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Summary of Contents for Moeller PS 4
- Page 1 EMC Engineering Guidelines For Automation Systems PS 4 PS 416 04/97 AWB 27-1287-GB 1st edition 04/97 © Moeller GmbH, Bonn Author: Werner Albrecht Editors: Klaus Krüger, Thomas Kracht Translator: Chris Baker, Terence Osborn...
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Page 2: Table Of Contents
Use of screened cables Incoming external screen cables Inter-building wiring system: screening the line 3 Earthing Devices PS 4 compact PLCs PS 416 series of modular PLCs Avoiding RF interference signals, ferrite ring 4 Installing a Screen Line Inside a Control C abinet... -
Page 4: Fundamentals Of Interference-Free Design
Fundamentals of Interference-Free Design General comments In order to meet EMC requirements the wiring of systems using the PS 4 and PS 416 must observe certain rules: In particular a uniform reference potential must be created. The reference potential is formed by the totality of all... -
Page 5: Low-Impedance Connection
Fundamentals of Interference-Free Design Low-impedance A low-impedance connection is achieved in the connection following way: A large-area, low-impedance metal-to-metal connection The use of flexible earthing strips Short connecting wires with a large surface area and contact surface A conventional PE conductor with a small cross- section will not be adequate. -
Page 6: Construction Of Reference Potential Surfaces
Construction of Reference Potential Surfaces The construction of the reference potential surfaces is described below - from control cabinet design through to connecting up equipment. Control cabinet design The control cabinet housing is a part of the reference potential surface. To be sure that you have an adequate reference potential surface you will need to observe the following rules:... - Page 7 Construction of Reference Potential Surfaces Figure 1: Installation Connect all inactive metal parts (cabinet doors, side parts and so on) to the reference potential surface ensuring you have a large area and low impedance connection. Connect mounting plates together so that they then form a common reference potential surface.
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Page 8: Mounting Plates, Ci Distribution Boards
Mounting plates, CI distribution boards cable clip must sit snugly around the entire circumference of the cable screen. Connect the external protective circuit (potential to earth) to the control cabinet reference potential (internal protective conductor bar) with a large- area and low-impedance connection. Protect the all chassis earth connections against corrosion. -
Page 9: Fitting Top-Hat Rails
Construction of Reference Potential Surfaces Mounting Plate Carrier rail Figure 2: Large-area connections Divided mounting plates as a whole are inactive metal parts and thus form a constituent part of the reference surface. This is why they must also be connected together with low-impedance connections (for example, using galvanized earthing strips). -
Page 10: Use Of Screened Cables
Use of screened cables Use commercially available top-hat rails that are corrosion-proofed. Mounting plate Carrier rail Top-hat rail Top-hat rail Figure 3: Fastening the top-hat rail Use screws or rivets for a large-area and low- impedance connection of the top-hat rail with the support system. -
Page 11: Incoming External Screen Cables
Construction of Reference Potential Surfaces The cable screen must be earthed as close as possible to the system's source of interference. Always connect both ends of the cable screen to potential to earth. Do not forget here that the potential to earth may have different potentials at the earthing positions. - Page 12 Incoming external screen cables Busbar Top-hat rail integrated srew Top-hat rail Busbar Remove the insulation of screened lines at the contact point. Make sure that the screen braid does not get broken or damaged. It is important that the connection of the busbar with the reference potential surface is short and of low impedance (no insulated segments)!
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Page 13: Inter-Building Wiring System: Screening The Line
Construction of Reference Potential Surfaces Make a new braided screen contact as close as possible to the device. Inter-building wiring For lightning protection in accordance with system: ENV 50 142 you should use a suitable surge arrester. screening the line Surge arresters manufactured by Messrs Dehn, for example, are suitable here. -
Page 14: Earthing Devices
Earthing Devices PS 4 compact PLCs Installation on top-hat rail DC devices AC devices PS4/EM4 Figure 4: Device earthing when installing on top-hat rail Top-hat rail Functional earthing (with DC devices) Protective and functional earthing (with AC devices) Protective conductor bar... - Page 15 Earthing Devices earth should be connected as short as possible to the protective conductor bar with a 1.5 m core cross-section. Installation on mounting plates DC devices AC devices PS4/EM4 Figure 5: Device earthing when installing on mounting plates Mounting plate Cable lug Functional earthing (with DC devices) Protective and functional earthing (with AC devices)
- Page 16 PS 4 compact PLCs The conductor is connected to the mounting plate via a highly conductive connection which should be as flat as possible; for example, a cable lug. Connect the fixing feet to the mounting plate with a low-impedance connection.
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Page 17: Ps 416 Series Of Modular Plcs
Earthing Devices PS 416 series of Rack modular PLCs You should connect the rack to the carrier system (mounting plate, rack frame, hinged frame and so on) with a low-impedance connection of maximum area. Connect the rack to the protective conductor bar. The protective earthing cable used here must have a cross-section of 6 mm... -
Page 18: Avoiding Rf Interference Signals, Ferrite Ring
Avoiding RF interference signals, ferrite ring Avoiding RF If RF interference signals are to be avoided, when interference signals, installing the assemblies you will need to fit the data ferrite ring lines – and possibly also the supply lines – with ferrite rings. - Page 19 Earthing Devices The ferrite ring is not included in the scope of supply of the cards. Figure 7: Fitting the ferrite ring Cards Ferrite ring P S416-ZBX-405 Cable ties Screen connection Screened data line Supply line Potential equalisation bar...
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Page 20: Installing A Screen Line Inside A Control C Abinet
Installing a Screen Line Inside a Control C abinet PS 4 compact PLCs Figure 8: Screen connection to reference potential surface...
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