Servo Drive Installation Best Practices
Contents
1. Ground Bus Braided Ground Strap E Ground Grid or Power Distribution Ground 24V Power Supply Installations Power supplies are inherently associated with two EMI related issues e The use ofa common power supply one power supply for all load types allows galvanic conductive coupling via the conductors e Ifsolid state power supplies SSPS are used they can generate EMI on the input and output of the SSPS Rockwell Automation Publication MOTION ATOO4A EN P October 2011 16 Servo Drive Installation Best Practices To avoid noise related problems caused by 24V DC power supplies observe these guidelines Unless a floating supply is required bond the common output terminal to a ground terminal near the SSPS Avoid the use of long conductor lengths gt 150mm 5 9 in for this bond This bond provides an equipotential bond at high frequencies for all loads and normal machine wire appears as high impedance at high frequencies The longer the conductor the higher the impedance Use a ground terminal installed on the DIN rail fastened to a zinc plated panel to make the ground connection The use of clip on or snap on grounding terminals should be avoided Instead use clamp on style grounding terminals for a mechanical connection and additional bonding area When a common supply is part of the system design provide some isolation where needed using low pass DC filters Refer to Chapter 5 of the System D2. Table 1 through Table 4 provide advantages and disadvantages for each method illustrated beginning on page 19 Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 19 Figure 16 Cable Clamping Methods Table 1 Spring Clamp method A Advantages Disadvantages Very effective method Cost Easy to install snap or screw clamp onto DIN rail and insert cable section Plated material conductivity and oxidation benefits from dissimilar metals Sized to accommodate wide range of cable diameters Limited strain relief capabilities Provides good 360 bonding to exposed braided shield area Figure 17 Cable Clamping Methods continued Table 2 Heavy Duty Commercial Cable Clamp method B Advantages Disadvantages Very effective method Cost Each size covers a wide range of diameters Limited strain relief No additional drilling or tapping required Poor availability in some areas Rockwell Automation Publication MOTION ATOO4A EN P October 2011 20 Servo Drive Installation Best Practices Strapping your cable to a DIN rail the cable labeled C is crude but effective The DIN rail is raised off the panel slightly by using conductive washers to allow metal cable ties to pass underneath If spacing is desired care should be taken to use large outer diameter plated washers for the gap to maximize contact area Metal ties sho
3. clean zone of the next panel to the right e The divider panel is bonded with braided straps to the main panel at top center and bottom e Use 25 4 mm 1 0 in wide braided strap for bonding preferred method Braided strap 12 7 mm 0 5 in wide is acceptable Rockwell Automation Publication MOTION ATOO4A EN P October 2011 8 Servo Drive Installation Best Practices You can convert wiring designated dirty or very dirty to the next lower category by using either shielded cable or conduit where required These figures show how this technique can be used to mix categories without breaking the segregation rules Figure 4 Very Dirty Cable in Clean Zone Dirty Zone EMC Filter to Drive Cable Hi cee ha 24V DC1 0 mi Cable Very Dirty Zone Dirty Zone 7 Dirty Zone Very Dirty Zone one Motor Power Cable ti IVI l IVI Io i ln Minimum 150 mm 6 0 in Segregation Figure 5 Clean Cable in Very Dirty Zone ol Di7 d irty Zone Analog Device Cable I l i ra il eae i ea i a qT j 1 24D o j Z l l Cable i 7 4 Clean Zone Dirty Zone Very Dirty Dirty Zone Clean Zone Zone I l __ Encoder Cable I J i Minimum 150 mm 6 0 in alee The cable is locally shielded to cross another zone Each shield is grounded at each boundary and the cable is run close to the
4. AWG minimum stranded copper wire to connect each chassis enclosure and central ground bus mounted on the back panel Drive Motor Installations Make sure that drive grounding is properly connected as illustrated below The ground wire return between the motor and the drive must be terminated directly to the drive PE terminal Shielded cable is recommended but not always needed Refer to the product specific documentation for requirements Figure 10 Grounding the Drive and Motor Actuator Connection to Drive Structure or Optional Cabinet via Optional Enclosure P Conduit Connector Motor Frame AC Drive L Conduit R U S V Motor T w PE PE or Motor Frame P Saa Panel Ground Bus l Ground Ground Bus Connected Directly to Drive PE Terminal Making an adjustment to the servo drive to bleed off static charges when ungrounded or high impedance grounded power configurations exist can improve system performance This usually involves a jumper setting or similar action depending on the drive family Refer to your servo drive user manual for drive specific information Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 13 Kinetix 300 350 Drive Installations This figure shows an example of three phase power wires for motors actu
5. MOTION ATOO4A EN P October 2011 18 Servo Drive Installation Best Practices Enclosure Lighting Installations If you must use fluorescent lamps inside ofan enclosure observe these guidelines as shown in the figure e Install a shielding grid over the lamp e Use shielded cable between the lamp and its switch e Use a metal encased switch e Install a filter between the switch and the power line or shield the power line cable Figure 15 Fluorescent Lamps Wired Inside an Enclosure r 53 O e QO s o Filter AC Power aa aaa oe A Shielding grid Shielded Metal Encased Line Filter or Over Lamp Cable Switch Shielded Power Line Installing Cables Consider these cable shield clamping methods and guidelines for cable length excess cable ferrite sleeves and ferrite beads Clamping at the Circular Section For a modern control system comprised of a considerable amount of high frequency currents the only acceptable method for terminating most cable shields is with a circular or 360 clamping method This clamping method provides a balanced contact and conductivity for current flow around the circumference of the shield In addition a typical circular conductor exhibits higher than expected impedance at high frequencies Clamping at the circular section or 360 bonding as illustrated is the preferred method for grounding cable shields All of the clamping methods shown are acceptable
6. except registration Limit switches Push buttons Proximity switches except registration Photoelectric cell 24V DC relay Transformer indicator lamp Data communication shielded x X X X X X X Xx Encoder resolver shielded Logic circuit power shielded High speed registration inputs shielded PLC analog 1 0 PLC high speed counter input x x x x x x 1 An Xin this column indicates a ferrite sleeve fitted to the wire is recommended 2 An Xin this column indicates a shielded cable is recommended Rockwell Automation Publication MOTION ATOO4A EN P October 2011 x x x x x x Additional Resources These documents contain additional information concerning related products from Rockwell Automation Resource Description System Design for Control of Electrical Noise Reference Manual publication GMC RM001 Information examples and techniques designed to minimize system failures caused EMC Noise Management DVD publication GMC SP004 by electrical noise Wiring and Grounding Guidelines for Pulse Width Modulated PWM AC Drives Provides basic information needed to properly wire and ground pulse width publication DRIVES IN001 modulated PWM AC drives Provides general guidelines for installing an Allen Bradley industrial automation Industrial Automation Wiring and Grounding Guidelines publication 1770 4 1 system that may include programmable co
7. fasteners along the edges of the plate Scrape the paint or anodizing from around each fastener to maximize metal to metal contact Though not always applicable a plated cabinet frame is desirable since it makes a high frequency bond between the panel and cabinet sections more reliable For doors 2 m 78 in in height ground the door to the cabinet with two or three braided straps Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 11 Figure 8 Panel Ground Plane Extended to Adjacent Panels Adjacent panels wo bonded to extend the ground plane Sa Cabinet Ground Plane component mounting panel gt l l l I I I l l l i l I i I I ll P N p lt Ground plane extended to side panel a7 by bonding to main panel Figure 9 Bonded Ground Buses Connecting Multiple Subpanels Bonded Ground M i PT ooooog Ground Grid or Power Distribution Ground Always follow NEC and applicable local codes Rockwell Automation Publication MOTION AT004A EN P October 2011 12 Servo Drive Installation Best Practices in 5 gt Building Ground Potential w Installing System Components In addition to making good connections through each bolt or stud use either copper braid 25 4 mm 1 0 in wide or 8
8. impedance conductors routing to some distant ground terminal A plated cabinet frame is also highly desirable because it makes HF bonding between panel and cabinet sections more reliable e Painted metal panels must have the mating surfaces scoured free of paint and roughed at each mounting point of every piece of metal clad equipment and the exposed surfaces protected against corrosion with conductive paint or petroleum jelly The disadvantage with painted panels apart from the labor cost to remove paint and re coat the areas with a conductive coating is the difficulty of making quality control checks to verify that paint was properly removed Without a conductive re coating future corrosion of the unprotected mild steel will compromise the already reduced bonding performance e Anodized aluminum panels must have the mating surfaces cleaned of anodizing and the exposed surfaces protected against corrosion This type of back panel material should also be avoided when mounting solid state components because aluminum does not provide magnetic shielding benefits e Stainless steel panels are acceptable but are inferior to conductive plated mild steel due to their higher resistance Most versions or families of stainless steel have poor magnetic properties thus eliminating some of the shielding benefits that sheet steel offers In summary do not consider painted steel aluminum anodized aluminum and stainless steel panels and enclosure
9. p Bett acnvrr ojo C 3 48 8 18 Sie E o le avoe O O NUT O18 ANGER 5 S IS ee T S glo lo O l S 3 8 ZA Lf E 3 7 2 5 4 1 To Motor Item Description Item Description 1 24V power supply 5 1 0 10D connector 2 Relay and diode assembly 6 2097 V3xPRx xx Kinetix 300 350 drive 3 Minimize unshielded wires in brake circuit 7 Motor power MP connector 4 MP Series cable brake wires 8 Cable clamp Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 15 Kinetix 6000 and Kinetix 6200 6500 Drive Installations e Attach the braided grounding strap from the grounding stud on the power rail to the bonded cabinet ground e When installing mounting brackets with either the Kinetix 6000 power rail or the LIM module attach the braided grounding strap as illustrated in the figure below Figure 13 Power Rail Grounding Braided 2094 Power Rail Ground Strap Bonded Cabinet x Ground Bus Line Interface Module on PKH Ground Grid or Power Y Bulletin 2094 Mounting Brackets Distribution Ground aa 2094 XNBRKT 1 2094 Mounting Bracket w 2094 Mounting Bracket 2094 Power Rail on E 2094 XNBRKT 1 Bulletin 2094 Ground Stud Mounting Brackets 2 3S Bonded Cabinet Ko Ground Bus Braided Ground Strap o a i Ground Grid or Power Distribution Ground Ground Stud a Bonded Cabinet
10. Application Technique Servo Drive Installation Best Practices Introduction Allen Bradley Topic Page Introduction 1 Installation Checklist 3 Planning the Installation 4 Panel Material 4 Establishing Noise Zones 5 During the Installation 9 High Frequency Bonding 9 Installing System Components 12 Installing Cables 18 Suppressing Contact Switched Loads 25 Leakage Current Considerations 28 Isolation Transformers 28 Component and Wiring Noise Zone Classifications 30 Additional Resources 32 Use this publication as a quick reference guide of installation best practices for Rockwell Automation single axis and multi axis servo drive systems These practices also apply to most variable frequency VFD drives adjustable speed ASD drives and other control components with solid state power supplies SSPS Use these best practice examples to help reduce the number of potential noise or electromagnetic interference EMI sources in your system and make sure that the noise sensitive components are not affected by the remaining noise EMI mitigation or management is a process that involves reducing and managing the cause and magnitude of EMI and then combining these reduced levels with proper routing of generating and receiving conductors and components Rockwell Allen Bradley Rockwell Software Automation 2 Servo Drive Installation Best Practices While reading this reference guide k
11. Lengths Although motor power and feedback cables are available in standard lengths up to 90 m 295 3 ft the drive motor feedback combination may limit the maximum feedback cable length Combined motor power cable length for all axes on the same DC bus is also subject to drive specific limitations Refer to your servo drive user manual for more information Minimizing Loops Wires that form a loop make an efficient antenna Run feed and return wires together rather than allowing a loop to form Twisting the pair further reduces the antennae effects and can significantly reduce EMI Figure 22 Avoiding Loops in Wiring Designs Switch X Switch Switch Not Recommended Good Solution Better Solution TIP This applies to victim wiring too Antennae work equally well in receive and transmit modes The twisting of the signal pair reduces the magnetic field pickup area and helps to make sure that both conductors in the pair couple have the same level of EMI As a result the EMI is rejected by the differential op amp receiver Rockwell Automation Publication MOTION AT004A EN P October 2011 24 Servo Drive Installation Best Practices Excess Cable Observe these guidelines when handling excess cable e Do not coil excess cable of different types for example motor power and feedback together An efficient transformer is formed at HF e Cable lengths should ideally be trimmed to fit the application e I
12. at conduct the stray current which originated in the attached drive back to the output phase conductors and into the originating drive This means that the stray currents return back to the source Therefore it is important to have the filter chassis at the same potential as the drive ground terminals DIN rail terminals and cable shield clamps Treat wiring between filter and drive as very dirty provide shielding as required e Segregate input and output wiring as far as possible Do not route the two sets of conductors parallel to each other in the same wire duct This allows cross coupling of the dirty filter output to the clean filter input conductors thus defeating the purpose of the filter Figure 14 Positioning Line Filter and Servo Drive Dirty Wireway ioe A Motor Power Cables Very Dirty Filter Drive Connections Motor Power Cables Very Dirty Filter Drive Connections Segregated not in wireway Segregated not in wireway Very Dirty Zone Al all bs VAC Load A a i i i E i VAC Line v dme oO Very Dirty Zone VAC Load AC Line Filter VAC Line Dirty Wireway Kinetix 6000 Drive System Kinetix 6000 Drive System line filter mounted behind drive system line filter mounted left of drive system Rockwell Automation Publication
13. ators that do not require brake wires Thermal switch wires are included in the feedback cable Figure 11 Motor Power Terminations three phase wires only lt gt Motor Power Ground Oe Shield Clamp nee ee 1 0 e e he 34 0 e L127 1 34 0 50 Dimensions are in mm in 50 75 2 3 If panel is painted remove paint to we provide metal to metal contact Rockwell Automation Publication MOTION ATOO4A EN P October 2011 14 Servo Drive Installation Best Practices This figure shows an example of wiring with three phase power and brake wires The brake wires have a shield braid shown as gray that folds back under the cable clamp before the conductors are attached to the motor brake circuit Thermal switch wires are included in the feedback cable Figure 12 Motor Power Terminations three phase and brake wires 3 E Bea eu A Kinetix 300 Oe l OI wenane rom ie 3 o Sa em olol 4
14. d dirty zones TIP It is preferable to mount the PLC and motion control equipment in a separate cabinet away from the power control equipment motor starters for example Additional isolation can be obtained by employing a simple slotted or perforated sheet metal barrier between wire ducts Maintain good contact with the plated back panel surface to make sure the L barrier has equipotential with the back panel Be careful to keep slots and holes to a minimum to avoid radiating EMI through the material voids based on frequency and wave length Rockwell Automation Publication MOTION ATOO4A EN P October 2011 6 Servo Drive Installation Best Practices Routing Cables These figures provide examples of how to route clean dirty and very dirty wireways or cable trays within a panel Refer to Component and Wiring Noise Zone Classifications on page 30 Figure 2 Routing Clean and Dirty Cables Main Panel front view Power Distribution Dirty Zone black wireway Barrier Sensitive Equipment Clean Zone gray wireway Relays Observe these guidelines when planning your panel layout for clean and dirty cables e The plated steel barrier between clean and dirty wireways allows them to run close together e Ifdirty power is required at A then run it via wireway B using shielded cable e The vertical wireway at C is not good practice as it encourages the creation
15. ected dangerous currents voltages present on the equipment chassis to earth ground Due to the points mentioned above ground conductors provide a lower resistance to ground than body parts however they do not typically make good low impedance paths to the equipotential plane at HF Failure to create low impedance paths from component to component can result in an offset or potential difference and voltage This document is not intended to replace any existing documentation including but not limited to product user manuals installation instructions and the System Design for Control of Electrical Noise Reference Manual publication GMC RM001 Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 3 Section Panel Material Installation Checklist Technique Whenever possible use galvanized or plated panels For painted panels remove paint from mating surfaces Establishing Noise Zones Noise zones established clean dirty components and cables segregated High Frequency Bonding Panels ground buses control components and machine structure properly bonded Grounding the Drive Drive chassis and power rail if applicable properly grounded Installing 24V Power Supplies 24V power supply properly grounded and decoupled at clean loads Installing EMC Line Filters EMC line filter installed as close to drive as possible Installing Enclosure Lighti
16. eep in mind the following key points that tend to be misunderstood EMI is present in all control systems and can affect expected signal integrity which can in turn cause circuits to energize or de energize inputs and loads stopping production and causing equipment failure The frequency range of primary concern is 100 kHz to 10 MHz which in this document is referred to as high frequency or HF The physics property skin depth or skin effect refers to the outer circumferential depth of a conductor from OD towards center through which AC current can flow As the frequency increases the skin depth decreases In addition as the diameter of the conductor decreases or the conductor length increases the reflected impedance increases Consequently it is important to avoid the use of long or high gauge small diameter conductors for HF bonding purposes Typical control wiring or conductors green insulated ground wires reflect much higher impedance resistance at HF than is typically expected due to inductive reactance The frequency effect is often forgotten and the digital multi meter resistance measurement of 0 1 or 1 ohm is based on the power frequency 50 and 60 Hz and not at the HF range 100 kHz to 10 MHz Bonding conductors or components are not the same as ground conductors or wires The bond conductor s purpose is to create an equipotential level at HF for a control system and the ground conductor s purpose is to route unexp
17. er Figure 29 Transient Absorber RND Good Solution Common Transient Absorber 24V DC Better Solution Common ye Transient Absorber Rockwell Automation Publication MOTION ATOO4A EN P October 2011 28 Servo Drive Installation Best Practices Leakage Current Considerations Leakage current is inevitable in servo drive systems due to the capacitive components within the drives Another source for leakage current is the cabling in the system which induces capacitance in the system As cable lengths increase so does leakage current In addition the leakage current increases with unbalanced loads from the mains phases and when the number of drives increases in a system Finally line filters drastically increase the leakage current in the system This presents a particular challenge in designing a system to reduce noise and leakage current Ifa filter must be used for EMC purposes but European Conformity CE is not required consider applying a low leakage current filter to reduce overall leakage current If using an Earth Leakage Circuit Breaker ELCB consider reducing the sensitivity to minimize nuisance trips In some cases a harmonic filter to filter noise in conjunction with a circuit breaker set at 60 Hz to protect personnel can replace the ELCB IMPORTANT Reduce cable lengths as much as possible to minimize capacitive loading along cables Isolation Tra
18. esign for Control of Electrical Noise Reference Manual publication GMC RMO001 for more information An option for suppressing the related noise is to decouple the 24V DC line to the same ground terminal with a 1 uF 50V ceramic capacitor to achieve the clean category Single phase Power Supply Installations To avoid noise related problems caused by single phase power supplies observe these guidelines Treat single phase wiring as dirty Include line filters for loads that create noise such as PWM devices with DC switch mode power supplies and fluorescent cabinet lights Include line filters for potentially sensitive loads such as PLC logic power Mount the line filter as close to the load as possible Rockwell Automation Publication MOTION ATO04A EN P October 2011 Servo Drive Installation Best Practices 17 EMC Line Filter Installations To meet CE requirements include line filters for loads that create noise such as drives and other PWM loads with three phase power supplies Observe these guidelines when installing line filters e Install the line filter as close to each drive as possible preferably next to the drive input connector Position the filter output terminals as close to the drive input terminals as possible refer to Figure 14 for example e Install the filter and drive on the same panel to provide the same equipotential surface to each The filter chassis has internal high frequency capacitors th
19. fexcess cable cannot be trimmed it should be laid in an S or figure eight pattern refer to the figure below Figure 23 Excess Cable Treatment Poor Method X Ferrite Sleeves Shielded data cables grounded at both ends important at high frequencies may carry noise current due to voltage differences between the two ends Because the shields have a low impedance currents may be quite high even though voltage is low By installing ferrite sleeves the common mode impedance of the cable is greatly increased at high frequencies thus blocking the noise currents without affecting the signal currents In this figure capacitor grounding is very effective and avoids no grounding rules but can be awkward to implement Figure 24 Ferrite Sleeves Increase Common Mode Impedance Ferrite sleeve greatly increases impedance at RF Optional Capacitor Panel A Panel B Differential Noise Voltage Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 25 Observe these implementation guidelines for ferrite sleeves e Always install ferrite sleeves to data cables where specified e Always use ferrite sleeves when cable length is greater than 10 m 30 ft If power frequency ground currents are expected or measured by current clamp one shield ground connection could be made via a 1uF 50V capacitor Ferrite Beads Ferrite beads provide additional suppressi
20. must be suppressed x x x x x x x x Rockwell Automation Publication MOTION AT004A EN P October 2011 An X in multiple zones indicates that the component straddles the two zones Under these circumstances it is important to position the component in the correct orientation An Xin this column indicates a ferrite sleeve fitted to the wire is recommended An Xin this column indicates a shielded cable is recommended The connector terminal block locations on the drive will normally dictate the zone geometry since it normally has connections in all categories Design zones around the drives Servo Drive Installation Best Practices 31 Wiring Noise Zone Description Three phase between sine filter and drive shielded Table 6 Wiring Noise Zone Categories Zone Method Very Dirty Dirty Clean Suppress Ferrite Shielded 2 Sleeve Cable X Extended DC bus shielded X PWM drive inverter to motor power shielded PWM drive inverter to sine wave filter Sine wave filter to motor CM choke to motor power shielded Line terminator to motor power shielded External dump shunt resistor shielded Contactor to AC motor shielded Three phase power supply x x x x Single phase power supply 24V hydraulic pneumatic to solenoids Motor feedback resolver shielded xj x x x x x x x PLC digital 1 0 Dedicated drive inputs
21. ng Fluorescent lamps properly installed so as to suppress EMI Installing Cables cable lengths minimized and wire loops avoided Cables shielded where appropriate with 360 termination methods employed and grounded at both ends Suppressing Contact Switched Loads Contact switched loads suppressed Isolation Transformers 1 Use this technique only if designing to reduce leakage current rather than to minimize noise EMC line filter is required to meet CE approval Isolation transformer used in place of EMC line filter 1 Rockwell Automation Publication MOTION ATOO4A EN P October 2011 4 Servo Drive Installation Best Practices Planning the Installation When planning your servo drive panel installation consider the panel material and how you plan to lay out the system components Panel Material High frequency HF bonding of the servo drive system components with the 8 q y 8 y P panel they are mounted on is essential to minimizing electrical noise e Conductive plated steel panels are strongly recommended due to the inherent ability of the material to resist corrosion and to bond with the drive chassis bonding components for example shield clamps programmable logic controllers and solid state power supplies SSPS In addition a steel cabinet provides good magnetic shielding properties and provides equipotential bond ground points anywhere on the panel This eliminates the need for long high
22. ng adhesive copper tape Use foil that offers the best coverage and electromagnetic shielding of the cables Wrap the tape around the exposed braid area This avoids having to bend and possibly break the individual strands by the clamp or wire tie Figure 19 Cable Clamping Methods adhesive copper tape and wire tie Cable Shield Terminations Proper cable shield termination is affected by where the shield is terminated In the past attempts to bond the cable shield at both ends sometimes caused low frequency currents to flow through the shield causing a hum or disturbance to the inner conductor signal referred to as a ground loop As a result single end cable shield termination or in some cases the avoidance of using shielded cable is common practice Single ended shield termination causes the cable to act as a high frequency antenna and consequently is susceptible to high frequency pickup For this reason avoid using the single ended termination method With modern high frequency control systems there are noticeable benefits to properly terminating the cable shield at both ends of the cable using 360 termination techniques e Fora motor power cable terminating at both ends often provides the lowest impedance path for stray capacitive coupled currents to return back to the drive chassis source Using proper 360 terminations further reduces this impedance e The common mode voltage across the self inductance of the shield gene
23. nsformers If European Conformity CE is not a requirement consider installing a system isolation transformer rather than an EMC line filter to isolate noise within the system Transformers must be sized at double the sum of the output power of each axis An isolation transformer is frequently assumed to give good noise isolation In fact this applies only if the transformer is equipped with one or more electrostatic ES shields as illustrated in the figure below Figure 30 Electrostatically Shielded Transformer Primary Secondary l ie Frame Bonded to Ground Plane Shields Bonded to Ground Plane Ground Plane Rockwell Automation Publication MOTION ATO04A EN P October 2011 Servo Drive Installation Best Practices 29 This technique is very effective though EMC filters are required to meet European regulation standards Observe these guidelines when installing transformers e Install the transformer to the same panel as the rest of your system or HF bond from panel to panel e Treat wiring between transformer and drive as very dirty when no EMC filter is present provide shielding as required e Bond shield if used with braid directly to the panel The transformer mounting bolts are useful for this e Segregate input and output wiring as far as possible When using an isolation transformer attach a chassis ground wire to the neutral connection This grounded neutral connection does the following e Pre
24. ntrollers industrial computers operator interface terminals display devices and communication networks You can view or download publications at http www rockwellautomation com literature To order paper copies of technical documentation contact your local Allen Bradley distributor or Rockwell Automation sales representative Allen Bradley Kinetix MP Series Rockwell Software and Rockwell Automation are trademarks of Rockwell Automation Inc Trademarks not belonging to Rockwell Automation are property of their respective companies www rockwellautomation com Power Control and Information Solutions Headquarters Americas Rockwell Automation 1201 South Second Street Milwaukee WI 53204 2496 USA Tel 1 414 382 2000 Fax 1 414 382 4444 Europe Middle East Africa Rockwell Automation NV Pegasus Park De Kleetlaan 12a 1831 Diegem Belgium Tel 32 2 663 0600 Fax 32 2 663 0640 Asia Pacific Rockwell Automation Level 14 Core F Cyberport 3 100 Cyberport Road Hong Kong Tel 852 2887 4788 Fax 852 2508 1846 Publication MOTION ATOO4A EN P October 2011 Copyright 2011 Rockwell Automation Inc All rights reserved Printed in the U S A
25. of loops refer to Minimizing Loops on page 23 e The use of different colored wireways for example gray for clean and black for dirty encourages good segregation When strict segregation is not practical make sure that the cables cross at right angles to minimize noise transfer Rockwell Automation Publication MOTION ATO04A EN P October 2011 Servo Drive Installation Best Practices 7 Figure 3 Routing Very Dirty Cables Main Panel Right Side Panel front view inside view XXX Segregation fro a Clean Dirty Zone BS lt Zinc Plated Cable Tray Dirty Zone black wireway T ii Drive Power Connections forming bridge to cable tray XX AKKKK KKK AKKAKAK XXX Very Dirty Zone white cable tray Clean Zone gray wireway Divider Panel Clean and Dirty Zone Wireways KKAKKKAKKKAKAAAKA XK KA KKKAKKKAKKKARKKKKA X bsos IXXXXXXXOL JVOO Cable Tray Bonded with Braided Strap to Main Divider Panel Divider Panel Bonded with Braided Strap to Main Panel three places Observe these guidelines when planning your panel layout for very dirty cables e Power cables bridge across to the drive terminals from the cable tray on the right e The cable tray is bonded to the divider panel with braided strap If no divider panel is used then bond the cable tray to the main panel e A divider panel is used on the right to segregate very dirty wiring from the
26. on of transient noise and are available for category 2 and 3 conductors You can secure them with heat shrink tubing or tie wraps With a ferrite bead located near the end of a cable or cable segment in the case of a daisy chain or dropline configuration transient noise induced onto the cable can be suppressed by the bead before it enters the equipment connected to the end of the cable Suppressing Contact Switched Loads Contact suppressors for solenoids relays and various other switches can directly reduce electrical noise AC Circuits Examples of AC devices requiring contact suppression include the following e Line filters often present an inductive load e Contactor controlled motors e Solenoid coils e Conductor coils e Relay coils e Transformer primaries e Transformer driven indicator lamps e Fluorescent cabinet lights also require line filters close to the lamp A commonly overlooked point of suppression are the contacts of the relays or contactors for single and three phase loads specifically contacts that can be cycled during machine operation Contactors that are energized when the machine is powered up may generate EMI which could be missed by signals or circuits which are not yet active Other contacts should be suppressed with the appropriate single or three phase RC network Rockwell Automation Publication MOTION ATOO4A EN P October 2011 26 Servo Drive Installation Best Practices This typical RC supp
27. or effect and the loss of conductive contact at the bond point Shielding Cables This figure illustrates how to properly prepare the power cable shield braid for a 360 cable clamp Figure 20 Power Cable Shield and Lead Preparation Strip Length gt lt U V Outer Insulation Motor Power Cable lf Exposed Braid 25 4 mm 1 0 in lt As required to have ground clamp within gt gt 50 75 mm 2 3 in of the drive This figure illustrates how to properly clamp the flying lead feedback cable shield braid and make wiring connections in a connector kit Figure 21 Feedback Cable Shield and Lead Preparation Foil Shield Bulletin 2090 Feedback Cable im a Low Profile Connector Kit 2090 K2CK D15M al Ea si Clamp j a TN im IE a ie Exposed Braid Under Clamp 015141312 11109 87 6 5 4 3 21 aie ran aaron qi kc 3 Turn clamp over to hold DNY Tie Wrap small wires secure Bulletin 2090 Feedback Cable Rockwell Automation Publication MOTION AT004A EN P October 2011 Servo Drive Installation Best Practices 23 Cable
28. panel The outer shield A is thick walled steel conduit Rockwell Automation Publication MOTION ATO04A EN P October 2011 Servo Drive Installation Best Practices 9 During the Installation During the installation of your servo drive and motor actuator system make sure you observe these noise reducing techniques for high frequency bonding installing system components installing cables and suppressing contact switched loads High Frequency Bonding The purpose of high frequency bonding is to present a defined low impedance path for HF noise currents returning to their source When using a painted panel mating surfaces must be scoured free of paint at each mounting point of every piece of metal clad equipment Exposed surfaces must be protected against corrosion with conductive paint or petroleum jelly The following figure illustrates the recommended bonding practices for painted panels Figure 6 Recommended Bonding Practices for Painted Panels Stud mounting the Subpanel Stud mounting a Ground Bus to the Enclosure Back Wall or Chassis to the Subpanel Subpanel Back Wall of Mounting Bracket or Enclosure Ground Bus Subpanel Welded Stud Star Washer Flat Washer Scrape Paint Welded Stud Flat Washer Use a wire brush to remove paint from Paes If the mounting bracket is coated with threads to maximize ground connection Y a non conductive material anodized or painted scrape the material around Use plated panels or
29. rates a canceling voltage to the EMI in the conductors inside the shield when it is bonded at both ends When the cable shield is properly managed the high frequency currents usually have little effect on modern digital circuits However if the low frequency currents appear to cause disturbances on a cable using dual ended 360 terminations then a hybrid termination can be achieved by replacing the machine end termination with a conductive band and 1 0 uF capacitor installed from the band to chassis there are products manufactured for this purpose The capacitor blocks low frequency currents from circulating through the shield and shorts the high frequency currents to the shield Rockwell Automation Publication MOTION ATOO4A EN P October 2011 22 Servo Drive Installation Best Practices Ji R Braided Shield Outer Insulation gt A common mistake when terminating a cable shield is using the drain conductor to create a pigtail by twisting the braid together and inserting a portion of it into a convenient inexpensive terminal This technique should not be used as it generates a large loss through potential attenuation or reduction in EMI on the inner signal conductors of the cable The benefits of the cable shield are reduced as a result of the following e The non uniform distribution of shield current around the circumference of the shield e The added impedance at high frequencies created by using a conduct
30. ressor circuit consists of a 0 1 F capacitor in series with a 100 Qresistor Figure 25 RC Suppressor Circuit Ha 0 1 uF 10 Q This typical RC plus transient absorber circuit consists of the RC network shown in the figure above in parallel with a transient absorber These are used in high current high energy applications such as motor starters A three phase contactor requires three suppressors Figure 26 RC Plus Transient Absorber Circuit Transient Absorber 0 1 uF 10 Q This suppressor across the contact reduces the noise from the wiring inductance as well as the coil inductance Figure 27 RC Suppressor in Circuit Good Solution 3 Line m P c RC Suppressor ean ee Better Solution Rockwell Automation Publication MOTION ATO04A EN P October 2011 Servo Drive Installation Best Practices 27 24V DC Circuits Examples of DC devices requiring contact suppression include the following Solenoid coils e Contactor coils e Relay coils The first choice for DC circuit suppression is a flywheel diode but this increases the release time that may not be acceptable in all applications Figure 28 Flywheel Diode 24V DC Good Solution Common Flywheel Diode 24V DC Better Solution C Common X Flywheel Diode The second choice for DC circuit suppression is a transient absorb
31. s If these materials are used additional steps should be taken to minimize EMI Rockwell Automation Publication MOTION ATO04A EN P October 2011 Main Panel or Cabinet top view Servo Drive Installation Best Practices 5 Establishing Noise Zones You can greatly reduce noise by segregating components and wiring in zones according to their EMI levels and noise susceptibility A good practice to consider is the application of colored wireways to provide the installer with a constant reminder of where the different classes of conductors can be routed safely Refer to Component and Wiring Noise Zone Classifications on page 30 Segregating Components This figure shows how you can create three zones in a standard panel or cabinet enclosure The very dirty items are placed in the right front section The dirty items are placed behind them in the right rear section and the least noisy clean items are placed in the left rear section Figure 1 Relative Position of Noise Zones on the Panel Clean Wireway and Component Mounting Section Dirty Wireway and Component Mounting Section Right Side lt 4 Left Side and Front Panels if cabinet Divider Panel multi bay cabinets Very dirty Cable Tray and Component Mounting Section A side panel is fitted on the right to support the power cable shield clamps and any very dirty wires cables or components This leaves the main panel free for the clean an
32. scrape paint on Star Washer the mounting hole front of panel Bolt mounting a Ground Bus or Chassis to the Back panel Subpanel Tapped Hole Ground Bus or Mounting Bracket K S BOX Star Washer Scrape paint on both sides of N panel and use star washers Star Washer Flat Washer If the mounting bracket is coated with a non conductive material anodized Star Washer or painted scrape the material around the mounting hole Rockwell Automation Publication MOTION ATOO4A EN P October 2011 10 Servo Drive Installation Best Practices Figure 7 Ground Bus Example Ground Bus Mounting Ground Bus Equipment Grounding Conductors Tapped Hole BS _ Ground Lug olt ay T Grounding electrode conductor to grounding electrode system Star Washer Bonding multiple subpanels creates a common low impedance exit path for the high frequency energy inside the cabinet Subpanels that are not bonded together may not share a common low impedance path This difference in impedance may affect networks and other devices that span multiple panels Observe these guidelines when bonding multiple subpanels Bond the top middle and bottom of each subpanel to the cabinet by using 25 4 mm 1 0 in by 6 35 mm 0 25 in wire braid As a rule the wider and shorter the braid is the better the bond Panel bonding is illustrated in the following figure As an alternative mount a filler plate between the panels using multiple
33. uld be thin enough to avoid the spacing washers The use of non conductive ties will not provide adequate balanced conductivity around the circumference of the cable shield Table 3 Strapping to DIN Rail method C Advantages Disadvantages Very effective method Each size covers a wide range of diameters Appearance Moderate strain relief Low cost Plain copper saddle clamps the cable labeled D are sold for plumbing purposes but are very effective and available in a range of sizes Table 4 Saddle Clamp method D Advantages Disadvantages Very effective method Requires two drilled and tapped holes per cable Available in a wide range of sizes Excellent strain relief Each size will accommodate a limited range of diameters Low cost Additionally you can install and mount flat copper or galvanized plated tabs to the plated back panel Use these tabs with metal cable ties or small hose clamps to form a simple 360 cable shield termination with good strain relief This method is easy to install and made from ordinary shop materials Figure 18 Cable Clamping Methods plated tabs and hose clamp Steel Tab with Turned up End to Hold Clamp in Place Exposed Shield Braid Covered with Copper Tape Basic Hose Clamp Rockwell Automation Publication MOTION ATO04A EN P October 2011 Servo Drive Installation Best Practices 21 You can protect the small strands of a braided cable shield by usi
34. vents the system from floating and thereby avoids any high voltages that might otherwise occur for example due to static electricity e Provides a solid earth path for fault conditions ATTENTION If the supply transformer is an auto transformer not recommended a chassis earth ground should not be added A chassis earth ground should already be included elsewhere in the system and adding another would create a short Rockwell Automation Publication MOTION ATOO4A EN P October 2011 30 Servo Drive Installation Best Practices Component and Wiring Noise Zone Classifications Component Noise Zone Description PWM drives amplifiers 4 These tables indicate the zoning requirements of cables connecting to the drive components Table 5 Component Noise Zone Categories Zone Method Very Dirty Dirty Clean Suppress Ferrite 2 Sleeve Shielded Cable Dynamic braking components External dump resistor shielded EMC line filter Dump resistor module metal clad Switch mode DC power supply Ultrasonic transducer x x x x Contactors MCB Switched 24V DC loads for example E stop Piltz circuit solenoids relays Encoder buffer board PLC Registration 24V DC power supply filter Dirty to clean filter Linear DC power supply Other 24V DC non switched loads Data communication devices Analog devices All inductive switched loads
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