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INM7700-6   

Jan 2010

2.3

MTL7700 Series – accessories

MTL7700 Series barriers mount directly onto DIN-rail. A
comprehensive selection of mounting, tagging, power and earthing
accessories is available. Installation details are given in section 4.3.

Essential accessories

The following are usually considered essential for mounting and
earthing MTL7700 Series barriers:

DIN-rail (eg, THR2 or THR7000)
Insulating spacers (eg, ISP7000)
Earth terminal (eg, ETL7000)

The tagging systems for individual modules and columns of barriers
are described here. They are shown below under Tagging
accessories for columns of barriers.

Mounting accessories (figure 2)

THR2

Standard DIN-rail, 35 x 7.5mm, (in 1m lengths)

THR7000

Nickel-plated DIN-rail, 35 x 7.5mm, for use in 
potentially corrosive atmospheres (in 1m lengths)

ISP7000

Insulating spacer: attaches to the base of a DIN-
rail to isolate the IS earth from a structural earth

Tagging accessories for individual barriers (figure 2)

TH7700

Tag holder for mounting on the top of an 
individual barrier

Tagging accessories for columns of barriers (figure 2)

TAG57

Tagging strips for mounting over a column of 
barriers, for marking barrier locations. Supplied 
(with labels) in 1m lengths for cutting to size.

TGL7700

Spare labels for use with TAG57 tagging strips: 
0.5m strips, supplied in sets of 10.

IMB57

Tagging strip supports. Two needed for each 
tagging strip. It can also be used as centre 
support by breaking off the top end tab. 

Power accessories (figure 3)

BPL7700

Power link for feeding 24V dc to a maximum of 
40 barriers in a single column from an MTL7798
power feed module or MTL7799 Dummy 
module.

Earthing accessories (figure 3)

ETL7000

Earth terminal providing connections for 
routeing the IS earth from the DIN-rail to an 
appropriate plant earth. Two recommended for 
each length of DIN-rail.

TAG57

TGL7700

ERB57O

IMB57

ETL7000

ISP7000

TH7700

Figure 2: 

MTL7700 Series mounting and tagging accessories

Table 1: 

MTL7700 Series Key barriers

Type

Application

Key barriers

MTL

Analogue Resistance temperature detectors

7755ac

input

Thermocouples, ac sensors

7756ac

(low-level)

7760ac

Analogue Controller outputs, one line earthed

7728+

output

Controller outputs, neither line earthed

7787+

dc power supply

26V

20-35V

Analogue Transmitters, 2-wire, 4–20mA

7787+

7706

input 

(high-level)

Digital Switches

7787+

7707+

(on/off)

7741-44

input

Digital Solenoids, 

alarms, 

LEDs

7728+

7707+

(on/off)

output

www.calcert.com

[email protected]

1.888.610.7664

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Summary of Contents for MTL770 Series

Page 1: ...Instruction Manual INM7700 MTL7700 Series Shunt diode safety barriers www calcert com sales calcert com 1 888 610 7664 0 5 10 15 20 25 30...

Page 2: ...ii INM7700 6 Jan 2010 www calcert com sales calcert com 1 888 610 7664 0 5 10 15 20 25 30...

Page 3: ...h 7 5 4 Connections to dummy barriers 9 6 MAINTENANCE 9 6 1 General 9 6 2 Routine inspection 9 7 FAULT FINDING 10 7 1 Introduction 10 7 2 Power supply check 11 7 3 Barrier resistance test 11 8 EQUIPME...

Page 4: ...INM7700 6 Jan 2010 iv www calcert com sales calcert com 1 888 610 7664 0 5 10 15 20 25 30...

Page 5: ...are available either from the company website www mtl inst com or on request from your local MTL office 2 DESCRIPTION 2 1 Introduction MTL7700 Series fourth generation intrinsically safe shunt diode s...

Page 6: ...ers for marking barrier locations Supplied with labels in 1m lengths for cutting to size TGL7700 Spare labels for use with TAG57 tagging strips 0 5m strips supplied in sets of 10 IMB57 Tagging strip s...

Page 7: ...en length of DIN rail allow space length for a Barrier packing pitch 12 6mm b ETL7000 earth terminals 10mm each minimum of two c IMB57 tagging strip support 16 0mm minimum of if specified two d ISP700...

Page 8: ...recommendations contained in the relevant sections of IEC 60079 14 for the gas group temperature classification and area classification required 2 4 1 6 2 Make sure the barriers are of the correct typ...

Page 9: ...end of a column of barriers to provide redundancy and to simplify earth testing procedures WARNING Apart from rare occasions when the mounting surface carries the IS earth the ONLY method of providin...

Page 10: ...bly figure 12 identifies the location of individual barriers ensuring that they are replaced correctly after removal for maintenance or testing Once installed the tagging strip pivots upwards to provi...

Page 11: ...vidual barriers and applications 5 2 3 Bussed Power applications and connections When a number of barriers use a common power supply the optional power link BPL7700 can be used Typical applications in...

Page 12: ...or normally copper wire with a cross sectional area of at least 4mm2 12AWG must be connected between ETM7 earth terminals located at each end of the rail and the spare terminals on the ETL7000 termina...

Page 13: ...educes interference problems but is not essential for safety reasons f In general the use of barriers in all measurement leads reduces the possibility of earth circulating currents causing measurement...

Page 14: ...ck However when fault finding is necessary it must only be undertaken after checking with plant personnel responsible for safety that it is safe to proceed The fault finding procedures described in th...

Page 15: ...by using an MTL7760ac barrier as shown in figure 21 This permits the thermocouple output to be measured without needing special authorisation to use uncertified thermocouple test equipment As it is se...

Page 16: ...rehensive testing requires specialised equipment beyond the scope of on site tests However an effective test which will confirm that the unit is operating correctly is shown in figure 24 Ammeter 1 mea...

Page 17: ...he output contacts according to Table 3 3 4 1 2 MTL7742 5 6 7 8 Bussed Power 24V Vs Vs 2K Figure 27 Test circuit for MTL7742 3 4 1 2 MTL7745 5 6 620W 10kW 24V Bussed Power Line Fault Output Vs Vs Figu...

Page 18: ...e the expected reading across the diode chain can be determined BARRIER DATA MULTIMETER TESTS CONSTANT CURRENT TESTS MTL Safety End to end Diode Diode Terminal Terminal model Description Resistance Te...

Page 19: ...7 Dual channel ac barriers BARRIER DATA MULTIMETER TESTS CONSTANT CURRENT TESTS MTL Safety End to end Diode Diode Terminal Terminal model Description Resistance Test Test Voltage Voltage No ve ve 10 A...

Page 20: ...fz x 2 26 6 27 4 26 7 27 6 7787 ch2 28 0 9V 26 Vfz x 2 26 6 27 4 26 7 27 6 7787P 28 237 119 241 253 Vfz x 3 26 4 27 4 26 5 27 6 7787P ch2 28 0 9V 26 Vfz x 2 26 6 27 4 26 7 27 6 7789 38 300 93 614 651...

Page 21: ...ceiver Figure A6 Low level analogue inputs RTD s Figure A2 2 wire transmitters with 250 conditioning Hazardous Area Safe Area 3 4 1 2 MTL7760ac MTL7765ac MTL7778ac Recorder Controller Data logger Comp...

Page 22: ...3 4 1 2 MTL7745 5 6 620 10k 22 9 30V LFD COM CH 1 Power Bus Figure A10 Single channel switch proximity input with Line Fault Detect Hazardous Area Safe Area 3 4 1 2 MTL7789 7 8 5 6 Power 26V Power 26V...

Page 23: ...www calcert com sales calcert com 1 888 610 7664 0 5 10 15 20 25 30...

Page 24: ...91 0 44 24501660 24501857 Fax 91 0 44 24501463 E mail sales mtlindia com MTL Italia srl Via Cant 11 I 20092 Cinisello Balsamo MI Italy Tel 39 0 2 61802011 Fax 39 0 2 61294560 E mail info mtl inst it M...

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