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Related Manuals for Dwyer Instruments MTL7700 Series
Summary of Contents for Dwyer Instruments MTL7700 Series
- Page 1 MTL7700 Series Shunt-diode safety barriers Instruction Manual INM7700...
- Page 2 INM7700-6 Jan 2010...
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Page 3: Table Of Contents
MTL7700 Series – barrier ranges ........ - Page 4 INM7700-6 Jan 2010...
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Page 5: Overview
MTL700 Series. Section 3 includes a checklist of essential safety factors that must MTL7700 Series barriers are 1-, 2- or 3-channel devices that use be considered when using MTL7700 Series barriers as intrinsically intrinsically safe explosion-protection techniques to pass electrical safe (IS) interfaces between safe and hazardous areas. -
Page 6: Mtl7700 Series - Accessories
Power accessories (figure 3) BPL7700 Power link for feeding 24V dc to a maximum of MTL7700 Series barriers mount directly onto DIN-rail. A 40 barriers in a single column from an MTL7798 comprehensive selection of mounting, tagging, power and earthing power feed module or MTL7799 Dummy accessories is available. -
Page 7: Safety Considerations
MTL7700 Series improperly mounted barrier will stick up slightly. Instructions for Safe Use 2: Once an MTL7700 Series barrier is fitted, its mounting/earthing Safety checks foot grips the DIN-rail strongly in order to maintain positional stability Table 2 itemises the essential checks that should be carried out to and create a high-integrity earth bond. - Page 8 Figure 4: Dimensions (mm) of an MTL7700 Series barrier by the safety documentation and that they are connected to the correct terminals. Mounting accessories Section 4.3.1 to 4.3.
- Page 9 IS earth connection to the earth screen on any individual barrier: this is MANDATORY. See also section 5.3. Figure 6: Clamping an MTL7700 Series barrier on to a DIN-rail ETL7000 terminals are attached to the rail as follows. Ensure the same security of the earth connection to the rail as for the barriers themselves (see section 4.2):...
- Page 10 Note: Early versions of TH7700 are hinged on two small locating M6 X 16 pins. Later versions are hinged by locating the clips at the hinged end into the rectangular appartures on the barrier body. The later design High - profile can be retrofitted on early modules by removing the hinge pins with DIN rail a knife.
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Page 11: Wiring Connections
WIRING CONNECTIONS Up to 40 barriers can be linked using the power links. The link itself is supplied from a power feed module (MTL7798). The MTL7798 power feed module is provided with a trip circuit which protects the General barriers by switching off their supply if a fault (such as an This section describes wiring connections as follows: overvoltage) occurs in the power source. - Page 12 Hazardous Safe Area Area MTL7798 (MTL7799) Power To IS earth Connections Loop power to opposite ends to allow module removal ETL7000 earth terminal Figure 15: Plant earth connection to ETL7000 earth terminal Logic signal MTL7787+ MTL7787P+ 5.3.3 Earthing an earth rail assembly On installations which include earth rail assemblies (see section 4.3.4) an earth conductor, normally copper wire with a cross- Power Bus...
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Page 13: Connections To Dummy Barriers
Where this possibility General cannot be avoided, then barriers associated with bonded Circuits in all MTL7700 Series barriers are encapsulated and so systems should be mounted on a separate DIN-rail from those on cannot be repaired. However, provided they are correctly installed which other barriers are mounted. -
Page 14: Fault-Finding
Figure 20 depicts a typical switch-status transfer circuit protected by an MTL7787+ barrier which illustrates some of the fault-finding techniques discussed in this section. To determine the serviceability of MTL7700 Series barriers, follow the steps described in sections 7.2 to 7.3. INM7700-6... -
Page 15: Power Supply Check
Repeat the test with the connections reversed (ie, terminals 4 (–ve) and 2 (+ve) for an expected reading of ∞ for the reverse MTL7700 Series barriers do not need to be subjected to routine voltage drop. testing if they are in normal use. Generally, the inspection tests described in section 6 are more than adequate. -
Page 16: Tests For Active Barriers
(figure 23) will serve. The current is measured by one multimeter and trimmed by adjusting the output voltage of the power supply indicated on the second multimeter. When using a constant-current generator for testing MTL7700 Series Safe-area equipment barriers, note the following points:... - Page 17 8.3.3 Tests for MTL774x Bussed Power V s + The MTL774x range are switch/prox input barriers with a choice of changeover relay contacts or a solid state switch acting as the safe area interface. Relay contacts provide a universal interface capable of switching a wide range of signals including ac, low level and high Channel 1 Channel 1...
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Page 18: Test Tables For Passive Barriers
Test tables for passive barriers Tables 4 to 10 detail the tests for all MTL7700 Series ‘passive’ barriers. In the ‘diode test’ columns, the figures adjacent to the diode description indicate the number of forward-biased diodes used in the barrier chain. Using the multimeter diode test function and knowing the diode voltage drop figures (approximately 0.6V for each Zener diode and 0.3V for each Schottky diode), the expected reading across the diode chain can... - Page 19 BARRIER DATA MULTIMETER TESTS CONSTANT-CURRENT TESTS Safety End-to-end Diode Diode Terminal Terminal model Description Resistance Test Test Voltage Voltage Ω Ω @ 10μ μ A @ 20mA Ω Ω Min Max ∞ ∞ 7728ac 28 300 93 26.7 25.6 27.2 Table 6: Single channel BARRIER DATA MULTIMETER TESTS...
- Page 20 BARRIER DATA MULTIMETER TESTS CONSTANT-CURRENT TESTS Safety End-to-end Diode Diode Terminal Terminal model Description Resistance Test Test Voltage Voltage Ω Ω @ 10μ μ A @ 20mA Ω Ω Min Max ∞ 7787+ 28 300 93 26.6 27.4 26.7 27.6 ∞...
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Page 21: Appendix A: Typical Wiring Connections For Specific Applications
APPENDIX A: TYPICAL WIRING CONNECTIONS Hazardous Safe FOR SPECIFIC APPLICATIONS. Area Area Power Bus Hazardous Safe Area Area Power +26.6V Logic signal Power +26.6V Power Bus MTL7789+ Logic signal Power +26V Signal MTL7706+ MTL7787+ 1-5V MTL7787P+ Figure A5: 2-channel switch inputs 4 -20mA 250W MTL7788+... - Page 22 Hazardous Safe Hazardous Safe Area Area Area Area +26V MTL7728+ MTL7761ac --7V Figure A9: Analogue output Sense MTL7764ac — Hazardous Safe Area Area Power Bus 620Ω +22.9 - 30V Output (mV) 10kΩ MTL7761ac MTL7745 CH 1 Figure A10: Single channel switch/proximity input with Line Figure A13: Strain-gauge bridges Fault Detect Hazardous...
- Page 24 MTL Instruments Pty Limited MTL Italia srl 9 /12 Billabong Street Via Cantù 11 Stafford I - 20092 Cinisello Balsamo MI Queensland 4053 Italy Australia Tel: +39 (0)2 61802011 Fax: +39 (0)2 61294560 Tel: + 61 1300 308 374 Fax: + 61 1300 308 463 E-mail: info@mtl-inst.it E-mail: enquiries@mtlaus.com.au MTL Instruments KK...
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