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Fisher
r
646 Electro‐Pneumatic Transducer
Contents
Introduction
1
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Scope of Manual
1
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Description
3
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Specifications
4
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Educational Services
4
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Installation
4
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Hazardous Area Classifications and
Special Instructions for “Safe Use” and
Installation in Hazardous Locations
5
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CSA
5
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FM
6
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ATEX
6
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IECEx
7
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Mounting
8
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Pneumatic Connections
9
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Supply Pressure Requirements
9
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Diagnostic Connections
10
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Vent
10
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Electrical Connections
10
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Operating Information
12
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Calibration
12
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Equipment Required
12
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Calibration Procedure
12
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Principle of Operation
13
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Maintenance
14
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Troubleshooting
14
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Converter Module Replacement
15
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Relay Maintenance
16
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Figure 1. Fisher 646 Electro‐Pneumatic Transducer
Mounted on a Sliding‐Stem Actuator
W6783‐1/IL
Parts Ordering
18
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Parts Kits
18
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Parts List
18
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Loop Schematics
22
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Introduction
Scope of Manual
This instruction manual provides installation, operation, maintenance, and parts ordering information for the Fisher
646 transducer. Refer to separate manuals for instructions covering equipment used with the transducer.
Do not install, operate or maintain a 646 electro‐pneumatic transducer without being fully trained and qualified in
valve, actuator and accessory installation, operation and maintenance.
To avoid personal injury or property damage it
is important to carefully read, understand, and follow all of the contents of this manual, including all safety cautions
and warnings.
If you have any questions about these instructions, contact your Emerson Process Management sales
office before proceeding.
Instruction Manual
D101351X012
646 Transducer
January 2015
