Category: Industry Trends

• For Foundation™ fieldbus networks in hazardous areas

• Complete enclosure systems for 12 intrinsically safe spur connections

• Mount in Zone 1 (gas) or 21 (dust) with spurs connected into Zone 0

• Compatible with FISCO and Entity-certified fieldbus instruments

• Compact, modular construction

• Ergonomic mechanical design

• Pluggable system components, without ‘gas free’ constraints

• Optional, integrated surge protection for trunk and spurs

• Optional, integrated Isolation Switch for Trunk

The 9373-FB3 is a third-generation product, in a successful

range of Eaton Fieldbus Barrier Systems.  The field-mounted

enclosure contains a barrier that receives power and

FOUNDATIONTM fieldbus H1 communications via a non

intrinsically safe trunk and converts this to a number of

galvanically isolated, intrinsically safe, spur connections.

The trunk terminals are implemented as increased safety

(Ex e) and the spur terminals as intrinsically safe (Ex ia) for

connection to IS fieldbus instruments in IIC, Zone 0 hazardous

areas.  The spur connections are compatible with both FISCO

and Entity-certified field instruments.

MTL4546S ISOLATING DRIVER

for 4–20mA HART® valve positioners with line fault detection and long field lines

The MTL4546S accepts a 4/20mA floating signal from a safe-area

controller to drive a current/pressure converter (or any other load up to

710Ω) in a hazardous area. For HART valve positioners, the module also

permits bi-directional transmission of digital communication signals.

Process controllers with a readback facility can detect open circuits in

the field wiring: if these occur, the current taken into the terminals drops

to a preset level. The reduced maximum open-circuit voltage permits

the use of longer field lines compared to MTL4546

SPECIFICATION

See also common specification

Number of channels

One

Location of I/P converter

Zone 0. IIC, T4–6 hazardous area if suitably certified

Div. 1. Group A, hazardous location

Working range

4 to 20mA

Digital signal bandwidth

500Hz to 10kHz

Maximum load resistance

710Ω (14.2V at 20mA)

Minimum load resistance

90Ω

Output resistance

> 1MΩ

Under/over range capability

Under range = 1mA

Over range = 24mA (load ≤ 520Ω)

Input and output circuit ripple

< 40µA peak-to-peak

MTL4546/C/Y – MTL5546/Y ISOLATING DRIVER

for 4–20mA HART® valve positioners with line fault detection

The MTLx546 accepts a 4/20mA floating signal from a safe-area controller

to drive a current/pressure converter (or any other load up to 800Ω) in a

hazardous area. For HART valve positioners, the module also permits

bi-directional transmission of digital communication signals. Process

controllers with a readback facility can detect open or short circuits in

the field wiring: if these occur, the current taken into the terminals drops

to a preset level. The MTL4546C and the MTLx546Y are very similar

to the MTLx546 except that they provide open circuit detection only

(i.e. no short-circuit detection).

Operation and configuration

LED indicator functions

The EAFR-101C contains 16 indication LEDs .  A user definable text

pocket can be slid in under the label for identifying each LED func

tion (except POWER and ERROR LEDs) .  LEDs are located at the

front plate of the relay for clear viewing without a need for opening

doors .

During power up, the relay performs an LED test .  All LEDs are

turned on for two seconds and then off .  Only the blue POWER LED

will remain on .  After powered up, the relay goes into protection

mode in 50 ms even while the LED test is being performed .

During normal operation, the blue power LED is ON, as are any CB

open/close status LED’s for connected CB’s .

The sensor LEDs are off during the inactive condition .  If  a point arc

sensor is activated, the corresponding sensor channel LED will turn

on if the activation is longer than 1 .5 ms .  The sensor LED activation

function is latched (steady light) .  To clear the LED, the “SET” button

should be pressed .

In case of a loose sensor wire and binary input wires or configura

tion mismatch (new sensor attached without running auto-configu

ration system setup (see Section 3 .3 .1) situation, the corresponding

LED for that sensor will start flashing and the ERROR LED will

activate .

The Binary I/O LEDs indicate the I/O-line status .  If any of the lines

become active for more than 1 .5 ms, the corresponding LED will

turn on (latch) .

In a trip situation, the corresponding trip LED will turn on .  Trip

outputs are controlled by the dipswitch settings (see Section  3 .5) .

All activation and trip indication LEDs are latched, even if the

dipswitch setting is in the non-latched mode .  They have to be

cleared by pushing the “SET” button .

LED indications are stored in non-volatile EPROM memory for iden

tifying the trip information in case the auxiliary power is lost .  When

re-powering the relay after power supply loss, the actual LED status

can be visualized from the front of the relay

EAFR-101C features

The EAFR-101C is a multipurpose arc flash protection relay that can

receive light from four different channels of light point sensors and

can be applied for variety of applications .  The EAFR-101C can be

used as a stand-alone relay or as part of a more complex arc protec

tion system through the binary bus .

Main features of EAFR-101C:

• (110-220) Vac / (125-250) Vdc  auxiliary  power  supply;

• (18-72) Vdc optional power supply;

• Four arc point sensor channels (S1. S2. S3. and S4);

• Six binary inputs (BI1. BI2. BI3. BI4. BI5. and BI6) nominal voltage

of 24 Vdc;

• Three normally open trip relay outputs with direct trip circuit rated

contacts (T1. T2. and T3);

• One normally open electronic lock-out trip relay with direct trip

circuit rated contacts (T2);

• Two 24 Vdc binary outputs (BO1 and BO2);

• One system failure relay, form C output (SF);

• 16 indication LEDs; and

• One push-button (SET)

General

The Eaton arc flash relay 101C (EAFR-101C) is a sophisticated

micro-processor based arc flash protection relay including complete

self-supervision functionality .  It is designed to minimize the damage

caused by an arcing fault (arc flash) by sensing light from the point

sensor and acting to trip the circuit breaker sourcing the fault

current .  The EAFR-101C complete system self-supervision function

provides the highest level of dependability by continuously monitor

ing all internal system functions along with external connections .

The EAFR-101C is designed according to the latest protection relay

standards and is therefore suitable for installations in rough environ

ments, such as utility, traditional or renewable power plants, off

shore, marine, oil and gas, mining, steel, or any other heavy industry

applications .  It is also well suited for commercial and institutional

electrical systems .  The EAFR-101C is suitable for either medium

voltage or low voltage switchgear and motor control center applica

tions in both new and retrofit installations .

Introduction

Read these instructions carefully and inspect the equipment to

become familiar with it before trying to install, operate, service, or

maintain it .

Electrical equipment should be installed, operated, serviced, and

maintained only by qualified personnel .  Local safety regulations

should be followed .  No responsibility is assumed by Eaton for any

consequences arising out of the use of this material .

Eaton reserves right to changes without further notice .

Abbreviations

CB – Circuit breaker

CBFP – Circuit breaker failure protection

EMC – Electromagnetic compatibility

EPROM – Erasable programmable read only memory

HW – Hardware

LED  – Light emitting diode

LV  – Low voltage

ms – Millisecond

MV – Medium voltage

NC – Normally closed

NO – Normally open

PMSG – Permanent magnet synchronous generator

Rx – Receiver

SF –    System failure

SW – Software

Tx – Transceiver

uP2– Microprocessor

Assessment of Functional Safety

The design features and the techniques/measures used to prevent systematic faults are suitable for the use of

the MTLx546 and MTLx549 modules in safety functions up to SIL2 in a simplex architecture.

The hardware assessment shows that MTLx54x analogue output modules:

•  have a hardware fault tolerance of 0

•  are classified as Type A devices (“Non-complex” component with well-defined failure modes)

•  have no internal diagnostic elements

It should be recognised that the systematic capability of the products limits their application to SIL2 loops.

It is important that the effect of electromagnetic interference on the operation of any safety function is reduced

where possible. For this reason it is recommended that the cable connections from the logic solver to the isolator

modules be a maximum of 30 metres and are not exposed to possible induced surges, keeping them inside a

protected environment.

Similarly, operation of the equipment outside of its environmental ratings induces component stress and

temperature above the normal ambient of 60°C is to be avoided to ensure required performance.

Selection of product and implications

The analogue signal levels employed by the MTLx54x are within the operating range of 4-20mA under normal

conditions.

If the wiring between the isolator and field device are open circuit then the line-fault detect (LFD) operation of the

isolator forces the current taken into the input terminals to fall to a low value, which is less than the expected under

range value of 3.6mA. The MTLx546 and MTLx549 models also detect when the resistance in the field wiring is less

than fifty ohms indicating a short circuit condition, and this also is reflected into a low input current value.

This diagnostic aspect can be used by logic solvers that include a readback facility to monitor the output current from

their output cards or modules. Thus the ability to detect that the actual current being passed is not the desired value

can be used to determine the health of the instrument function. The same condition of the actual loop current falling

to a low level will also occur if the wiring between the logic solver and the isolator is open circuit.

Using a field device and logic controller, as defined in section 2. with an MTLx54x then a system-loop can be

implemented that applies functional safety together with intrinsic safety to meet the requirements of protection

against explosion hazards. Note that the transfer of HART communications through the isolator is not considered as

part of the safety function of the isolator.

It should be recognised that the systematic capability of the products limits their application to SIL2 loops.

It is important that the effect of electromagnetic interference on the operation of any safety function is reduced

where possible. For this reason it is recommended that the cable connections from the logic solver to the isolator

modules be a maximum of 30 metres and are not exposed to possible induced surges, keeping them inside a

protected environment.

Similarly, operation of the equipment outside of its environmental ratings induces component stress and

temperature above the normal ambient of 60°C is to be avoided to ensure required performance.

Associated System Components

There are many parallels between the loop components that must be assessed for intrinsic safety as well as

functional safety where in both situations the contribution of each part is considered in relation to the whole.

The MTLx54x module is a component in the signal path between safety-related actuators and safety-related

control systems.

The current to pressure converter, valve positioner, or other field device, must be suitable for the process and

have been assessed and verified for use in functional safety applications as well as its certification for hazardous

area mounting.

The safety system PLC shall have a current output with a normal operating range of 4-20mA but capable of

working over the extended range of 3 to 22mA for under- and over-range. Such controllers will normally also

include a readback facility to enable the detection of open or short circuits in the wiring.

The transmission of HART data is not considered as part of the safety function and is excluded from this analysis.