Power



Entrance

FLEX Ex Power Supply 5

The total number of power supplies needed depends on the modules used and the total system configuration. The following illustration shows how this example may be configured.

Even though modules may be supplied with power from the same power-supply output channel, galvanic isolation in the module provides module to module galvanic isolation. Depending upon the module type, galvanic isolation (channel-to-channel within the module) may or may not be provided. See the module’s specifications for more information.

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IMPORTANT

41307

Make certain that you only connect intrinsically-safe power supplies to other intrinsically-safe system modules or adapters to maintain the integrity of the intrinsically-safe backplane.

Electrostatic Charge

Protect the system against electrostatic charge. Post a sign near this module. 

WARNING Avoid electrostatic charging. ADVERTÊNCIA! PREVENIR CONTRA O ACÚMULO DE CARGA

ELETROSTÁTICA.

For your convenience, a sign that can be cut out and posted is included on the last page of these installation instructions.

Outputs

When using an intrinsically-safe electrical apparatus according to NEC 2002 or CEC 2002, the appropriate USA or Canadian codes must be followed.

The channels in the power supply are electrically connected to each other and have a common +V line.

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You cannot interconnect lines because of the intrinsic safety requirements.

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