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MTL700 and 700P Series shunt

1. Model 1 2 Max end 3 4 5 6 No Safety description Polarities Application Basic circuit to end Vwkg Vmax Fuse available Hazardous Safe resistance TO 1 uA rating MTL v Q mA ac Q v v mA 702 25 200 125 y Transmitters 35 See 3 3 1705 28 300 93 Y Transmitters See 3 3 2 zx 35 Additional 706 28 300 93 Transmitters Additional E 35 spec 707 28 300 93 y Switches specification 35 28 diode 50 708 28 300 93 y Solenoids alarms LEDs 35 50 710 10 50 200 V vV y 6V de amp AV ac systems ed 6 85 6 0 6 96 50 715 15 100 150 y y 12V systems 155 12 0 13 0 100 722 22 150 147 y y 18V de systems 185 19 0 20 2 50 728 28 300 93 y Controller outputs solenoids o y t 340 25 5 26 6 50 728 28 300 93 V oy Transmitters 4 2 340 25 56 26 64 50 751 1 10 100 y Active de amp ac sensors 3 i 20 0 3 2 0 250 1 10 100 low impedance receivers 9 20 0 3 2 0 250 755 3 10 300 y Resistance temperature ac 18 09 0 6 3 6 250 3 10 300 detectors 18 09 0 6 3 6 250 oy o 4 2 758 7 5 10 750 y y Gas detectors 18 6 0 7 0 200 7 5 10 750 e Ove v6 t 18 6 0 7 0 200 761 9 90 100 y 45 6 0 7 5 100 9 90 100 45 6 0 7 5 100 764 12 1k 12 NN y Strain gauge bridges 1075 10 0 19 78 50 12 1k 12 1075 10 0 10 78 50 766 12 150 80 y 85 10 0 11 2 50 12 150 80 O O 85 10 0 11 2 50 767 15 100 150 y y 12V de systems 4 20V 796 2 5
2. 475 ONIJIM VIIV SNOGIVZVH ONIAIM V33V 34VS Knockout hole 25 lt e e A eh J y gt del fele eloh de N s A lla e A ma n 7 m EC 198 E J i z HO ele XB m O Y 25 x 97 f 2 P Mir MM 125 ES i a E 100 gt AE SS 175 e N zv N j K TAA are used Figure 6 Enclosure dimensions mm 200 MT12 Fixing lugs for MT12 DN The screw on fixing lugs can be positioned as shown left Add 5mm to depth if fixing lugs A type n approved steel enclosure is available in the range for protecting up to 20 barriers in Zone 2 areas The dimensions and specifications of the enclosures are given in table 7 and figure 6 respectively 5 1 Fitting the barriers into the enclosure Each enclosure is supplied ready fitted with all the necessary accessories to allow immediate installation of barriers To fit the barriers remove the enclosure s lid by releasing the captive screws the MT20N enclosure s lid is removed by also lifting it off its two hinges Temporarily unclip the TGS7 tagging strip not fitted on model MT2 then simply bolt each barrier via its two earth studs to the section of busbar provided tightening all nuts to a to
3. INM700 10 June 2005 16 7 6 Entity concept parameters for MTL70O Series FM Table 10 Entity concept parameters for 1 channel MTL7OO barriers figure 28 of an MTL728 Barrier Voc Isc Ca La model no MTL V mA pF mH 702 25 11 125 0 17 2 2 705 28 1 93 0 12 4 0 706 28 1 93 0 12 4 0 708 28 1 93 0 12 4 0 710 10 03 189 3 0 1 0 715 15 06 146 0 7 1 4 722 22 08 146 0 2 1 4 728 28 12 93 0 12 4 0 One channel of an MTL779 can be used in place Hazardous location Class Div 1 Groups A B C D Class ll Div 1 Groups E G Class Ill Hazardous location equipment see note 1 after table 21 Ground 10 max F Non hazardous location 1 channel barriers Figure 28 channel barrier connections 1 channel barrier table 21 Non hazardous location devices V 250V max see note 2 after Note one channel of an MTL779 may be used in place of an MTL728 Table 11 Entity concept parameters for 2 channel MTL700 barriers with no ground return figure 29 and separate ground returns for each channel figure 30 Figure 29 Figure 30 Barrier model No Voc Ise Ca La Voc Ise Ca La MTL v mA pF mH v mA pF mH 751 1 92 89 1000 4 5 0 96 89 1000 4 5 755 5 92 296 1000 0 4 2 96 296 1000 0 4 758 8 5 821 6 0 0 05 760 10 03 97 3 3 5 10 3 194 3 0 0 9 761 18 08 99 0 40 3 5 9 04 99 3 1 3 5
4. IH Figure 40 MTL705 and706 test circuit 11 5 Tests for the MTL707 and 707P Since these units incorporate a built in protection circuit they have to be tested in a different manner to an ordinary shuntdiode barrier Referring to figure 41 set the transmitter simulator to various currents in the range 4 to 20mA and check that the ammeter reads approximately the same value Then set the simulator to 20mA checking the voltage between terminals 1 and 2 lt 9V for the MTL707 and 4 3V for the MTL707P and between terminals 2 and 4 3 1V for the MTL707 and 1 9V for the MTL7O7P 4 20mA 20 to 35V dc Transmitter simulator Figure 41 MTL707 and 707P ied circuit 11 6 Tests for the MTL708 This unit of similar design to the MTL7O7 is tested in the same manner Referring to figure 41 set the transmitter simulator to 20mA and check that the voltage between terminals 1 and 3 is less than 8 9V 20mA 20 to 4 35V dc Transmitter simulator Alo Figure 42 MTL708 test circuit 11 7 Test tables These tables describe the tests for models MTL710 to 796 inclusive The figures adjacent to the diode symbols indicate the number of forward biased diodes used in the barrier chain Using a multimeter diode test function and referring to the diode voltage drop figures given in section 9 approximately 0 6V for each Zener diode and 0 3V for each Schottky
5. the mounting bracket 1 to the insulating block 2 through the This is the hazardous side of the assembly Slide the smaller 4mm four M4 holes terminal clamps 12 onto the earth rail 4 and mount the earth rail onto the earth rail mounting brackets 3 with the earth rail clamps b The insulating block 2 is provided to keep the IS earth termi 10 Fit the larger 16mm terminal clamps 11 onto the longer pro nated on the mounting bracket 1 separate from a structural truding lengths of the earth rail mounting brackets 3 two being earth but if the mounting surface is insulated then the insulating mounted on one bracket and one on the other These terminals are block may not be necessary used for connecting the IS earth c Use the 4mm terminal clamps 5 to connect the IS earth and ter d e only de the smaller 4mm been clamps 12 onto the e shorter protruding lengths of the earth rail mounting brackets 3 and minating cable screens to the mounting bracket nisl E e larger 16mm terminal clamps 11 onto the longer protruding lengths In both cases two are mounted on one bracket and one 6 5 MK5 MK12 and MK20 mounting kits on the other The smaller terminal clamps serve the same purpose 6 5 1 MKS parts list as the earth rail and clamps for the MK1 2 and MK20 while the func Ms tion of the larger terminal clamps is the same for all three kits Part number Description Quantity e To mount the insulating mounting blocks
6. 1 Current nO limit E 0 35V EE DS 50mA max FED alarm l isolenoid out 1 mA max 1 ete i Figure 3 MTL708 basic circuit gt i e wO 3 1 po t O 35V 50mA max mA max l out 1 i e gt gt o 4 50mA 2 Figure 3 MTL707 basic circuit see Table 4 for MTL7O7P basic circuit H ae 9 s E ae el 25 0 7 5 155 7 5 Non hazardous Hazardous area safe area __ 22 terminals A EME HE terminals 61 5 49 2 lt 85 0 gt lt 14 2 gt lt 93 5 gt Figure 5 Barrier dimensions in mm 3 3 4 MTL708 additional specification Supply Voltage Vs 10 to 35V dc positive w r t earth Output current lout Up to 35mA available Maximum voltage drop at 20 C current not limited lou X 3700 1 5V terminals 1 to 3 Supply current lou IMA maximum Vs 26V Limited at 50mA Vs gt 28V or low load resistance INM700 10 June 2005 Table 3 Basic circuits and specifications for MTL70O Series barriers for notes 1 to 7 see 3 2 1 Terminology
7. 300mA 307 Int safe connections to Cl 1 Div 1 Gps A B C D CI II Div 1 Gps E G CI III Div 1 Dwg SCI 88 Voc lt 5 92V Isc lt 296mA Ca lt 1000F La lt 0 4mH Vm lt 250V r m s BASO1ATEX7202 Um 250V O1 Safe Haz Approved Int safe connections to Cl I Groups A B C D Cl II Groups E F G Cl III See Drawing SCI 193 for connections Voc lt 2 96V Isc lt 296mA Ca lt 346uF La 0 4mH La Ra lt 704H Q 404 LISTED Made by 73P6 MTL Instruments Pvt Ltd Chennai India Vmax lt 250V r m s C 1180 Model No Q mA MTL702 200 125 MTL706 300 93 MTL707 300 93 Table 11 Rm MTL7OO Series MTL707P 164 170 Safety parameters E z MTL708 300 93 MTL710 50 200 MTL710P 33 300 MTL715 100 150 MTL715P 50 291 MTL722 150 147 MTL722P 101 213 MTL728 300 93 MTL728P 234 119 MTL729P 164 170 MTL751 10 100 10 100 MTL755 10 300 10 300 MTL758 10 750 10 750 MTL761 90 100 90 100 MTL761P 350 25 350 25 MTL764 k m kk 12 MTL766 150 80 150 80 MTL766P 75 157 75 157 MTL767 100 150 100 150 MTL768 150 147 150 147 MTL779 300 93 300 93 MTL796 300 87 390 51 MTL760 50 200 50 200 MTL765 100 150 100 150 MTL772 300 73 300 73
8. 5 check that the swing 1 DIN rail 156mm 1 nuts forming part of each unit are turned away and locate the units 2 Earth busbar 29mm 1 on the DIN rail 1 Tighten the screws accessing the swing nuts to 3 Earth rail mounting brackets 2 pivot them underneath the edge of the DIN rail so securing the 5 Insulating mounting block 2 blocks to the rail ldbel assembly l f Complete the installation by adding the tagging facilities First agging strip seal 1 ho label to add identikeationih i d ih 8 M4 Nyloc nuts A remove fi e label to a i entitication then replace an Secure witl 9 M her 4 the clic rivet Second clip the tag label assembly 6 onto the instal 11 Terminal clamps 16mm 3 lation with the lugs on top of each insulating mounting block 5 P Third seal the tagging information to the installation by fitting the 12 Terminal clamps 4mm 3 d 9ging y NING tagging strip seal 7 through the hole in the tagging strip and the vertical slot in the mounting block The tagging strip can be unclipped from one side only and hinged open to provide access to the mounting studs and terminals of the barriers when required 7 WIRING INSTALLATION Before undertaking the installation of MTL700 700P Series barriers section 4 of this manual should be read before commencing the instructions contained in this section All instructions in this section apply to barriers mounted in MTL enclosures or as unenclosed systems Figure 24 should be referred to fo
9. MTL778 600 47 600 47 MTL786 gt E a MTL787 300 93 E MTL787S 300 93 E E MTL7875P 234 119 E MTL788 300 93 50 200 MTL788R 300 93 50 200 MTL791 51 216 51 216 MTL799 Model No V Q ma MTL7122 22 150 147 MTL7028 28 300 93 MTL7128 28 300 93 MTL7128P 28 234 120 MTL7129P 28 164 171 MTL7028 28 300 93 MTL7128 28 300 93 MTL7162 10 50 200 10 50 200 MTL7 164 12 1k 12 12 1k 12 MTL7167 15 100 150 15 100 150 MTL7096 26 300 87 20 390 52 MTL7196 26 300 87 20 390 52 MTL7087 28 300 93 28 EL MTL7187 28 300 93 28 95 MTL7087P 28 234 120 28 gt MTL7187P 28 234 120 28 gt MTL7055ac 3 10 300 3 10 300 MTL7056ac 3 10 300 3 10 300 3 10 300 MTL7261ac 9 90 100 9 90 100 MTL7061Pac 9 350 26 9 350 26 MTL7161Pac 9 350 26 9 350 26 MTL7264ac 12 Tk 12 12 1k 12 MTL7066Pac 12 75 160 12 75 160 MTL7166Pac 12 75 160 12 75 160 MT7060ac 9 75 120 9 75 120 MT7160ac 9 75 120 9 75 120 MT7265ac 15 100 150 15 100 150 MI7278ac9 28 600 47 28 600 47 MT71064 28 300 93 MT72064 28 300 93 MT7207 28 300 93 28 5 MT
10. Warning labels bearing the words Intrinsically Safe System TAKE 140 65 Intrinsically Safe System 100 40 TAKE CARE A dm TECHNOLOGY Ex i Y Figure 16 Take Care instrinsic safety label ISL3 or ISL7 CARE are available for attaching to enclosures or in areas where intrinsically safe systems and equipment are in use Plastic labels with adhesive fronts ISL7 for attaching to the insides of transparent enclosure lids and metal labels with adhesive backs ISL3 are 175 i Figure 17 Torque spanner TQS7 available Figure 18 Surface mounting clips SMC7 INM700 10 June 2005 6 1 11 Torque spanner TQS7 For tightening barrier mounting studs The spanner is set to a torque of 2 3Nm 20lb in and fitted with a 7mm A F socket 6 1 12 Surface mounting clips SMC7 These clips are used for mounting small numbers of barriers on flat surfaces where it is not convenient or possible to use busbars Supplied in bags of ten two clips needed per barrier Figure 19 DIN rail mounting kit DRK700 6 1 13 DIN rail mounting kit DRK700 An MTL700 700P Series barrier fitted with the DRK7OO can be attached to standard T section 35mm DIN rail alongside MTL7000 and MTL7700 Series products See Figure 19 6 1 14 Dummy barrier MTL799 This accessory allows for expansion when designing a system and is a convenient means of r
11. ve lead model descrip Basic circuit and then studs amp studs amp to term l to term no tion between ve Jead ve lead l amp dum j avs and 4 to to 1 lea lea then 2 then 2 term 2 term 2 TOpA 20mA 3 1 Min Max Min Max Min Max O 11V 51Q Ofi 590 630 co x1 10 0V 10 9V 10 14 J11 1V 791 co x2 41V 519 T E 592 630 M x1 oo 10 0V 10 9V 10 1V 11 1V O 94 O 4 2 INM700 10 June 2005 26 APPENDIX A ATEX certification information The Essential Health and Safety Requirements Annex Il of the EU Directive 94 9 EC the ATEX Directive safety of apparatus requires that the installation manual of all equipment used in hazardous areas shall contain certain information This annex is included to ensure that this requirement is met It compliments the information presented in this document and does not conflict with that information It is only rel evant to those locations where the ATEX directives are applicable General a In common with all other electrical apparatus installed in hazardous areas this apparatus must only be installed operated and main tained by competent cero Such personnel shall have under gone training which included instruction on the various types of protection and installation practices the relevant rules and regulations and on the general principles of area classi fication Appropriate refresher training shall be given on a regular bas
12. 009WT KDB Nr 91 010W KDB Nr 91 011W KDB Nr 91 012W Ex ia IIC Romania ISM STAS 6877 4 87 ISM Nr 90 2820 ISM Nr 90 2821 SM Nr 90 2822 ISM Nr 90 2820 Ex ia IIC Switzerland SEV EN 50 020 ASEV 84 14332X ASEV 84 14332X ASEV 84 14332X ASEV 84 14332X EEx ia IIC UK BASEEFA EN 50 020 Ex832452b Ex84B2307 Ex87B2428 Ex832452 EEx ia IIC UK BASEEFA Systems EN 50 039 Ex832469 Ex842308 Ex872513 Ex832469 EEx ia IIC UK BASEEFA BS 4683 Pt 3 Ex83453 Ex83453 Ex83453 Ex N II T6 in MT20N UK BASEEFA Indian vn EN 50 020 Ex89C2346 Ex89C2347 Ex89C2346 EEx ia IIC UK HSE MJ EN 50 020 HSE M 8570006 HSE M 8570006 EEx ia coal mining UK Lloyds Reg Type Approved 86 00102 86 00102 86 00102 86 00102 All vessels registered USA FM 3610 Entity J I TH8AT AX J I IKAAT AX J OR6AT AX J I 2P0A4 AX Class Il Ill Div 1 AG J l 2P0A4 AXc USA MSHA Classified 132011 17 20 31 40 44 132010 Mining systems USA UL UL 913 E120058 E120058 E120058 E120058 Class II Ill Div 1 AG CIS VNIIVE GOST 22782 5 78 N 144 N 144 N 144 N 144 Ex ia ib IIC EN 50 020 amp IEC 79 11 MTL758 certification in hand tincluding MTL787S Note UK BASEEFA is to CENELEC standards INM700 10 June 2005 MTL758 CE Ex222 92 approved for BR Ex ib IIC MIL791 Ex94C2172 c MTL791 J 1 4X0A4 AX approved additionally for non incendive Class 1 Div 2 ABCD Table 6 Approvals for MTL70OP Series high power barriers see begini
13. 1EC529 1P67 4 x 20mm holes pre drilled through Gland fixing top and bottom Top and bottom gland plates detachable for drilling by user Permitted location Non Non Non Non Non Zone 2 hazardous hazardous hazardous hazardous hazardous BASEEFA certificate Safe area Safe area Safe area Safe area Safe area No Ex83453 Certification Code Ex N II T6 BS 4683 Pt 3 1972 Mounting see figure 7 Corner screws or plastic lugs screwed to base Plastic lugs screwed to base Fixed mounting lugs plugged knockout holes or rearfixing screws Mounting kit provided 2 lugs attaching 4 lugs attaching As MT12 None screws screws 4 plugs but 6 off Tagging facility provided None Tagging strip s with label s and seal s Cable trunking provided No No No No Yes Yes Take care IS label provided Adhesive front inside lid Adhesive back on lid Earth terminals provided Large 1 mm 6AWG 0 3 3 3 3 3 Small lt 4mm 12AWG 3 3 6 12 16 10 Weight ex barriers kg 0 36 1 08 2 20 4 61 6 83 12 62 4 SAFETY CONDITIONS MTL recommends that on completion of any work on a barrier e installation each item on the checklist is again checked out preferably 4 1 General safety requirements by someone other than the person who actually carried out the work All users of shunt diode barriers should be familiar with the installation instructions given in a nationa
14. MTL706 consumes less current than the MTL702 and allows 2 way communication with most smart transmitters Note that when undertaking the MTL702 706 substitution terminals 3 and 4 of the MTL706 are reversed in polarity to those of the MTL702 The MTL707 can replace the MTL787 provided only that the small extra voltage drop can be accepted It accepts power supplies up to 35V without blowing its fuse The MTL708 can replace the MTL728 with the same provisos and advantage and also that the 1mA leakage current through the 708 s electronic protection network is acceptable The MTL787S can always replace the MTL787 and drops 1 5V less at 20mA Also under most circumstances it can replace the MTL788 for use with 2 wire 4 20mA transmitters Table 1 Key barriers summarised TYPE APPLICATION KEY BARRIER Analogue Resistance temperature detectors 755ac input low level Thermocouples ac sensors 760ac Analogue Controller outputs one line earthed 728 output Controller outputs neither line earthed 787S dc power supply 26 0V 20 35V Analogue Transmitters 2 wire 4 20mA 787S 706 input high level Digital on off Switches 7878 707 input Digital on off Solenoids alarms LEDs 728 708 output Table 2 Patents issued to MTL7OO and 700P Series barriers BARRIER UK PATENT USA PATENT MTL706 2205699 4967302 MTL707 2245439 and 2210521 MTL708 2210521 MTL7
15. apparatus and when mounted in an appropriate enclosure can be installed in the following areas a Non hazardous locations b Class 1 Division 2 Groups A B C and D hazardous locations c Class Il Division 2 Groups F and G hazardous locations d Class Ill Division 2 hazardous locations Barriers must be installed in enclosures meeting the requirements of ANSI ISA S82 Use Factory Mutual Research Corporation approved dusttight enclosures appropriate for environmental protection for the following locations a Class Il Division 2 Groups F and G hazardous locations b Class Ill Division 2 hazardous locations For installation guidance see ANSI ISA 12 6 and the National Electrical Code See also Installation drawing SCI 326 Notes 10 to 14 inclusive relate to table 15 Note 10 The non hazardous safe location equipment must not generate or use voltages in excess of 250V rms or dc Note 11 The hazardous location equipment Any number of FMRC approved devices which meet the power and entity parameter requirements below may be connected to the Fieldbus a All device s electronic circuitry which interface directly to the fieldbus must be powered from fieldbus power Other power sources in the devices if any must be galvanically isolated from the fieldbus power b Vmax of all devices must be equal to or greater than 22V c Imax of all devices must be equal to or greater than 233mA d Pmax of all devices must be equal to or grea
16. contains a source of potential with respect to earth that exceeds 250V rms or 250V de under normal or fault conditions unless specifically permitted by the safety documentation Note one phase of a 3 phase supply of up to 440V is permitted as that value is the equivalent of 250V rms Ensure that all barriers are adequately protected from moisture dust dirt vibration mechanical damage unauthorised modification and excessive temperature variations Ensure that all enclosures in which barriers are mounted are effectively sealed and that cable glands are correctly fitted 4 1 8 1 5 1 and 6 2 5 1 6 28 8 1 7 2 88 1 7 2 88 1 7 48 8 1 7 48 8 1 7 4 7 4 7 4 amp 8 1 7 3 7 4 5 1 amp 6 2 7 3 7 3 5 18 62 5 287 1 INM700 10 June 2005 8 5 2 2 Rear fixing not MT2 MT5 and MT20N Enclosures are mounted from the rear with this method using the M6 screws provided First drill holes through the surface onto which the enclosure is to be mounted positioned so as to align with the tapped holes at the rear of the enclosure These positions are the same as for corner screws in paragraph 5 2 1 and are shown in figure 6 Then using the M x 12 screws provided fix the enclosure into place from the rear It will be necessary to use longer M screws than those provided if the thickness of the material on which the enclosure is mounted exceeds about 6mm 5 2 3 Fixing lugs All models can be moun
17. current flowing in both directions Multimeter tests Constant current tests Barrier dat TET End to end Channel resistance Diode test isolation Voltages obtained when test test applying constant current between earth studs and Connect Connect terminal 1 and earth between between Connect studs and terminal 2 MTL Safety T terminals earth studs between both polarities model descrip Basic circuit land3 amp terminal 1 terminals 1 no tion gnd then and then ias etween termina 2 and 4 both polarities 10pA 20mA Min Max Min Max Min Max 760 10V 500 670 850 co co 6 0V 9 4V 6 9V 10 1V 765 15V 100Q 117Q 135Q co co 12 0V 14 0V 12 7V 14 7V 772 22V 3000 3170 3400 co co 18 0V 20 2V 19 4V 21 2V INM700 10 June 2005 25 Table 28 Tests for diode return barriers The table gives details for testing positive polarity barriers For negative polarity barriers the same values apply but the multimeter and supply leads must be reversed Multimeter tests Constant current tests Barrier data End to end Channel resistance Diode test isolation Voltages obtained when test test applying constant current between earth studs and Connect terminal 1 and earth Connect Connect Connect studs and terminal 2 MTL Safety ve to 1 ve to 1 ve lead to ve lead to between both polarities model descrip Basic circuit ve to 2 ve to 2 earth studs earth stud
18. drops in series it is worth noting that the full scale range of some multimeters is only 2V on the diode test range Therefore with three or more diode drops it is possible that the meter may indicate overrange and any voltage drop of more than 4V has been indicated in the test tables this section and section 11 as infinity Zener diodes and ordinary silicon diodes have a typical forward voltage drop of approximately 0 6V per diode Diode return paths with schottky diodes have a typical voltage drop of lt 0 3V for each diode in the chain e g MTL787S and 787SP Figure 35 shows a typical switch status transfer circuit protected by an MTL787S barrier which can be used to illustrate some of the fault finding techniques discussed in this section To determine the serviceability of barriers proceed as described in the remainder of this section but whenever possible always check barriers by working on the non hazardous safe area terminals and the circuits connected directly to them INM700 10 June 2005 9 1 Power supply check Check that the power supply is available to the barrier circuit and that the voltage across the supply and with respect to earth is correct For example referring to figure 35 the presence of 24V on terminal 1 and 12V on terminal 2 when the hazardous area switch is closed confirms the serviceability of almost the complete circuit Non hazardous safe area i 3400 i 3 Hazardous area 30
19. 0 1 38 1000 Table 18 Entity concept parameters for two channel MTL7OOP barriers with an optional ground return figure 31 and notes 6 to 9 Barrier Groups Voc Isc Ca La model No V mA pF mH MTL 707P C E 27 4 160 0 45 6 21 707P DEG 27 4 160 1 20 11 5 761Pac A B 18 0 50 0 43 14 4 761Pac C E 18 0 50 1 29 53 0 761Pac DEG 18 0 50 3 46 119 0 766Pac A B 23 0 297 0 22 0 20 766Pac CE 23 0 297 0 66 1 72 766Pac DEG 23 0 297 1 77 3 39 Note 1 The hazardous location mounted equipment may be switches or ther mocouples Other apparatus such as RTDs LEDs non inductive resistors and strain gauge load cells for the systems shown in fig ures 32 and 33 may be used if the auto ignition temperature of the hazardous location is greater than T4 275 F 135 C For the sys tems shown in figures 28 29 and 30 certified devices with the cor rect entity concept parameters can also be used The non hazardous location or control room mounted equipment should not use nor generate more than 250V rms For guidance on the installation see ANSI SA RP 12 6 Five MTL7OO Series barriers are approved for installation in Group F MTL705 707 708 787S and 758 All MTL7OOP Series barriers are approved for Group F Full details of all approved combinations are available on MTL drawing No SCI 88 Notes 6 to 9 inclusive relate to tables 16 to 19 inclusive Note 6 The barriers are associated
20. 2 channel positive and negative Zener diode barriers These barriers have similar properties to the 1 channel barriers detailed in table 22 The table gives details for testing positive barriers For negative polarity barriers the same values apply but the multimeter and supply leads must be reversed Multimeter tests Constant current tests Barrier data End to end Channel resistance Diode test isolation Voltage obtained when test test applying constant current Connect Connect Connect Connect to terminal 1 jon and between ve lead to ve lead to between t Pa termino d ve MTL Safety AS terminals earth studs earth studs term Is 1 amp 2 earth studs ve model description Basic circuit land3 amp ve lead amp ve lead both no and then to terminal to terminal polarities between 1 amp then 2 1 amp then 2 TOA 20mA 2 and 4 Min Max Min Max Min Max 758 7 5V 100 150 80 co gt xl co 6 0V 6 9V 6 5V 7 3V 764 12V 1KQ 1 0kQ 1 1kQ co gt x co 10 0Y 11 4V 10 4V 11 8V 767 15V 1000 1130 1550 co gt xl co 12 0Y 13 9V 12 4V 14 5V 768 22V 1500 1670 1850 co gt x2 co 19 0Y 20 7V 19 8V 21 1V 779 28V 300Q 3170 3400 co gt x2 co 25 5V 26 3V 26 1V 26 7V 26V 300Q 3170 3400 co gt x2 eo 23 5V 24 4V 24 1V 24 8V 796 20V 3900 4070 4350 co p x2 co 17 5V 18 8V 18 3V 19 2V 28V 3000 3170 3400 co gt x2 co 25 5V 26 4V 26 1V 26 8V 788 10V 50Q 670 850 co p x2 eo 6 0V 9 5V 6 6V 9 9V
21. 28V 3000 3170 3400 co p x2 co 25 5V 26 4V 26 1V 26 8V 788R 10V 50Q 670 850 0 33V 0 33V p x 2 0 33V OV OV 6 2V 6 8V INM700 10 June 2005 23 Table 24 Tests for 1 channel ac Zener diode barriers Owing to the symmetry of these barriers measurements should be made with the current flowing in both directions Multimeter tests Constant current Safety model descrip Basic circuit between between continuity terminals terminals 1 between tests Barrier t End to end gt arrier data resistance Diode test Voltages obtained when test applying constant current to terminal 1 and Connect Connect Check for MTL earth studs both polarities Table 25 Tests for 2 channel ac Zener diode barriers Owing to the symmetry of these barriers measurements should be made with the current flowing in both directions no tion 1 and3 amp 2 both term ls 2 8 4 polarities to earth studs 104 A 20mA Min Max Min Max Min Max 710 10v 500 670 850 co Y 6 0V 9 5V 6 9V 10 2V 728 28V 300Q 3170 3400 co Y 24 5V 26 5V 25 7V 27 5V Multimeter tests Constant current tests Barrier dat da End to end A Channel resistance Diode test isolation i test test Voltages obtained when applying nt current to termina an gonned panned Connect earth studs both polarities MTL Safety EROR terminals earth studs between model des
22. 5 12 0 13 0 100 15 100 150 55 12 0 13 0 100 768 22 150 147 y y 18V de systems 85 19 0 20 2 50 22 150 147 768 amp 779 require channels 85 19 0 20 2 50 779 28 300 93 v y Controller outputs sep rciesin IC 340 25 5 26 6 50 28 300 93 340 25 5 26 6 50 796 26 300 87 NN Vibration probes 340 23 5 24 6 50 20 390 51 MTL796 negative 435 17 5 187 50 760 10 50 200 y Active de 8 ac sensors 3 1 85 6 0 7 4 50 10 50 200 O Oo 85 6 0 7 4 50 765 15 100 150 y 135 12 0 13 2 50 15 100 150 de 135 12 0 13 2 50 772 22 300 73 y 2 wire de amp ac systems 340 18 0 19 7 50 22 300 73 S 340 18 0 197 50 778 28 600 47 y oO O 665 24 0 25 7 50 28 600 47 4 Star connected Note 7 2 665 24 0 25 7 50 786 28 diode Voy Signal returns 1 2 2V 30W 25 5 26 6 50 28 diode o 2 2V 30W 25 5 26 6 50 O 2 787 28 300 93 NN Controller outputs i 340 25 5 26 6 50 28 diode switches O 2 2V 30W 25 5 26 6 50 7875 28 300 93 y Transmitters 340 25 5 26 6 50 28 diode Controller outputs 0 9V 20W 25 5 26 6 50 switches O 2 788 28 300 93 y y 1 340 25 5 26 6 50 10 50 200 o 85 6 0 6 9 50 Transmitters 340 25 5 26 6 50 788R 28 300 93 y y 85 6 0 6 9 50 10 50 200 O 4 10y 2 791 11 51 216 y H1 31 25kbit s Fieldbus 3 1 62 6 10V at 50pA 10 5 100 11 51 216 y installations O 1 O 62 6 10V at 50pA 10 5 100 Internal terminator L O l O 4 2 R 3 1 799 Dummy barrier for securing cables for future installations o Terminal 182 O open circuit Fa i o 4 2 a Tolerance 0 15W a
23. 7208 28 300 93 MT7099 ale MT7299 zaf INM700 10 June 2005 Number of Maximum permissible 2 single channels cable parameters interconnected Earth BASEEFA group IIC hydrogen Matched within the return Capacitance Inductance L R ratio power Model no hazardous area used pF mH pH Q W MTL7106 7206 Yes 0 083 4 1 54 0 65 MTL7207 2 Yes 0 083 4 1 54 0 65 MTL7208 Yes 0 083 4 1 54 0 65 MTL7122 Yes 0 165 1 66 44 0 81 MTL7028 7128 Yes 0 083 4 1 54 0 65 MTL7128P Yes 0 042 1 26 42 0 83 MTL7028 7128 Yes 0 083 4 1 54 0 65 MTL7129P Yes 1 19 MTL7055ac Yes 1000 0 4 158 0 23 2 Yes 1000 0 1 79 0 45 2 No 40 0 4 79 0 45 3 No 40 0 22 59 0 68 4 Yes 40 0 035 31 25 0 92 MTL7056ac Yes 1000 0 4 158 0 23 3 No 40 0 22 59 0 68 MTL7060ac 7160ac Yes 4 9 2 47 131 0 27 2 Yes 4 9 0 61 65 0 54 MTL7061Pac 7161Pac 2 No 0 309 54 2 307 0 12 MTL7261ac Yes 4 9 3 55 158 0 23 2 Yes 4 9 0 88 79 0 45 MTL7162 Yes 3 0 0 89 71 0 50 2 Yes 3 0 0 22 35 1 0 2 No 1 97 2 93 117 MTL7164 Yes 1 41 246 987 0 04 2 Yes 1 41 61 7 493 0 08 MTL7264ac Yes 1 41 246 987 0 04 2 Yes 1 41 61 7 493 0 08 No 0 125 246 493 0 08 MTL7265ac Yes 0 58 1 58 63 0 56 2 Yes 0 58 0 4 31 1 13 MTL7066Pac 7166Pac 2 Yes 1 41 0 36 37 0 96 MTL7167 Yes 0 58 1 58 63 0 56 2 Yes 0 58 0 4 31 1 13 MTL7278ac Yes 0 083 16 1 108 0 33 2 Yes 0 083 4 02 54 0 66 MTL7087 7187 2 Yes 0 083 4 1 54 0 65 MTL7087P 7187P 2 Yes 0 042 1 26 42 0 84 MTL7096 7196 2 Yes 0 134 1 86 44 0
24. 764 13 25 6 1 800 12 05 12 1 5 200 764ac 24 10 12 0 18 200 12 05 12 1 5 200 765 15 08 75 4 0 70 6 15 08 147 0 7 13 766 24 10 80 4 0 18 5 6 12 05 80 1 5 5 6 767 16 35 75 8 0 50 6 15 15 147 0 7 1 7 768 23 33 73 5 0 20 6 22 13 147 0 2 1 7 772 22 13 36 9 0 20 22 22 13 73 0 2 6 778 28 23 23 6 0 12 58 28 23 46 0 12 14 779 29 37 46 5 0 11 14 28 17 93 0 12 4 786 29 20 0 0 11 500 28 00 0 0 12 500 787 28V ch 29 74 94 0 10 4 28 54 94 0 11 4 787 diode ch 28 00 0 0 12 500 788 788R 28V ch 28 75 82 0 11 5 6 28 15 93 0 12 4 788 788R 10V ch 10 04 189 3 0 1 796 26V ch 27 30 40 0 13 22 26 10 86 0 14 4 7 796 20V ch 20 05 51 4 0 3 13 Parameters when barrier channels are interconnected Class II lass Il equipment Hazardous location Class Div 1 Groups A B C D Div 1 Groups E G Hazardous location Non hazardous safe location 2 channel barriers no ground return see note 1 on page 20 Ground 12 max F 2 channel barrier Non hazardous safe location devices V lt 250V max see note 2 on page 20 Note No ground return permitted nor grounded shields or conduit Figure 29 2 channel barrier connection with no ground return Hazardous location Class Div 1 Groups A B C D Class Il Div 1 Groups E G lass Il Non hazardous safe location Each chan nel with ground return Hazardous location equipmen
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27. 87S 2210522 4860151 MTL707P 2210521 4860151 and 2210522 MTL787SP 2210522 4860151 3 2 General specifications 3 2 1 Terminology Notes 1 to 7 in tables 3 and 4 1 Safety description The description of a barrier eg 28V 300Q 93mA refers to the maximum voltage of the terminating Zener or forward diode while the fuse is blowing the minimum value of the terminating resistor and the corresponding maximum short circuit current It is an indication of the fault energy that can be developed in the hazardous area not the working voltage or end to end resistance 2 Polarity Barriers are polarised positive negative or non polarised ac Polarised barriers accept and or deliver non hazardous safe area voltages of the specified polarity only Non polarised barriers support voltages of either polarity applied at either end 3 End to end resistance This is the resistance between the two ends of a barrier channel at 20 C ie of the resistors and the fuse If series diodes or transistors are present their voltage drop transistors ON is quoted in addition 4 Working voltage Vwkg This is the greatest steady voltage of appropriate polarity that can be applied between the non haz ardous safe area terminal of a basic barrier channel and earth at 20 C for the specified leakage current with the hazardous area terminal open circuit INM700 10 June 2005 5 Maximum voltage Vmax This is the greates
28. MTL700 and 700P Series shunt diode safety barriers INM700 Contents 1 INTRODUCTION celere o o o s s snl 2 DESCRIPTION vipimo ey ei yh numo m ro ei a i sis P os ms ese 3 BARRIER SPECIFICATIONS oooooooooooooooooooosnoosrrosroosnoosnosso I 3 1 The MILZO0 and 700P Series ans eatin dead a Sauk uu o EG RED ae dis Hilde MS Ge RE 1 3 2 General specifications lek 589 dep kebes rd S RPM IE SERE RIS 2 3 3 Additional specifications ds soe ces eR Ra atone aoe CRX RR UP esee oie BE eden eek EE E GV d e eb E RR 2 34 Comrmion specilicallon c hdd AR A ee E LS SZ LA eee 3 3 5 JAppt vals 2 deta Pee e nv bec bee Ves itd d S Eoo da bala Serie Sos 5 3 6 Enclosure specilications xus ud e eo ca ote a OUR AURI PARS OIN PR eden ieri e QUIE Gv qe ehe ON RR 6 4 SAFETY CONDITIONS ooooooooooooooooooonoonosonosoroosoo o 4 1 4 2 General satety requirements 2 A A AA e RR Rede da A ita 6 Salely checks netiria nr rs te ibe bye Ped ti REO te ee PES wes 6 5 MOUNTING THE BARRIERS 0 ccc cece hh hn ENCLOSED SYSTEMS io genes dre dudes des ld atone aoe 5 1 5 2 Fitting the barriers into the enclosure 26 liie s 7 Mounting thezenclosure ji Gccy tr eee ae acd pe Ae ty ges is 7 6 MOUNTING THE BARRIERS UNENCLOSED SYSTEMS ooooooooo B n n n ng n S 6 1 The MTL7OO and 700P Series accessories range iis 9 6 2 Constructing the installation s a csse eee eee
29. a small number of barriers the earth connections will have to be made directly to the barriers earth studs Figure 26 shows a recommended method where the two earths are connected to different barriers with the remaining studs all linked together The earth conductors must have a minimum cross sectional area of 4mm2 Hazardous area cable screens can be connected to the earth studs or terminal 3 and 4 of an MTL799 dummy barrier b S LO le F dsl Amm terminals for earthing hazardous sa NS area screens or earth des relums Ro 16mm terminals for ne uplicated earth m Mrd connections qo ale O Y 16mm terminal for safe area OV connections or power supply returns Figure 24 Usage of earthing terminals Local 3 distribution Q7 transformet Resistance meter or bonding integrity Loop monitor lt resistance lt 20 Figure 25 Earthing with two conductors 7 3 Connecting non hazardous safe area cables to barriers The non hazardous safe area cables must be connected only to terminals 1 and 2 of MTL700 700P Series barriers They should be segregated from hazardous area cables and routed from the non hazardous safe area equipment via the non hazardous safe area loom conduit or trunking Care must be taken if standa
30. acitance Inductance L R ratio Capacitance Inductance BASEEFA hazardous area pF mH en pH Q pF mH 1 2 39 47 IN N e Ico lov Ne ey rg ry ooo aN JO O Olla a gt Alo in MU Rlo Bla Ria Rolo lolo lo hwo no INSU Ito ze N Ip pp A BR Nip po lou ESESERERE LOCOCO IND On oo a afo o ESCESEE e oNS lop iom lO A eoo o SEP lo 0 9 lolo 0000 a plow ISH IS NN a Un lia o Ze o BS ho IS lg SOL asks 77 2ac 6 77 1 45 778ac 16 3 05 779 3 05 786 787 amp 7875S 3 05 Z87SP 1 82 788 amp 788R 0 33 791 0 30 796 1 94 BASEEFA group IIB Z07P 5 65 729P 5 65 o olo Soba R bolalo pp Ao OJula N IN Io OOOO P Slo ojojo ol lo ko bo IN OP INI la a o DO P P O ho BASEEFA BASEEFA 1 iam PRA Farh Maximum permissible cable parameters for group IIC hydrogen power Cert No used Capacitance pF Inductance mH or L R ratio pH Q BASEEFA 1x715P Ex92C2425 Yes 0 135 0 23 39 3 0 91 Ax764ac 2 x 761ac channels 2 x 764ac channels 2 x 766ac channels 4 x 761ac channels Ex842125 Yes 0 2 0 2 12 7 0 98 s s s Ex842125 Yes 0 2 0 24 11 6 1 01 2 x 764ac channel Ax761Pac channel 2x766Pac channel Ex92C2424 Yes 0 18 0 17 18 4 1 17 2 x 764ac channels Ex842128 0 2 0 28 11 1 04 4 x 766ac ch
31. age 20 It 233mA Po 1 18W F Ground 10 max Figure 34 Fieldbus barrier system using MTL791 barrier and FBT1 terminator 7 8 Entity concept parameters for MTL7OOP Series FM Table 16 Entity concept parameters for single channel MTL7OOP barriers with ground return see figure 28 and notes 6 to 9 Barrier Groups Voc Isc Ca La model No V mA pF mH MTL 710P A B 9 0 267 4 89 0 22 710P C E 9 0 267 14 6 2 23 710P D F G 9 0 267 39 1 4 22 715P A B 13 7 264 1 04 0 23 715P CIE 13 7 264 3 13 2 27 715P D F G 13 7 264 8 37 4 30 722P A B 20 1 194 0 33 0 53 722P CE 20 1 194 0 99 4 33 722P D F G 20 1 194 2 65 7 96 728P A B 26 3 112 0 16 2 86 728 G E 26 3 112 0 49 12 0 728P D F G 26 3 112 1 32 23 8 729P CLE 26 3 160 0 49 6 25 729P D F G 26 3 160 1 32 11 6 INM700 10 June 2005 18 Table 17 Entity concept parameters for 2 channel MTL787SP barriers with diode return figures 29 30 and 31 and notes 6 to 9 Figure 29 Figure 30 Figure 31 Model No Groups Voc Isc Ca La Voc Isc Ca La Voc Isc Ca La MTL v ma pF mH v mA pF mH V mA pF mH 787SP A B 28 9 115 0 13 2 70 25 9 110 0 17 2 93 28 9 115 0 13 2 70 28V ch CE 28 9 115 0 39 11 52 25 9 110 0 51 12 3 28 9 115 0 39 11 52 DEG 28 9 115 1 06 22 57 25 9 110 1 38 24 3 28 9 115 1 06 22 57 787SP A B 25 9 0 0 17 1000 diode ch CE 25 9 0 0 51 1000 DEG 25 9
32. angement will also allow DIN rail item 1 Mounting centres hole diameters MK5 140 4 5 nom MK12 200 and 5 5 nom 179 choice MK20 357 5 5 nom All dimensions in mm Figure 23 MK5 MK12 and MK20 kit assembly diagram Note MK5 has no items 4 and 10 See 6 5 4 d INM700 10 June 2005 the circuit to be monitored continuously by a bonding integrity monitor such as the MTL2316 which gives warning if there is a significant increase in resistance or if large currents are sensed IS earth conductors should be identified by coloured insulating tape preferably blue wound around them at intervals along their length It is common practice but not mandatory to insulate IS earth busbars and associated conductors from the surrounding metalwork and plant earth cables This minimises the possibility of the earth circuit being invaded by leakage or fault currents which through common impedances might interact adversely with this and other systems It is far easier to design an insulated installation than to discover later that insulation is necessary when disassembly and power removal will be unavoidable MTL700 700P Series accessories IMB7 and SMB7 insulating mounting blocks are a convenient method of insulating busbars as shown in figure 20 Further information about the earthing of IS systems is contained in BS 5345 Part 4 1977 Section 3 Code 16 If SCM7 surface mounting clips are used to mount
33. annels 758 76lac Ex872392 0 42 0 013 10 5 BASEEFA Maximum permissible cable parameters for group IIB not safe for group IIC 4 x 764ac channel Ex842128 0 6 1 1 32 6 4 x 766ac channe 2 x 768 channels Ex842114 0 78 1 8 70 2 x 768 channels Ex842114 0 39 1 8 46 6 Any number of 786 channels 2 x 9 channels Ex842114 2 x 779 channels Ex842114 Any number of 786 channels L R 31pH Q The tables give the maximum permitted cable parameters including cable and load for hazardous area circuits in group IIC and IIB gases However the tables are by no means exhaustive and for full details of other safe combinations consult either BASEEFA system certificates Ex832469 Ex92C2374 or Ex92C2376 or MTL The MTL702 is covered by BASEEFA system certificate Ex842308 and the MTL706 by Ex872513 In practice cable parameters rarely present a problem as all cables normally used for instrument interconnection have L R ratios below 25pH Q and capacitance below 200pF per metre Note 1 If a No value is not quoted for a barrier use the Yes value Note 2 The maximum power that can be drawn from the barrier combination under fault conditions Used for assessing the temperature classification of simple hazardous area apparatus Note 3 Values for Groups IIA and IIB are given on certificates BASO1ATEX7202 and BASO1ATEX7203 For FM permitted combinations refer to MTL document SCI 88 via FM ref 1H8A1 AX
34. any direct interconnection between hazardous and non hazardous safe area circuits The instructions given in section 4 of this manual should be observed at all times 8 1 1 Barriers should be of the types and polarities specified in the safety documentation 8 1 2 The barriers should be attached securely to the earth busbar thus making a good connection to the IS earth Use a TQS7 torque spanner or other suitable wrench to check that each barrier s two Nyloc nuts are tightened to a torque of 2 3Nm 20 lb in 8 1 3 There should be no signs of damage or corrosion to the bar riers or the IS earthing system 8 1 4 All connections should be properly made and the tightness of the hazardous and non hazardous safe area terminals on the barriers checked 8 1 5 Interconnecting cables should be of the type and rating spec ified in the safety documentation and not frayed or other wise damaged 8 1 6 All earth returns and cable screens from the hazardous area should be connected to earth via an earth rail and terminals 8 1 7 Visually examine the earth conductors and ensure that they are not damaged in any way and that their terminations are secure and free from corrosion 8 1 8 Using a low voltage low current test meter i e a meter whose output does not exceed 3V and 50mA measure the resistance between the earth busbar and the neutral star point of the supply and ensure that it does not exceed 1W Record the reading A consiste
35. arate insulated conductor and the structural earths of the barrier enclosure and safe area equipment returned separately to the neutral star point This technique reduces interference problems but is not essential for safety In general the use of barriers in all measurement leads reduces the possibility of earth circulating currents creating measurement problems Neutral star point earth Resistance to terrestrial earth is determined by other regulations It is NOT modified or determined by the intrinsic safety Zone O 1 or 2 Zone 2 or safe area Non hazardous safe area Figure 27 Bonding practice where hazardous area equipment cannot meet required standards of insulation from earth Enclosure Local distribution Barriers transformer Non hazardous safe area equipment Hazardous area equipment incapable of withstanding insulation test OV Bonding conductor XK DO nv Less than 100 metres 4mm min CSA 100 200 metres max 8mm min CSA requirements INM700 10 June 2005 7 5 Cable parameters for MTL700 Series BASEEFA ATEX amp FM Table 9 Maximum cable parameters gas group IIC for notes 1 2 and 3 see bottom of page Barrier Number of Earth 1 Maximum permissible cable parameters Matched 2 model single channels return BASEEFA ATEX group IIC FM groups A amp B power number interconnected used w MTL within Cap
36. bonding conductor not less than 8mm2 cross sectional area CSA With this size conductor the bonding conduc tor must not exceed 200m in length If the bonding conductor is less than 100m the conductor need only be 4mm in cross sec tional area Where bonding conductors are used care should be taken to avoid invasion of other intrinsically safe systems which do not utilise bonding conductors by elevation caused by any currents which may flow in the common earthing systems due to the presence of the bonding conductor Where this possibility cannot be avoided then the busbar on which the barriers are fitted should contain only barriers associated with bonded systems and it should be earthed separately from other barrier busbars The hazardous area equipment and or adjacent metallic structure bond connections must be secure against vibration and corro sion A terminal of the type used on Type e equipment is the required solution The barrier busbar connections must provide adequate termination facilities for the bonding conductor and usual earth return by the provision of separate Type e terminals Where the barriers are located in Zone 2 the enclosure and the wiring to the non hazardous safe area connections of the bar rier must comply with the requirements of Type N protection Operational requirements This sketch shows the OV rail of the non hazardous safe area equipment returned to the barrier busbar by a sep
37. crip Basic circuit land3 amp terminal 1 terminals 1 no tion bes then ond then Baines etween termina 2 and 4 both polarities 10A 20mA Min Max Min Max Min Max 761 9V 900 102Q 1450 co co 6 0V 8 5V 6 9V 9 5V 761P 9V 3500 3670 3840 co co 7 OV 8 7V 7 1V 9 0V 764 12V 1 0kQ 1 0kQ 1 1kQ co co 10 0V 11 4V 10 7V 12 1V 766 12V 150Q 165Q 1850 co co 10 0V 11 4V 10 7V 12 1V 766P 12V 750 850 930 co co 9 8V 11 1V 9 9V 11 4V INM700 10 June 2005 24 Table 26 Tests for forward diode barriers These barriers use forward connected diodes as voltage limiters They are used for ac signals Multimeter tests Constant current tests Barrier data Eadec ond Channel resistance Diode test isolation Voltages obtained when test test applying constant current between earth studs and Connect Connect terminal 1 and earth between between Connect studs and terminal 2 MTL Safety HRS terminals earth studs between both polarities model descrip Basic circuit land3 amp terminal 1 terminals 1 no tion gnd then and then ook pom etween termina armies 2and4 both polarities 10A 20mA Min Max Min Max Min Max 751 1V 100 149 200 5 x1 gt x2 0 3V 0 6V 0 6V 1 0V 755 3V 100 17Q 190 P x3 B x 0 9V 1 8V 1 8V 2 8V Table 27 Tests for star connected ac Zener diode barriers Like positive and negative barriers these barriers are symmetrical and should therefore be tested with the
38. ctor should not exceed 1Q although in order to increase safety and minimise interference a resistance of 0 1W should be aimed for whenever possible The cross sectional area of the conductor must be greater than 4mm 12AWG Earthing the barriers Where the barriers are mounted on a busbar the conductor should be connected to the 16mm terminal on the ERB7 earth rail mounting bracket Alternatively the connection can be made directly to the busbar using a vibration proof ring tag For greater integrity a duplicate earth connection should be made to the terminal on a second ERB7 bracket On MT Series enclosures the earth connections should be made to the ERB7 brackets as described above or to the 4mm terminals in the case of the MT2 and fed into the enclosure via the non hazardous safe area cable gland Although terminals 2 and 4 on 1 channel barriers are internally connected to the barrier earth studs MTL702 705 and 706 terminal 4 only they SHOULD NOT be used as a means of connecting the system to the high integrity earth circuit To avoid the difficulty posed by the need to test the earth circuit periodically in accordance with the requirements of BS 5345 it is advisable to use two earth conductors for earthing the system as shown in figure 25 It is then possible to connect a multimeter into the loop to measure the loop resistance without disturbing the circuit In this case the resistance should not exceed 2Q This arr
39. d humidity limits 20 C to 60 C continuous working 40 C to 80 C storage 5 to 9576 RH Leakage current For basic barriers with a working voltage of 5V or more the leakage current decreases by at least one decade volt reduction in applied voltage below the working voltage over two decades For the MTL755 it decreases by at least one decade for a 0 4V reduction in applied voltage Terminations Terminals accommodate conductors up to 4mm 12AWG Hazardous area terminals are identified by blue labels Colour coding barrier top Grey Non polarised Red Positive polarity and MTL791 Black Negative polarity Black red label for safe area terminals positive supply negative to transmitter MTL706 White Dummy barrier MTL799 Weight 125g approximately Mounting and earthing By two integral M4 x 9 tin lead plated steel fixing studs and stainless steel self locking nuts provided 3 3 3 MTL707 707P additional specification Supply voltage Vs 10 to 35V dc positive w r t earth Output current lout Up to 35mA available Maximum voltage drop at 20 C current not limited MTL707 out X 3700 1 5V terminals 1 to 3 ou X 50Q 2 1V terminals 4 to 2 MTL707P out X 200Q 0 2V terminals 1 to 3 ou X 180 1 3V terminals 4 to 2 Supply current MTL707 ou IMA max Vs 26V Limited at 50mA Vs gt 28V or low load resistance MTL707P ou 2mA max Vs 25V Limited at 50mA Vs gt 28V or low load resistance
40. diode the expected reading across the diode chain can be determined Table 22 Tests for 1 channel positive and negative Zener diode barriers For negative polarity barriers the same values apply but the multimeter polarity and test leads must be reversed Barrier data Multimeter tests Constant current tests End to end inui resistance Diode test Continu ity Voltages obtained when test applying constant current to terminal 1 ve and Connect Connect Connect Check for earth studs ve MTL Safety EE between ve lead to ve lead to continuity model descrip Basic circuit terminals terminal 1 terminal 1 between no tion land3 amp ve lead amp ve lead term ls 2 amp 4 to term 2 to term 2 to earth studs 10pA 20mA Min Max Min Max Min Max 710 10V 50Q 670 852 co B x Y 6 0V 9 6V 6 6V 10 0V 710P 10V 33Q 380 420 co Be x Y 8 0V 9 0V 8 2V 9 5V 715 15V 100Q 1130 1550 co B xl Y 12 0V 14 2V 12 4V 14 9V 715P 15V 50Q T 560 600 co B xl Y 12 5V 13 4V 12 7V 3 9V 722 22V 150Q 167Q 1850 co Mm x2 Y 19 0V 20 9V 19 8V 21 3V 722P 22V 101Q 1120 1210 co gt x2 P4 18 5V 20 0V 18 6V 20 3V 728 28V 3000 3170 3400 co gt x2 Y 25 5V 26 5V 26 1V 26 9V 728P 28V 2340 2400 2530 co e x3 Y 24 5V 25 7V 24 7V 26 0V 729P 28V 1640 1730 1840 co p x3 24 5V 25 7V 24 7V 26 0V Voltages obtained when applying a 40mA constant current Table 23 Tests for
41. dous Locations 7 9 Final check After completing the installation each item contained in the checklist table 8 should again be checked out by a competent person preferably someone who has not been involved in the work 8 MAINTENANCE Since the MTL700 700P Series barriers are encapsulated they cannot be repaired but provided they are connected correctly to the circuits they are intended to protect and provided those circuits are not themselves defective barrier defects are unlikely to occur For these reasons servicing of barrier installations consists principally of the routine inspection and earth testing described in this section If replacements do have to be fitted however it is worth checking in the case of barriers connected directly to power supplies if one of the new overvolt protected models can be substituted These models can tolerate supply voltages up to 35V de without blowing their fuses and can therefore eliminate the problem of poorly regulated supplies Further information about the maintenance of barrier installations is given in BS 5345 Part 4 1977 Section 4 8 1 At intervals of not more than two years more frequently for particular environments visually check the barrier installation to check the following points Routine inspection When undertaking these checks personnel should comply with all the regulations relating to the safety of the plant and personnel Great care must be taken to prevent
42. e hazardous area are certified compatible with the barrier combination being used Then check that the cables used for connecting the barriers to the hazardous area equipment conform with the type of cables specified in the safety documentation Make sure that the maximum permitted cable parameters stipulated for the particular types of barrier in tables 9 to 12 BASEEFA or tables 13 to 22 FM are not exceeded In general cable parameters are unlikely to present problems except where cables longer that 500m are used for Group IIC applications Hazardous area equipment and its interconnections should be isolated from earth to the extent that it is capable of withstanding a 500V isolation test but such tests can only be undertaken when the area is gas free Fortunately however most circuits may be tested at low voltages by first disconnecting at the barrier any cable connected directly to earth or returned via a barrier with a nominal voltage of less than 10V The resistance to earth of the non hazardous safe area terminals can then be checked with a multimeter and should be greater than 100kQ Note some hazardous area instrumentation e g pH and conductivity is by its nature unable to withstand the 500V insulation test method mentioned above Where this is the case the system may alternatively comply with the installation requirements specified in IS sketch 121 figure 27 and BS 5345 Part 4 1977 Section 3 Code 16 Hazardous area
43. e spanner or a torque wrench set to 2 3Nm 20 Ib in Note that damage to the threads may occur if a higher torque than this is applied Ensure all the barriers hazardous area terminals face the haz ardous area side Where barriers are mounted in rows on par allel busbars the barriers in alternate rows should be reversed to keep the hazardous and non hazardous safe area termi nals apart Also ensure that there is sufficient clearance to allow their removal and replacement as shown in figure 21 Slide the required number of ETM7 earth terminals onto the ERL7 earth rail and fit this assembly into the large terminals on the ERB7 brackets Tighten these large terminals using a 10mm A F spanner Complete the installation by fitting the tagging facilities First take the 1 metre length of TAG7 tagging strip and remove the pack of four clic rivets taped to the underside Also remove the clic rivets from both ends of the strip by pressing them out from the rear The TGL7 tagging strip label can now be removed and along with the TAG7 tagging strip cut to length if necessary After the TGL7 tagging strip label has been marked with loop identification numbers etc refit it into the TAG7 tagging strip and secure it by replacing one of the clic riv ets If the TAG7 has been cut to length drill a 3 2mm diameter hole in the cut end diagonally opposite the existing clic rivet 7 5mm along 12 5mm in to accommodate the tagging seal C
44. earth returns and cable screens should be earthed via the ETM7 earth terminals mounted on the ERL7 earth rail on the mounting bracket in the case of the MT2 enclosure However in the case of 1 channel barriers earth returns and cable screens can be connected to terminal 4 of the barrier with which they are associated because that terminal is internally connected to the earth studs All unused hazardous area cables should be secured safely to terminals 3 and 4 of an MTL799 dummy barrier or by some other suitable method Figure 26 shows the MTL799 used as a convenient technique for terminating screens and is another possible use Earthy terminals of dummy barrier used to terminate screens Spare cores terminated in dummy barier MTL799 Wires to be 4mm cross sectional area CSA minimum ed Px Figure 26 Use of the MTL799 dummy barrier also shows alternative mounting method using SMC7 clips Where the hazardous area equipment is connected to earth either directly or indirectly and or it will not withstand a 500V insulation test to ground e g strain gauge bridges with low voltage insulation pH and conductivity measuring electrodes bare and or earthed thermocouples some level detecting elements the following apply 1 1 1 2 2 Safety requirements The pipe vessel or body of the hazardous area apparatus and or the adjacent metallic structure must be connected to the barri er busbar by a
45. ed by disconnecting the compensating cables from the thermocouple shorting them together and then measuring the temperature of the shorting point 10 2 Resistance thermometer detector circuit testing Hazardous area Non hazardous safe area Non hazardous MTL755 safe area equipment Bridge supply ES rz a 90 a ii D m Measurement Hd oOo Measurement x TX ES UY ty i 1 Li Variable 4 resistance i sic High integrity earth i resistance Figure 37 Calibrating an RTD barrier circuit Resistance thermometer detector RTD circuits can be tested by disconnecting the measuring leads from the RTD head in the hazardous area and connecting them to a resistance box Sometimes it is more convenient to connect the resistance box in the non hazardous safe area for instance at point xx as shown in figure 37 However in this case the RTD must be shorted out or allowance must be made for its temperature The effect of a negative temperature change can be simulated by connecting the resistance box in the measurement lead at point yy The advantage of connecting the resistance box at the RTD head is that any leakage can also be determined by connecting the resistance box at point yy 11 BARRIER TESTS Note There is no requirement for barriers to be subjected to routine testing if they are in normal use The tests given in this section have been included to enable
46. eee 10 6 3 Using SMC7 surface mounting clips eee teens 12 6 4 MK2 mounting kils costes a Pb UIN UAI Me METER E dd enia Nerd 12 6 5 MK5 MK12 and MK20 mounting kits seem e 12 7 WIRING INSTALLATION ccc ec cere cere B o rs sss nns s 13 7 Glanding cables into enclosures lee a 13 7 2 Earthing the barriers ye usus ose td xc od Bee Mh had a Be AE Sk ay Gi Re eee ae OE REE gis da nues 13 7 3 Connecting non hazardous safe area cables to barriers 14 7 4 Connecting hazardous area cables to barriers 5 14 7 5 Cable parameters for MTL700 Series BASEEFA ATEX amp FM I uen 16 7 6 Entity concept parameters for MTL70O Series FM ooo 17 7 8 Entity concept parameters for MTL7OOP Series FM sisse tenet tenes 18 7 9 hinalicheck 208 Tubes edu bo SEE UPS RIA Ib e bled e RU ee bet bed sees 19 8 MAINTENANCE 5 a yy enie ro eh vuoi uu e diro e is M 8 1 Routine inspection vivir a ike fs E RT Wee vERCCEEW Rd dL EN DEEP 19 9 FAULT FINDING cece cece crc hh s sss nn n ns n 20 921 gt Power supply check nri wr 2209 ee Esas Oves dd a Ele rete t tls 20 9 2 Barrier resistance test not MTL702 705 706 707 707P and 708 1 ee 20 9 3 Earilifaulis 5i dco sede a EU Cer PP woe re RNDUE eos PER CULA Pd 20 9 4 Faults between barrier channels aistien riaa rss 21 10 THERMOCOUPLE AND RTD TESTS oooooooooooooooooooooooooooooo 21 10 1 Thermocouple circuit testing o
47. en in sections 3 2 to 3 5 In 1992 3 a range of MTL7OOP higher power barriers was introduced and is listed under 3 2 General specifications The MTL7OOP Series barriers complement similarly numbered MTL7OO Series barriers but deliver more power into hazardous areas The series covers two distinct types one type is designed for IIC gas group areas while the other is for IIB gas groups The additional power available with the IIC units is made possible by a change in the BSI s interpretation of the requirements of EN 50020 which brings it into line with other European authorities It also corresponds with the requirements of North American standards The MTL7OOP barriers are mechanically identical to the MTL7OO Series barriers and are therefore compatible with all MTL7OO Series accessories Seven key MTL7OO Series models are highlighted in the sales literature as meeting most process control requirements These models and their applications are listed in table 1 The literature also cross refers to MTL7OOP Series barriers where a higher power barrier application may be required To minimise spares stocks and simplify maintenance procedures it is worth noting that the key barriers can often be used in place of other models the MTL706 can replace the MTL702 provided that the transmitter is certified for a Umax in of at least 28V and the transmitter and its lines require no more than 15V to operate Both are nearly always the case The
48. eserving a position or terminating spare leads and screens It is packed as a standard MTL700 700P Series barrier with hazardous area terminals 3 amp 4 internally connected to the fixing studs Non hazardous safe area terminals 1 amp 2 are not connected See figure 26 pagel 4 6 1 15 Mounting kits Four mounting kits are available the MK2 2 barriers MK5 5 barriers MK12 12 barriers and MK20 20 barriers Each kit provides facilities for mounting and earthing the barriers connecting the IS earth cable terminating earth screens and noting tagging information except the MK2 kit Assembly instructions are given in sections 6 4 and 6 5 See figures 22 and 23 pages 12 and 13 6 2 Constructing the installation Installing MTL700 700P Series barriers is very simple The barriers mount on standard earth busbar which is supported by insulating mounting blocks themselves mounting on any flat surface or suitable DIN rail In addition an earth rail plus terminals is provided for terminating cable screens and a tagging strip allows the barrier and its location to be identified Figure 20 shows how the accessories fit together to make up the installation and should be referred to while carrying out the construction procedure 6 2 1 Determine the number of barriers to be mounted on the busbar The maximum number is 25 between mountings but a 1 metre length of busbar can accommodate up to 64 barriers So for up to 25 barrier
49. han 0 9V should be expected Then connect between terminal 2 ve and 4 ve for a reading of x for the reverse voltage drop 9 2 5 Tests 9 2 3 and 9 2 4 confirm the continuity of both channels of the barrier If either channel is openccircuit it is most like ly that the fuse has blown in which case the non hazardous safe area circuit should be investigated If this is not the case and the fault has not been found then carry out the tests in sections 9 3 and 9 4 and if a fault is still not found remove the barrier for bench testing as follows 9 2 6 Remove the suspect barrier from the equipment and take it to a suitable area where it can be tested in accordance with section 11 Barrier tests If the barrier is found to be defec tive fit a new one of the appropriate model number Caution After the removal of the barrier ensure the safe area and hazardous area cables disconnected under 9 2 1 and 9 2 2 are either connected to an MTL799 dummy barrier or insulated completely 9 3 Earth faults Most intrinsically safe circuits are isolated from earth in the hazardous area If it is suspected that a system earth fault exists proceed as follows 9 3 1 Disconnect the hazardous and non hazardous safe area cables from the barrier terminals and either temporarily insu late them or secure them safely to the appropriate terminals of an MTL799 dummy barrier 9 3 2 For the barrier shown in figure 35 the readings shown in table 20 s
50. hould be obtained when connecting a test meter with the diode test function selected 9 3 3 In the case of the circuit shown in figure 35 with the haz ardous area cables connected to the terminals and the test meter connected between terminals 1 ve and 2 ve a read ing of x will be obtained if the switch is open and a reading of approximately 1 2V if the switch is closed and no earth faults are present To check if either of the hazardous area cables is shorted to earth connect the test meter as in table 21 which shows the readings that will indicate a fault to earth Table 20 Barrier earth fault tests with hazardous and non hazardous safe area cables disconnected Positive lead Negative lead Test meter on terminal on terminal reading 1 Earth studs oo Earth studs 1 1 2V 2 Earth studs oo Earth studs 2 1 2V l 2 oo 2 1 oo Table 21 Barrier earth fault tests with hazardous and non hazardous safe area cables connected Positive lead Negative lead Test meter Cable fault on terminal on terminal reading from terminal 1 Earth studs OV 3 to earth Earth studs 2 0 9V 4 to earth 9 4 Faults between barrier channels If it is suspected that faults exist between the channels of a 2 channel barrier proceed as follows Note that these tests are not applicable to MTL751 or 755 barriers 9 4 1 Disconnect the hazardous and non hazardous safe area cables from the barrier terminals a
51. ion MTL761 ac Hazardous location equipment see note 1 on page 20 MTL761 ac pipare F Ground 10 max Figure 32 Strain gauge bridge combination using MTL761 764 barriers Non hazardous safe location devices V lt 250V max see note 2 on page 20 Table 14 Entity concept parameters for strain gauge bridge systems using MTL761 764 766 barriers figure 33 Group Ca La pF mH A amp B 0 2 0 2 C 0 6 0 6 D 1 6 1 6 Hazardous location Class Div 1 Groups A B C D Class Il Div 1 Groups EG Class Ill Non hazardous safe location Strain gauge bridge combination oo MI761 ac Hazardous location equipment see note 1 on page oo MIU64 ac 20 00 q MILZ66 ac F Ground 12 max Non hazardous safe location devices V lt 250V max see note 2 on page 20 Figure 33 Strain gauge bridge combination using MTL761 764 766 barriers Table 15 Entity parameters for Fieldbus barrier MTL791 and terminator FTB1 figure 34 Hazardous location Class Div 2 Groups A B C and D Non hazardous safe location lass Il Div 2 Groups F and A calm MqL791 A B 0 24 0 31 31 ores 1 eri E 0 74 2 97 121 is I VERO moe A AAA E iit pose pola eauipmeni Vi 22V br page 20 Sn p
52. is See clause 4 2 of EN 60079 17 This dls has been designed to meet the requirements of asso ciated electrical apparatus in accordance with EN 50020 and EN50014 This apparatus has been designed and manufactured so as to pro vide protection against all the relevant additional hazards referred to in Annex II of the directive such as those in clause 1 2 7 b Installation a The installation should comply with the appropriate European national and local regulations which may include reference to the IEC code of practice IEC 60079 14 In addition particular indus tries or end users may have specific requirements relating to the safety of their installations and these requirements should also be met For the majority of installations the Directive 1999 92 EC the ATEX Directive safety of installations is also applicable b This apparatus is an associated electrical apparatus and is nor mally mounted in a non hazardous safe area When mounted in a Zonel location the apparatus must be provided with an enclosure which offers an additional degree of protection appropriate to the area classification This apparatus must not be subjected to mechanical and thermal stresses in excess of those permitted in the certification docu mentation this manual and the product specification If neces sary the product must be protected by an enclosure to prevent mechanical damage d The apparatus must not be installed in a position whe
53. istance between the barrier earth busbar and the main power system earth and ensure that it does not exceed the maximum permitted resistance specified in the safety documentation Carefully inspect all cables connected between the barriers and the hazardous area equipment ensure that the cables are the correct type specified in the safety documentation and that they are connected to the correct terminals Ensure that all hazardous area cables are well secured and are segregated from all other cables Ensure that the permitted cable parameters for hazardous area circuits are not exceeded Ensure that all hazardous area apparatus and cables are either earth free or correctly bonded with an equipotential conductor Ensure that all hazardous area cables and cable screens are either terminated at a barrier or connected to the earth rail Ensure that all unused hazardous area cables are connected to a dummy barrier MTL799 or otherwise safely secured to the earth rail ERL7 Ensure that all energy storing devices installed in the hazardous area have been independently certified Inspect all tagging labels and ensure that they display the correct barrier types polarities and circuit loop numbers Carefully inspect all cables connected to the non hazardous safe area equipment and ensure that they are connected only to the non hazardous safe area terminals of the barriers Ensure that no non hazardous safe area equipment is supplied from or
54. kets 2 4 Earth rail 330mm 1 5 Insulating mounting block 2 Figure 22 MK2 kit assembly diagram 6 Tag label assembly 1 7 Tagging strip seal 1 i i i 8 M4 Nyloc nuts 4 6 3 Using SMC7 surface mounting clips E Mu Insert one SMC7 clip into the slot in each end of the barrier pushing 10 Earth rail clamp 2 well into place The barrier can then be fixed to a flat surface using 11 Terminal clamps 16mm 3 screws or bolts up to 4 2mm outside diameter M4 or similar See 12 Terminal clamps 4mm 10 figure 26 6 5 4 MK5 MK12 and MK20 kits assembly 6 4 MK2 mounting kits instructions 6 4 1 MK2 parts list The MKS kit is NOT provided with an earth rail and earth rail o s clamps so take care to follow the special instructions given in d rather Part number Description Quantity than c if using this kit Mounting bracket 1 a Locate the busbar 2 on the fixing studs of the insulating mounting 2 Insulating block 1 blocks 5 making sure both blocks face the same way 3 3 9 x 9 5 self tapping screws 4 A MA washers A b Fit the earth rail mounting brackets 3 onto the studs of each mount 5 Terminal clamp 4mm 3 ing block on top of the busbar and secure using M4 washers 9 and Nyloc nuts 8 The longer ends lie in the safe area 6 4 2 MK2 kit assembly instructions c MK12 and MK20 only Fit the earth rail clamps 10 onto the a Use the four selftapping screws 3 and M4 washers 4 to attach shorter protruding lengths of the earth rail mounting brackets 3
55. lip the TAG7 onto the installation using the lugs located on the top of each mounting block Finally seal the tagging information to the installation by fitting a TGS7 tagging strip seal through the hole drilled previously in the TAG7 tagging strip and the vertical slot in the mounting block The informa tion on the TAG7 label and the barrier model numbers them selves can both be seen at the same time thus making it easy 126 Figure 21 Recommended clearances for mounted barriers shaded portions show areas swept by barrier during installation and removal TGS7 tagging strip seal Top hat rail 7 to EN 50022 35 x 7 5 BS 5584 35x27x7 3 DIN 46277 EBB7 earth busbar IMB7 insulating mounting block G profile rail to EN 50035 G32 BS5825 32 DIN 46277 ERB7 earth rail mounting bracket Figure 20 Installation using the MTL700 700P INM700 10 June 2005 INM700 10 June 2005 6 5 2 MK12 parts list Part number Description Quantity 1 DIN rail 246mm 1 2 Earth busbar 200 5mm 1 3 Earth rail mounting brackets 2 4 Earth rail 215mm 1 5 Insulating mounting block 2 6 Tag label assembly 1 7 Tagging strip seal 1 8 MA Nyloc nuts 4 9 M4 washers 4 10 Earth rail clamp 2 11 Terminal clamps 16mm 3 12 Terminal clamps 4mm 6 6 5 3 MK20 parts list Part number Description Quantity 1 DIN rail 388mm 1 2 Earth busbar 316 5mm 1 3 Earth rail mounting brac
56. lly accepted code of practice e g BS EN 60079 14 2003 in the UK or Recommended Practice e g ANSI ISA RP12 6 for the USA 4 2 Safety checks Table 8 itemises all the important checks which should be carried out to ensure the safety of a barrier installation Diligent use of the checklist will avoid the possibility of any important safety consideration being overlooked when installing commissioning modifying or servicing an installation that uses MTL700 700P Series barriers INM700 10 June 2005 Each item on the checklist is cross referred to the relevant section of the manual to which reference can be made for more detailed information 5 MOUNTING THE BARRIERS ENCLOSED SYSTEMS Although the construction of MTL700 700P Series barriers gives them IP20 protection a higher IP rating and additional protection against mechanical damage and unauthorised modification can be provided by the MT range of enclosures which can mount up to 2 5 12 24 or 32 MTL700 700P Series barriers in the non hazardous safe area n Es gt OLE 210 305
57. mAY Al 000 12V relay WE Highintegrity earth T Figure 35 Switch status transfer circuit using MTL787 9 2 Barrier resistance test not MTL702 705 706 707 707P and 708 If testing a barrier in situ refer to figure 35 and proceed as follows 9 2 1 Disconnect the hazardous area cables from the barrier termi nals 3 and 4 and connect the cables to earth via the earth rail or some other means or alternatively insulate them completely 9 2 2 Disconnect the non hazardous safe area cables terminals 1 and 2 and insulate them completely to prevent them from shorting together to other cables or earth Be careful when handling non hazardous safe area cables the relay contacts in figure 35 for example could be carrying mains voltage 9 2 3 Measure the end to end resistance of the barrier by connect ing a digital multimeter set to a suitable ohms range between terminal 1 and 3 The reading should be slightly less than the maximum end to end resistance quoted in sec tion 3 2 or approximately 10 to 20 higher than the figure specified in the safety description For the MTL787S the reading should be in the range 317 to 3400 9 2 4 Check the serviceability of the diode return channel by select ing the diode test function on the test meter and connect between terminal 4 ve and 2 ve This will measure the forward voltage drop of the MTL787S s three Schottky diodes in the chain and a reading of less t
58. n fitting for the rail enabling easy removal for adding extra ETM7 terminals and one 16mm terminal for making an earth connection Figure 11 Earth rail mounting bracket ERB7 6 1 5 Earth rail ERL7 This rail mounts the earth terminals that are used to earth incoming cables and screens and attaches to the mounting blocks via an ERB7 earth rail mounting bracket It is available in 1 metre lengths and is made of 3 x 10mm nickel plated brass 3 pT Figure 12 Earth rail ERL7 6 1 6 Earth terminal ETM7 Suitable for mounting on ERL7 earth rail to earth incoming cables and screens with up to 2 5 terminals per barrier width possible Supplied Figure 13 Earth terminal ETM7 in bags of 50 6 1 7 Tagging strip TAG7 Provides tagging facilities for up to 64 barriers Supplied in 1 metre AT Figure 14 Tagging strip TAG7 lengths and complete with TGL7 label and six clic rivets for securing purposes 6 1 8 Tagging strip label TGL7 Additional labels for TAG7 tagging strip available separately Supplied in 0 5 metre lengths in packs of 10 6 1 9 Tagging strip seal TGS7 25 Figure 15 Tagging strip seal TGS7 Secures TAG7 tagging strip and label to the installation to prevent unauthorised removal and maintain barrier identification Supplied in bags of ten 6 1 10 Take Care intrinsic safety labels
59. nd either temporarily insu late them or secure them safely to the appropriate terminals of an MTL799 dummy barrier With a digital multimeter set to diode test check that there is an open circuit between the two channels of the barrier terminal 1 to terminal 2 and in at least one direction between the earth studs and terminal 1 and the earth studs and terminal 2 THERMOCOUPLE AND RTD TESTS Thermocouple circuit testing 9 4 2 10 10 1 Hazardous area Non hazardous safe area Compensating cable Non hazardous safe area equipment MTL755 w LE Callibration equipment F High integrity earth Figure 36 Calibrating a thermocouple barrier circuit INM700 10 June 2005 21 Thermocouple test and calibration equipment is not usually certified intrinsically safe and therefore requires special authorisation before it can be used for testing or calibrating thermocouple circuits in hazardous areas To overcome this problem the thermocouple circuits can be protected by using an MTL760 barrier as shown in figure 36 The barrier allows the thermocouple output to be measured without the need to get special authorisation to use the thermocouple test equipment As it is seldom possible to accurately measure the temperatures of thermocouples located in hazardous areas a safe means is required of adjusting the calibration tables to compensate for the plant temperature This can be achiev
60. ng of Section 3 5 for warning of approval changes Country Certificate File No Authority Standard IIB barriers Gps C G IIC barriers Gps A G Approved for Australia SA AS2380 7 1987 Ex2065 Ex2065x Ex ia IIC Canada CSA C22 2 No 157 1R36637 58 1R36637 58 Class Il Ill Div 1 Gps A G LR36637 66 China NEPSI GB3836 1 7 GYJ93106 GYJ93105 ia IIC T6 lia IIB T6 Hungary BKI MSZEN 50 014 amp 020 87B2 018 EEx ia IIC UK BASEEFA to BS 5501 Pts 1 amp 7 Ex92C2375 Ex92C2373 EEx ia IIC CENELEC standards EN 50 014 amp 020 EEx ia IIB UK BASEEFA to BS 5501 Pt 9 Ex92C2376 Ex92C2374 EEx ia IIC CENELEC standards EN 50 039 EEx ia IIB UK BASEEFA BS 5501 Pts 1 amp 7 Ex94C2377 Ex94C2378 EEx ia IIC to CENELEC standards EN 50 014 amp 020 held by MTL India USA FM 3610 Entity J OW2A5 AX J OW2AS5 AX Class Il Ill Div 1 J 1 5WOA3 AX Class 1 Div 2 Gps A D MTL787SP non incendive Certification File No for MTL787SP only 3 6 Enclosure specifications Table 7 Enclosure specifications Obsolete products Specification MT2 MT5 MT12 MT24 MT32 MT20N Max barrier capacity 2 5 12 24 32 20 Construction Polycarbonate glass illed base transparent lid Sheet steel Finish Dark grey base Light grey base Mid grey painted lid fixing 4 captive screws 6 coptive Lift off floppy hinges screws 4 captive screws hasp for padlock Protection dust tight waterproof IEC529 IP65
61. nt reading repeated over a long period of time is indicative that the earth return is sound and likely to remain so If two earth conductors are used as described in section 7 2 the loop resistance should be meas ured as described in that section The reading obtained should not exceed 20 Important note do not attempt to perform a high current earth resistance test unless it is confirmed by the authority in charge of the plant that the plant is gas free 9 FAULT FINDING Most barrier protected systems are relatively simple and can be checked easily for operation However fault finding procedures can be undertaken only after notifying all personnel concerned with plant safety and ascertaining that it is safe to proceed While it is not possible to describe faultfinding procedures for every type of barrier protected circuit there are several guidelines that can help to speed up the process The faultfinding procedures described in this section assume the use of a modern digital multimeter as this is the meter most commonly used However other test meters can be used provided that their characteristics when measuring silicon diodes are known If a diode chain is involved when testing a barrier it is useful to remember that many modern digital multimeters cater for such circuits by the provision of a diode test function These meters usually pass 1mA through the diode and measure the voltage across it When measuring more than two diode
62. nt safety factors that should be considered when using MTL7OO and 700P Series barriers to interface between non hazardous safe and hazardous areas All users should read this section and particularly the checklist before commencing work on the barrier installation For further applicational information concerning the theory and use of shuntdiode safety barriers users are recommended to read the following MTL publications Application Note AN9003 A user s guide to intrinsic safety Application Note AN9007 A user s guide to shunt diode safety barriers MTL7OO Series MTL Intrinsic safety catalogue covering MTL7OO and 700P Series barriers and enclosures parts amp accessories CD700 customer drawings for additional installation informa tion These publications and a comprehensive selection of MTL technical papers TPs can be obtained from the company s Publicity department on request TP1064 1076 1082 1083 and 1106 are particularly relevant Copies of the apparatus and system certificates issued by the various certifying authorities are also available 2 DESCRIPTION MTL700 and 700P Series shuntdiode safety barriers are 1 channel or 2 channel devices that employ intrinsically safe techniques to allow electrical signals to be passed between non hazardous safe and hazardous areas They achieve this by limiting the transfer of energy in one direction to a level that cannot cause ignition of explosive atmospheres Barrie
63. o o oooooooo RR RI mrs 21 10 2 Resistance thermometer detector circuit testing ooon o 21 continued overleaf O 2005 MTL Instruments Group plc All rights reserved INM700 10 June 2005 iii CONTENTS PAGE 11 BARRIR TESTS ooooooooooooooooooonoonorosoroooooos 21 1421 Multimeter tesis td a ss osque tas 22 EEZ ConstantcurrenPlests a play E A A EA aee e E NU vt ES a 22 1453 Tests forthe MITLZO2 25 cts A he US E SU QUE tsi A CN M redes 22 13 4 Tests for iie MIEZO5 arid Z06 isaac iia eda Gee dda I E Pe Ad E ee pv Pe Rr Tg bak Gs 22 Whi 5 Tests for ihe MILZO7 and ZOZR au eser cst mes e UA RAE SEDET Dh rSv hb Vorne arf ican ee citas i 22 VAG Tests for the MILZOB 2s erue pee dee en bis ess al mete t dede des ert Res 22 Ve Testable i duse 34 6 Reha ESL ts hb ae aoe ed aa 22 APPENDIX A ATEX certification informATION ccc ccc ccc ccc n n s sss s ooo 27 2005 MTL Instruments Group plc All rights reserved INM700 10 June 2005 iv MTL700 amp 700P SERIES SHUNT DIODE SAFETY BARRIERS INM700 10 June 2005 MTL7OO Series shunt diode safety barriers con t int safe ri Div ABCD g SCHE gor Qni ow mA ms veras IN y oves Aen 1950 1 INTRODUCTION This instruction manual contains the information necessary to install maintain faultfind and test MTL700 and MTL7OOP Series shuntdiode safety barriers Section 4 of the manual contains a checklist which highlights all the importa
64. on 6 4 gives the assembly instructions for the mounting kits 6 1 The MTL700 and 700P Series accessories range 6 1 1 Earth busbar EBB7 Used for mounting and earthing MTL700 700P Series barriers Available in 1 metre lengths in nickel plated brass 94 4 gt 145 e cie e a coo o ofe 0 0 oc Oo 0 6 EE Figure 8 Earth busbar EBB7 6 1 2 Insulating mounting block IMB7 Used for mounting EBB7 earth busbars and insulating them from panel structural earth to prevent invasion by fault currents IMB7s are sufficiently high to provide tagging and earthing facilities for MTL3000 and 2000 Series interface units if required They can be mounted on a flat surface top hat rail to EN50 022 35 x 7 5 BS 5584 35 x 27 x 7 3 DIN46277 or G profile rail to EN50 035 G32 BS 5825 32 DIN46277 6 1 3 Insulating mounting block SMB7 An alternative to the IMB7 to reduce the overall height of the installation to 97mm Mounts on a flat surface only INM700 10 June 2005 NEED M4 x 20 fixing screw 21 1 Figure 9 Insulating mounting block IMB7 M4 x 20 fixing screw Figure 10 Insulating mounting block SMB7 6 1 4 Earth rail mounting bracket ERB7 For supporting and electrically connecting the earth rail to the busbar it mounts over either type of mounting block Made of 3 x 10mm tin plated brass the ERB7 is supplied with one bolt dow
65. r usage of earthing terminals in enclosures For enclosures all cables will need to be connected via suitable glands not supplied as described below 7 1 Glanding cables into enclosures 7 1 1 MT2 and MT5 Two pre drilled 20mm gland holes are provided in the base of each enclosure fitted with push in blanking plugs 7 1 2 MT12 The enclosure has detachable top and bottom gland plates for drilling by the user This can be done with the gland plates in situ or removed if preferred To remove the gland plates firmly press the plate retaining lip on the inside of the enclosure to release the front edge of the plate Then gently lever the plate retaining lip at the back of the enclosure to release the rear edge of the plate Note that the embossed arrow on the inside of the gland plate always points towards the front of the enclosure when fitted and then drill the gland holes in the required positions The gland plates snap back into position 7 1 3 MT20N This enclosure has detachable top and bottom gland plates for drilling by the user This can be done with the gland plates in situ or removed if preferred To remove the gland plates simply unbolt them from the enclosure 7 2 To ensure correct and safe operation of the barrier system it is vitally important that the installation is earthed properly All MTL700 700P Series barriers should be connected to a high integrity earth via a copper conductor The resistance of this condu
66. rd barriers are to be connected to a non hazardous safe area power supply If the supply is connected the wrong way around the barrier fuse will blow INM700 10 June 2005 and the unit will need replacing MTL702 705 706 707 707P and 708 overvoltprotected barriers cannot be damaged in this manner For standard barriers ensure also that the supply voltage does not exceed the working voltage Vwkg of the barriers as specified in section 3 2 Do not connect barriers to non hazardous safe area equipment that is supplied from or contains a source of potential with respect to earth that exceeds 250V rms or 250V dc under normal or fault conditions unless specifically permitted to do so by the safety documentation Connection to non hazardous safe area equipment fed from a three phase 440V neutral earthed supply is permissible All unused non hazardous safe area cables should be secured safely to terminals 1 and 2 of an MTL799 dummy barrier or by some other suitable method 7 4 Connecting hazardous area cables to barriers The hazardous area cables must be connected only to terminals 3 and 4 of MTL700 700P Series barriers They should be segregated from non hazardous safe area cables and routed to the hazardous area equipment via the hazardous area loom conduit or trunking Before making any connections ensure that all energy storing devices i e devices that are not classified as simple apparatus used in th
67. re it may be attacked by aggressive substances and must be protected fon excessive dust moisture and other contaniments by an enclosure Inspection and maintenance a Inspection and maintenance should be carried out in accordance with European national and local regulations which may refer to the IEC standard IEC 60079 17 In addition specific industries or end users may have specific requirements which should also be met b Access to the internal circuitry must not be made during operation c f the outer enclosure of the aes needs to be cleaned this should be done with a cloth lightly moistened by a dilute mixture of detergent in water Repair a These barriers must not be repaired A barrier must be replaced by an equivalent certified product Marking MTL7OO Series barriers carry a certificate number as detailed in Table 12 Each device is also CE marked with the Notified Body Identification Number of 1180 and carries the following information Company logo Company Name and Address Product Number and Name Certificate Number s Ex Classification where applicable f Schematic diagram g h This manual applies to products date marked 2002 or later Safety description parameters Ambient temperature range INM700 10 June 2005 27 Figure A1 Typical MTL7OO Series barrier label MTL 755ac Shunt diode safety barrier 3v 100 Max amb 1 1 GD EEx ia IIC 3V 109 temp 60 C 20 C lt Ta lt 60 C Uo 3V lo
68. rier circuit 11 3 Tests for the MTL702 Comprehensive testing requires specialised equipment however an effective test which will confirm whether the unit is operating correctly is shown in figure 39 The two ammeters used should be able to measure a signal of between 4 and 20mA with fairly good accuracy Connect them as shown initially in the lead to terminal 3 and note if any error is present between the two readings Then move one of the meters to the terminal 2 lead ensuring correct polarity and check that the readings on the two meters are approximately equal 20 to 35V de Transmitter simulator Figure 39 MTL702 test circuit INM700 10 June 2005 22 11 4 Tests for the MTL705 and 706 Owing to the nature of these units comprehensive testing requires specialised equipment beyond the scope of on site checks However an effective test which will confirm whether the units are operating correctly is shown in figure 40 Connected in this manner ammeter 1 measures the transmitter simulator current of between 4 and 20mA flowing from terminal 4 and the safearea load current flowing to terminal 4 simultaneously Since these two currents are equal and opposite the resultant reading on the ammeter should be virtually zero Ammeter 2 is used to verify the presence of the 4 to 20mA transmitter signal 20 to 35V de 2500 Transmitter simulator
69. rque of 2 3Nm using the TQS7 torque spanner or other suitable wrench Note that these Nyloc nuts will lose their anti vibration feature after being tightened released several times so if possible avoid undoing them once they have been tightened Ensure that the barriers are mounted such that their hazardous area terminals are adjacent to the row of terminals mounted alongside the busbar or in the case of the MT5 the three small terminals mounted on the end brackets 5 2 Mounting the enclosure Depending on the model utilised there are up to three different methods of mounting enclosures and these are illustrated in figure 7 and described later The enclosure specifications section 3 6 details mounting methods dimensions and kit provided for each model Care should be taken when mounting enclosures to ensure the internal temperature does not exceed the maximum permitted ambient temperature for the barriers i e 60 C For this reason enclosures should not be mounted in areas where they will be subject to direct sunlight or other sources of heat INM700 10 June 2005 5 2 1 Corner screws plugged knockout holes not MT20N With this method enclosures are mounted from the front using screws or bolts not provided First using a small screwdriver pierce the corner knockouts from the rear of the enclosures not applicable on MT2 and MT5 holes are already provided Then from the front of the enclosures insert suitable scre
70. rs that are connected in series with lines going to a hazardous area will protect wiring and equipment in that area from any faults occurring in the non hazardous safe area thus permitting a wide range of measurement and control operations to be undertaken safely Applications of MTL700 and 700P Series barriers include the protection of installations containing non energy storing uncertified INM700 10 June 2005 devices such as switches thermocouples resistive sensors photocells and LEDs or separately certified energy storing apparatus for example ac sensors transmitters and P converters The barriers also enable maintenance work or calibration to be carried out without further precautions and they permit non hazardous safe area equipment to be worked on safely as and when necessary with the minimum of restriction A range of five polycarbonate enclosures is available to provide environmental protection for barriers where required and a Type N approved steel enclosure also is available to permit the barriers to be installed in Zone 2 areas Enclosures and other accessories are fully described in this manual 3 BARRIER SPECIFICATIONS 3 1 The MTL700 and 700P Series The series consists of a carefully tailored range of application orientated models most polarised positively but some negatively and some non polarised There is also a dummy barrier Basic circuits specifications and approvals for each model are giv
71. s terminals 1 no tion then then amp ve lead amp ve lead amp 2 both ve to 3 ve to 3 to term 1 to term I 1 polarities ve to 4 ve to 4 amp then 2 amp then 2 10pA 20mA Min Max Min Max 786 28V diode co x3 co B x2 co 25 5V 28 0V 26 1V 28 4V 28V 300W 3 1 317Q to 3170 to co B x2 co 25 5V 26 3V 26 1V 26 7V e 9 3400 3400 787 28V diode c pi x3 oo oo 25 5V 28 0V 26 1V 28 4V 28V 3000 i 317Q to 3170 to co B x2 co 25 5V 26 3V 26 1V 26 7V 3400 3400 7878 28V diode co B x3 co B x2 co 24 5V 25 7V 247N 26 1V Schottky 28V 2340 2400 to 2400 to co B x2 co 24 5V 25 7V 24 7V 26 1V 2570 2570 787SP 28V diode co x3 co B x2 co 24 5V 25 7V 24 7V 26 1V Schottky Table 29 Tests for fieldbus barriers This barrier has to provide balanced operation of the fieldbus with respect to earth It therefore has identical positive and negative polarity channels A fieldbus terminator is also included in the barrier Multimeter tests Constant current tests Barrier data End to end Channel resistance Diode test isolation Voltages obtained when test test applying constant current to terminals 1 ve and Connect Connect Connect then terminals 2 ve between ve lead ve lead Connect Connect and earth studs MTL Safety EO term ls 1 amp 3 to earth to earth ve lead
72. s 3 258 24 5 26 5 80 28 diode Controller outputs 0 9V 160 24 5 26 5 80 Switches 4 2 3 5 Approvals Changes may have occured since this document was printed Check our web site for latest information http www mitl inst com Table 5 Approvals for MTL700 Series barriers Country Certificate file no Authority Standard MTL710 to 796 MTL702 MTL706 MTL707 708 787S Approved for Argentina IAP CA 4 01 1989 INTICITEI 92A001 INTICITE 92A001 INTICITEI 92A001 INTICITEI 92A001 Ex ia IIC Australia QMD CMA 1925 1981 QMD 85 6001 XSU QMD 85 6124 XU Mining Australia NSW M CMRA 67 1982 MDA Ex ia 1321 MDA Ex ia 1411 MDA Ex ia 1321 MDA Ex ia 1321 Coal and shale mines Australia SA AS2380 7 1987 Ex 562 Ex 692 Ex 562X Ex 562X Ex ia IIC Brazil NBR 8447 84 CE Ex 221 92a CE Ex 220 92 CE Ex 221 92 BR Ex a ib IIC Canada CSA C 22 2 No 157 1R36637 14 1R36637 16 LR36637 26 LR366 37 20 Class II Ill Div 1 AG China NEPSI GB3836 1 7 GYJ93105 GYJ93105 GYJ93105 GYJ93105 ia IIC T6 Czechoslovakia FTZU CSN 33 0380 J02033 J02033 02033 JO2033 Ex ib IIC Denmark DEMKO EN 50 020 R75916 EEx ia IIC Hungary BKI MSZ 4814 7 77 87B2 018 87B2 018 87B2 018 87B2 018 Ex ib IIC Japan TIIS 1979 Rec Pract C10619 to C10636t 39286 Groups 2 and 3a G5 Korea KRS LNDO3065 EL001 LNDO3065 ELOO1 LNDO3065 ELOO1 LNDO3065 ELOOT EEx ia IIC Tamb 60 C Poland KDB PN 84 E 08107 KDB Nr 21
73. s cut a length of busbar with the required num ber of mounting positions plus two extra for the mountings For 26 to 50 barriers three extra mounting positions are required For 51 to 64 barriers four extra positions are required 6 2 2 Position the busbar on the fixing studs of the IMB7 or SMB7 mounting blocks The blocks should face the same way and be located not more than 25 spaces apart 6 2 3 6 2 4 6 2 5 6 2 6 6 2 7 Fit the ERB7 earth rail mounting brackets also onto each mount ing block s studs on top of the busbar ensuring that the large terminals are on the hazardous area side Tighten the IMB7 or SMB7 s fixing nuts using the TQS7 torque spanner If SMB7 mounting blocks have been used fix the whole assembly to a flat surface using the two screws located in each block Installations using IMB7s can be similarly mounted or alternatively on top hat or G profile rail For rail mounting check that the swing nuts are turned out of the way and locate the IMB7s on the rail As the appropriate screws are tightened the swing nuts pivot into position under the edges of the rail thus securing the assembly The two angled screws are for G profile rail and the two vertical screws for top hat rail It may be necessary to remove the surface mounting screws from the IMB7s to achieve a flush fitting onto the rail Mount the barriers on the busbar in the required positions tightening all fixing studs using the TQS7 torqu
74. t see note 1 on page 20 Hazardous location equipment see note 1 on page 20 for each channel Ground 19 max Y Non hazardous safe location devices V 250V max see note 2 on page 20 Note Ground returns for each piece of hazardous location equipment must be run separately Figure 30 2 channel barrier connection with separate ground return Table 12 Entity concept parameters for 2 channel MTL70O barriers with optional ground return figure 31 Hazardous location Class Div 1 Groups A B C D Class Il Div 1 Groups EG Non hazardous safe location Class Ill 2 channel barriers optional ground return Barrier Voc Isc Ca La i model no 2 channel barrier MTL V mA pF mH WB a assai cose ripe 707 28 1 93 0 12 4 0 see note 1 on page see note 2 on 20 Optional page 20 758 8 1482 60 0 02 Sa 7878 28 7 93 0 11 4 0 md F Ground 10 max Figure 31 2 channel barrier connection with optional ground return INM700 10 June 2005 17 Table 13 Entity concept parameters for strain gauge bridge systems using MTL761 764 barriers figure 32 Group Ca La pF mH A amp B 0 2 0 24 Hazardous location Class Div 1 Groups A B C D 1 Class Il Div 1 Groups EG Class Ill Non hazardous safe location Strain gauge bridge combinat
75. t 20 C channels track within 0 15W from 20 to 60 C b ac version 24 5V e ac version 11 2V t For new designs use MTL706 c ac version 7 4V d ac version 26 1V Diagrams show positive versions All diodes reversed on negative versions Additional diodes fitted on ac versions Patents for MTL787S UK Patent No 2210522 USA Patent No 4860151 INM700 10 June 2005 Table 4 Basic circuits and specifications for the MTL70OP Series higher power barriers for notes 1 to 6 see 3 2 1 Terminology 1 2 3 4 5 6 Model Gas Safety Polarities Basic circuit Max Vwkg Vmax Fuse No group description available Applications end to end at rating resistance 10 1 pA MTL V 9 mA ac hazardous safe Q V V mA 707P IIB 28 164 171 Transmitters See 3 3 additional 35 50 15 diode Controller outputs specifications 710P IIC 10 33 300 v Y 8V dc systems 42 8 0 9 2 200 715P IIC 15 50 291 v 12V dc systems 3 1 60 12 5 13 8 200 722P IIC 22 101 213 v 18V dc systems 121 15 20 0 100 728P IIC 28 234 119 v Controller outputs 253 24 5 26 0 100 Solenoid valves 4 2 729P IIB 28 164 171 Controller outputs 184 24 5 26 0 100 Solenoid valves 3 1 761P IIC 9 350 25 Vv Strain gauge 384 7 0 8 1 50 9 350 25 bridges 384 7 0 8 1 50 766P IIC 12 75 157 Vv Strain gauge B 93 9 8 11 3 100 12 75 157 bridges C 93 9 8 11 3 100 2 787SP IIC 28 234 119 Transmitter
76. t voltage of appropriate polarity that can be applied continuously between the non hazardous safe area terminal of any barrier channel and earth at 20 C without blowing the fuse For basic barriers it is specified with the hazardous area terminal open circuit if current is drawn in the hazardous area the maximum voltage for these barriers may be reduced The ac channels of basic bar riers and most channels of overvolt protected barriers withstand voltages of the opposite polarity also see circuit diagrams 6 Fuse rating This is the greatest current that can be passed con tinuously for 1000 hours at 35 C through the fuse 7 Star connection In star connected barriers the two channels are interlocked such that the voltage between them cannot exceed the working voltage Vwkg 8 UM not shown on the tables UM defines the maximum voltage that can be applied to the non intrinsically safe connection facili ties of associated apparatus without invalidating intrinsic safety For all MTL700 700P barriers UM is 250V rms or dc with respect to earth 3 3 3 3 1 MTL702 additional specification Supply voltage 20 to 35V dc positive w r t earth Voltage available for transmitter and lines at 20mA Vsupply minus 8V limited at 16V Voltage available for load at 20mA Vsupply minus 5V Load resistance 850Q maximum Output impedance to load gt 1MQ Calibrated accuracy at 20 C with 250Q load 0 05 of maximum ou
77. ted on a flat surface using the fixing lugs provided On models MT2 and MT5 the two plastic lugs can be positioned on either pair of opposite sides as shown in figure 6 They are attached to the rear of the enclosure by the self tapping screws provided On models MT12 and MT24 the plastic lugs are positioned one in each corner and each can be attached in any one of three positions see figures 6 and 7 The lugs are attached to the rear of the enclosure using the screws provided Model MT32 is similar but uses six lugs one in each corner and two midway along the enclosure s length This extra lug on each side should be fixed at rightangles to the enclosure s side in either one of the two mounting holes Model MT20N has fixed mounting lugs whose centres are shown in figure 6 MOUNTING THE BARRIERS UNENCLOSED SYSTEMS To simplify installation in circumstances where enclosures are not required the parts needed are available either separately or as complete mounting kits for specified numbers of MTL700 700P barriers The range of accessories available for mounting MTL700 700P Series barriers as unenclosed systems is detailed in section 6 1 MTL certified customer drawings CD7O1 Series containing full specifications of each item are also available Section 6 2 details the simple step by step procedure for constructing a comprehensive barrier mounting earthing and tagging installation using the separate part accessories and secti
78. ter than 1 18W e The sum of all devices unprotected input capacitance Ci plus the cable capacitance must be equal to or less than Ca for the appli cable Gas Group in Table 15 fJ The sum of all devices unprotected input inductance Li plus the cable inductance must be equal to or less than La for the applicable Gas Group in Table 15 Note 2 Note 3 Note 4 Note 5 Note 7 Note 8 Note 9 INM700 10 June 2005 Table 19 Entity concept parameters for two channel MTL7OOP barriers with sep arate ground returns figure 30 and notes 6 to 9 Barrier Groups Voc Isc Each channel Each channel model No V mA Ca pF La mH MTL 707P return C E 14 1 0 2 85 1000 707P return D F G 14 1 0 7 62 1000 707P signal C E 26 4 160 0 49 6 21 707P signal D F G 26 4 160 1 31 11 5 761Pac A B 9 0 25 4 89 54 8 761Pac C E 9 0 25 14 6 194 0 761Pac D F G 9 0 25 39 1 475 0 766Pac A B 11 5 149 1 87 1 25 766Pac C E 11 5 149 5 63 7 16 766Pac DEG 11 5 149 15 0 13 4 Note 12 For guidance on installation see ANSI ISA RP12 6 and the USA National Electric Code Note 13 The barrier must be installed in enclosures meeting the requirements of ANSI ISA S82 and the USA National Electric Code Note 14 Use FMRC approved or NRTL listed dust ignition proof enclo sures appropriate for environmental protection in Class Il Division 2 Groups F and C and Class Ill Hazar
79. test function is used for the diode tests channel isolation tests and for the end to end resistance tests for diode return channels 11 2 For these tests a constant current generator is required The generator must be capable of supplying 10pA 20mA and 40mA currents from a 30V source Ideally a purpose built current generator should be used but a conventional laboratory power supply can be used as shown in figure 38 The current is measured on one multimeter and trimmed by adjusting the output voltage of the power supply indicated on a second multimeter When using a constantcurrent generator for testing MTL7OO Series barriers the following points should be noted Multimeter tests Constant current tests 11 2 1 The current should be limited to 50mA to avoid damaging the barriers 11 2 2The accuracy of the current is not critical and can therefore vary by 15 11 2 3 The test leads must be connected securely to the barrier ter minals 11 2 4 The use of a high resistance in series with the barrier will give more stable results and make it easier to set the required current 2 channel laboratory power supply Current limited to 50mA 0 30V variable 0 30V variable switch e Digital multimeter current 3MQ Digital multimeter voltage 10pA Current selector To barrier on test Y Figure 38 Calibrating a thermocouple bar
80. tput including non linearity and hysteresis Zero temperature drift lt 0 005 of maximum output per C Span temperature drift lt 0 005 of maximum output per C Supply current 8 to 40mA 10mA maximum at 20V 8 to 40mA 20mA maximum at 35V Additional specifications 60mA max o 35V max O o 100mA Current mirror 4 20mA Eva Regulate 4 20mA 4 DO Queer 50mA 50mA 2 t Pu ip m LA i 0 OY 1 e o Figure 1 MTL702 basic circuit 3 3 2 MTL706 705 additional specification Supply voltage 20 to 35V dc positive w r t earth Output current MTL706 4 to 20mA MTL705 0 to 20mA Voltage available for transmitter and lines 15V minimum at 20mA with 22V supply 15 5V typical at 20mA with 24V supply Note voltages are negative w r t earth Load resistance MTL706 2500 5 MTL705 3000 can be greater if reduced transmitter voltage is acceptable Accuracy 2pA under all conditions Supply current 35mA typical at 20mA with 24V supply 40mA maximum at 20mA with 35V supply 35V max 40mA max Id 1 F o 50mA Current limit gt Regulate Negative AAA 4 20mA PA 4 20mA 3 gt A pO AF Eo 50mA 50mA 2 Te 2500 E 45 ly Lo ov e o Figure 2 MTL706 basic circuit 3 4 Common specification Ambient temperature an
81. users to carry out additional tests to those given in section 8 if they suspect the performance of the barriers Barriers which pass these tests satisfactorily are not likely to incur an unacceptable level of risk or cause a circuit malfunction From tables 26 to 33 it can be seen that there are two types of test a simple test using a digital multimeter to test barriers without the need of having to remove them from the earth busbar and a more comprehensive bench test using a constant current source to establish the breakdown characteristics of barriers BASEEFA certification requirements concentrate on high current tests but in many ways the leakage current tests given in this section are a more satisfactory method of testing suspect diodes If a complete functional check of a barrier is required then the multimeter tests and constant current tests described in section 10 1 and 10 2 should be undertaken However for most purposes the multimeter tests alone will suffice The MTL702 705 706 707 707P and 708 cannot be tested in the same manner as ordinary 700 Series barriers separate tests for these models are detailed in sections 11 3 to 11 6 The use of a digital multimeter for testing barriers is described in section 9 The section 11 tables assume that the multimeter is selected to a suitable ohms range for the end to end resistance tests except for diode return channels and for the continuity tests and that the multimeter diode
82. ws or bolts through the 5mm diameter apertures made by the removal of the knockouts and fix the enclosures into position The mounting dimensions are shown in figure 6 Finally on MT12 MT24 and MT32 only insert the plastic sealing plugs provided into the holes above the screws and push them firmly into place to seal the knockout apertures so as to preserve the enclosure s IP65 integrity d ak Frontixi fa Ju SEN D lo Zo P Rearfixing 9 Fo 4 screw di ZA Ss EM Enclosure Figure 7 Method of mounting a typical enclosure Table 8 Checklist Item No Check section Refer to 1 Before commencing the installation ensure that the safety documentation confirms that the proposed system is fully certified if applicable and complies with the recommendations contained in the relevant sections of BS 5345 for the gas group temperature classification and area classification required Ensure that the barriers installed are of the correct type and polarity as specified in the safety documentation Ensure that all barriers are mounted the right way around Ensure that all barriers are securely mounted on the earth busbar by checking the tightness of both mounting nuts on each barrier with a torque spanner Ensure that all barriers are properly earthed in accordance with the safety documentation and in compliance with the recommendations contained in BS 5345 Part 4 Measure the res

MTL700 and 700P Series shunt

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