Select protection method(s), Match field devices and i/o modules – Rockwell Automation 1797-OE8 FLEX Ex Analog Modules User Manual User Manual

Page 69

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Publication 1797-6.5.1 - May 2005

Applying FLEX Ex Analog I/O Modules 6-3

Select Protection
Method(s)

Although the FLEX Ex system primarily uses the Intrinsic Safety protection
method, the system uses all methods listed below.

Match Field Devices
and I/O Modules

You must match field devices and I/O modules for your application to
function properly. Consider the following:

• Verify field device and I/O module operational characteristics

• Match entity parameters of field devices and I/O modules

P/I Analog Transmitter Functional and IS Parameters

The figure below shows a typical pressure to current analog transmitter. Two
types of characteristics are shown, functional and IS.

Table 6.1 Protection Methods for Hazardous Applications

Protection Method

Designation

1

Method of Achieving
Protection

Intrinsic Safety

EEx

ia

/EEx

ib

Energy Limiting

Encapsulation

EEx

m

Segregation

Increased Safety

EEx

e

Refined Mechanical Design

Flameproof

EEx

d

Containment

1

In the Non-Incendive protection method, n: used locally in the United States and United Kingdom.
In the Intrinsic Safety method, ia: Zone 0, 1, 2 & ib: Zone 1, 2

IMPORTANT

As not all protection methods are applicable for all
locations, consult local certifying agencies to determine
acceptable protection methods for your application.

600

250

10.5

16.4

24.7

42

4-20mA IS

P/I Transmitter

10.5-42V operate

EEx ia IIC T4

Ui=30V

Ii=165mA

Ci=22.5nF

Li=730uH

Power Supply Voltage

External

Load

Resistance

41662

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