Integrated Motion On EtherNet/IP: Maximizing Network Performance

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This presentation is focused at helping designers of EtherNet/IP based motion systems to understand the fundamental principles behind the core technology (CIP Motion) and its relationship to time. Discover how the use of time in the architecture allows for determinism and provides a platform for high performance control. Gain insight into infrastructure selection, network arrangement and how devices with CIP Sync technology can also be applied to a high performance, deterministic control solution.

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Integrated Motion On EtherNet/IP: Maximizing Network Performance

  1. 1. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. PUBLIC INFORMATION AD19 - Integrated Motion On EtherNet/IP: Maximizing Machine Performance
  2. 2. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved.  This session is focused at helping designers of EtherNet/IP based motion systems to:  Understand the fundamental principles behind the core technology (CIP Motion) and its relationship to time  Discover how the use of time in the architecture allows for determinism and provides a platform for high performance control  Gain insight into infrastructure selection, network arrangement and how devices with ‘CIP Sync’ technology can also be applied to a high performance, deterministic control solution Session Description
  3. 3. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Keeping it all in perspective 3 This presentation focuses on the fundamentals of CIP Motion and CIP Sync technologies and the relationship of time and position in the system. It correlates these basic parameters of a CIP Motion architecture against the network infrastructure and helps the designer to understand how to apply best practices for an infrastructure which communicates the proper timing and positioning information in these systems. However given this, the variations introduced by networking infrastructure are measured in nanoseconds and microseconds. Fluctuations introduced by the network are usually negligible compared to other boundaries in the system: Compliance and backlash Mechanical system time constants System Tuning
  4. 4. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. EtherNet/IP - Enabling/Driving Convergence of Control and Information 4 Industrial Network Convergence Converged Plantwide EtherNet/IP Industrial Network Model Corporate Network Sensors and other Input/Output Devices Motors, Drives Actuators Supervisory Control Robotics Back-Office Mainframes and Servers (ERP, MES, etc.) Office Applications, Internetworking, Data Servers, Storage Human Machine Interface (HMI) Safety Controller Traditional – 3 Tier Industrial Network Model Corporate Network Sensors and other Input/Output Devices Controller Motors, Drives Actuators Robotics Back-Office Mainframes and Servers (ERP, MES, etc.) Office Applications, Internetworking, Data Servers, Storage Control Network Gateway Human Machine Interface (HMI) Supervisory Control Camera Phone Industrial NetworkIndustrial Networks Safety I/O I/O Controller
  5. 5. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved.  CIP Motion coordinates devices in a manner that’s similar to our own methods for coordinating meetings and events  All members (devices) have clocks to compare time to an absolute base and scale  A destination (position) is targeted for the event  A time (timestamp) is set for when the event shall occur  A message is sent to each member (device) to meet at the given place at the pre-determined time  Not all messages might arrive at precisely the same time! Birthday Party! Cafeteria 12:00 pm Fundamental Principal of CIP Motion Control
  6. 6. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Cafeteria  CIP Motion coordinates devices in a manner that’s similar to our own methods for coordinating meetings and events  All members (devices) have clocks to compare time to an absolute base and scale  A destination (position) is targeted for the event  A time (timestamp) is set for when the event shall occur  A message is sent to each member (device) to meet at the given place at the pre-determined time  Not all messages might arrive at precisely the same time!  But all members arrive in the proper position at the proper time for the event to take place! Fundamental Principal of CIP Motion Control
  7. 7. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Motion Task Target Time = Tctr0 + 2*CUP Tctr0 Servo Update Period Course Update Period (CUP) Delivering Command Position with Time Stamp allows Drive to Compute a Trajectory to hit the Command Position at the Target Time. Tctr1 Tctr2 Drive Task Fine Interpolation Polynomial Target Time Target Command Position Last Target Time Last Command Position Motion Task Drive Task Controller Drive Axis Rotation Command Position Targeting Using Time Stamp KPI-1 = Tracking Error = Command Position (N-2) – Actual Position (N)
  8. 8. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. How is time synchronized in the system? Precision Time Protocol (PTP) Overview  Creates a master/slave hierarchy of clocks in the network  Best Master selection  Grandmaster transmits accuracy properties with Announce msg  Slaves pick best master  Synchronization timing messages  Between master and slave  Frequency Synchronization  Sync, Followup Msgs  Phase / Delay Measurements  Slave to Master  Delay_Req, Delay_Resp Msgs Master Clock Slave Clock TS TS Delay = (D1 + D2) / 2 time TS TS TS TS TS Time Stamp D1 D2
  9. 9. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved.  If clocks are off, members don’t know that their clocks are different from others against which they are coordinating  All members (devices) continue to compare time to an absolute base and time scale  A destination (position) is targeted for the event  A time (timestamp) is set for when the event shall occur  A message is sent to each member (device) to meet at the given place at the pre-determined time Birthday Party! Cafeteria 12:00 pm What happens if the clocks are off?
  10. 10. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Cafeteria  If clocks are off, members don’t know that their clocks are different from others against which they are coordinating  All members (devices) continue to compare time to an absolute base and time scale.  A destination (position) is targeted for the event  A time (timestamp) is set for when the event shall occur  A message is sent to each member (device) to meet at the given place at the pre-determined time  Members will arrive at the right place….  But at the wrong time….  ….this results in positioning error… Positioning Error 12:00 12:00 11:50 11:50 What happens if the clocks are off?
  11. 11. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. 11 Reference Axis Clock = 3:00 Follower Axis Clock thinks it’s 3:00 Time Position Position Error What happens if the clocks are off? KPI-2 = Registration Position Skew
  12. 12. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. How would clocks become offset?  Network infrastructure is a potential filter to the distribution of time in a system.  Although time is metered precisely from the master clock… …it may not be precisely delivered through the infrastructure distribution depending on traffic loading and infrastructure configuration… 3:01 3:02 3:03 3:04 3:05 3:06 3:07 3:08 3:01 3:02 3:03 3:04 3:05 3:06 3:07 3:08 KPI-3 = Registration Time Skew
  13. 13. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. How would clocks become offset? 13 M S Introduction of random, large volumes of data in a non-prioritized manner Introduction of large packet sizes 1500 bytes @ 100MBits/sec = 120 usecs Non-PTP Enabled Switch
  14. 14. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved.  Device Clock Filtering  Not user configurable  Topological Arrangement  Time Re-phasing Mechanisms  Boundary Clock  Transparent Clock  Traffic Prioritization  QoS – Quality of Service  DSCP - Differentiated Services Code Point  CIP Prioritization (ODVA Specification)  IGMP Snooping  Management of Multi-Cast Traffic 14 Typically Managed Switch Other Mechanisms How do I protect time in the system?
  15. 15. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved.  Advantages:  Ability to segment network (minimize network latency and jitter)  Network diagnostics and security features  Some provide security protocols  Some run loop prevention protocols  Some deliver Quality of Service (QoS)  Some multicast management (IGMP)  Some support precision time protocol (PTP)  Disadvantages:  Higher initial cost than an unmanaged switch  Some technical knowledge needed for setup Managed Switches 15
  16. 16. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Does this mean I can’t use an unmanaged switch? 16  No! You can use an unmanaged switch as long as you understand some key principles….
  17. 17. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved.  Advantages:  Simplified design and deployment  Ideal for small, isolated networks  Lower initial investment than a managed switch  Disadvantages:  No diagnostics  No security  No loop prevention  No QoS or prioritization of some traffic at the expense of other traffic  No PTP or adjustment to time stamp after passing packet  No IGMP Snooping capability for multicast traffic management Unmanaged Switches 17
  18. 18. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Using Multiple Unmanaged Switches in a Large System… 18
  19. 19. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Multiple Unmanaged Switches in a Large System Jitter at 0% Network Loading… 19 With no network load, there was little difference between test cases 0 500 1000 1500 2000 2500 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) "Golden" Axis (Connected directly w/o switch 0 200 400 600 800 1000 1200 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 1 0 200 400 600 800 1000 1200 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 2 0 200 400 600 800 1000 1200 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 3
  20. 20. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Multiple Unmanaged Switches in a Large System Jitter at 40% Network Loading… 20 0 200 400 600 800 1000 1200 1400 1600 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) "Golden" Axis (Connected directly w/o switch 0 50 100 150 200 250 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 1 0 20 40 60 80 100 120 140 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 2 0 10 20 30 40 50 60 70 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 3
  21. 21. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Multiple Unmanaged Switches in a Large System Jitter at 80% Network Loading… 21 0 500 1000 1500 2000 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) "Golden" Axis (Connected directly w/o switch 0 50 100 150 200 250 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 1 0 20 40 60 80 100 120 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 2 0 10 20 30 40 50 60 70 80 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 3
  22. 22. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Same Test Using PTP Managed Switch Jitter at 80% Network Loading… 22 0 5000 10000 15000 20000 25000 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) "Golden" Axis (Connected directly w/o switch 0 5000 10000 15000 20000 25000 30000 35000 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 1 0 5000 10000 15000 20000 25000 30000 35000 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 2 0 5000 10000 15000 20000 25000 30000 35000 0 2000 4000 6000 8000 10000 12000 14000 Clock Jitter (Nanoseconds) Axis Switch 3
  23. 23. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. 23 16 Axis Star, Linear K6500, Stratix 8000 Switch 16 Axis Star, K350, Stratix 2000 Switch So what do these numbers really mean? Average System Clock Jitter (Max) ~ 35 nanoseconds 0.000000035s x 6000 RPM/ 60s/min = 0.0000035 Revs Note: Sample from Axis 2 Average System Clock Jitter (Max) ~ 1.8 microseconds 0.0000018s x 6000 RPM/ 60s/min = 0.00018Revs Note: Sample from Axis 1, off switch 1 Multiply your application speed by this value to determine position error due to network jitter
  24. 24. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. PUBLIC INFORMATION Maximizing Machine Performance Topology Design Considerations
  25. 25. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. What’s new since last year?  A year’s worth of new testing has been completed  The latest products have been tested  3 Key Performance Indicators  Tracking Error  Registration Time Skew  Registration Position Skew  More data to back up our previous recommendations  Specific cell-based automation network guidelines intended for performance
  26. 26. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #1 Baseline Topology 30 Point I/O™ Adapters ArmorBlock™ I/OKinetix® 5500 or Kinetix 6500 Drives PowerFlex Drives PanelView™ Plus Plant Network (Any) Switch CIP Encoders Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime CompactLogix™ L36ERM Switch Topology QoS PTP Embedded Linear Direct Yes Yes (16) axes were tested in this topology
  27. 27. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #2: Linear Interposing Unmanaged (No QoS, No PTP) 31 CMX L36ERM Plant Network Stratix 2000 PanelView Plus Point I/O Adapters ArmorBlock I/OKinetix 5500 or Kinetix 6500 Drives CIP Encoders PowerFlex® Drives Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime Switch Topology QoS PTP Stratix 2000 Star/Linear No No (16) axes were tested in this topology
  28. 28. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #2a: Linear Direct Unmanaged (QoS, PTP in place) 32 Plant Network Stratix 2000 PanelView Plus Point I/O Adapters ArmorBlock I/OKinetix 5500 or Kinetix 6500 Drives CIP Encoders PowerFlex Drives CMX L36ERM Switch Topology QoS PTP Embedded Linear Direct Yes Yes (16) axes were tested in this topology Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime
  29. 29. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #3: Linear Interposing Low-Level Managed (No QoS, No PTP) 33 PanelView Plus Plant Network Stratix 5700 Lite Point I/O Adapters ArmorBlock I/OKinetix 5500 or Kinetix 6500 Drives PowerFlex Drives CMX L36ERM Switch Topology QoS PTP Stratix 5700 Lite Star/Linear No No CIP Encoders (16) axes were tested in this topology Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime
  30. 30. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #3a: Linear Direct Low-Level Managed (QoS, PTP in place) 34 PanelView Plus Plant Network Stratix 5700™ Lite Point I/O Adapters ArmorBlock I/OKinetix 5500 or Kinetix 6500 Drives PowerFlex Drives CIP Encoders CMX L36ERM Switch Topology QoS PTP Embedded Linear Direct Yes Yes (16) axes were tested in this topology Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime
  31. 31. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #4: Linear Interposing Mid-Level Managed (QoS, No PTP) 35 PanelView Plus Plant Network Point I/O Adapters ArmorBlock I/OKinetix 5500 or Kinetix 6500 Drives PowerFlex Drives Stratix 5700 Full ControlLogix L36ERM Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime Switch Topology QoS PTP Stratix 5700 Full Star/Linear Yes No (16) axes were tested in this topology CIP Encoders
  32. 32. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #4a: Linear Direct Mid-Level Managed (QoS, PTP in place) 36 PanelView Plus Plant Network Point I/O Adapters Kinetix 5500 or Kinetix 6500 Drives PowerFlex Drives Stratix 5700 Full CIP Encoders ArmorBlock I/O ControlLogix L36ERM Switch Topology QoS PTP Embedded Linear Direct Yes Yes (16) axes were tested in this topology Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime
  33. 33. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #5: Linear Interposing Fully Managed (QoS and PTP) 37 PanelView Plus Plant Network Stratix 5700 Full/PTP PowerFlex Drives Point I/O Adapters Kinetix 5500 or Kinetix 6500 Drives CIP Encoders ArmorBlock I/O CMX L36ERM Switch Topology QoS PTP Stratix 5700 Full/PTP Star/Linear Yes Yes (16) axes were tested in this topology Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime
  34. 34. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #6: STAR Interposing Fully Managed (QoS and PTP) 38 PanelView Plus Plant Network PowerFlex Drives Point I/O Adapters CIP Encoders ArmorBlock I/O Stratix 5700 Full/PTP ControlLogix L36ERM Switch Topology QoS PTP Stratix 5700 Full/PTP Star Yes Yes Kinetix 5500 or Kinetix 6500 Drives (8) axes were tested in this topology Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime
  35. 35. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Topology #7: STAR Interposing Mid-Level Managed (QoS, No PTP) PanelView Plus Plant Network PowerFlex Drives Point I/O Adapters ArmorBlock I/O Stratix 5700 Full 39 Switch Topology QoS PTP Stratix 5700 Full Star Yes No CIP Encoders Kinetix 5500 or Kinetix 6500 Drives Metric 0% Load 20% Load 40% Load Tracking RegPos RegTime CIP Encoders Did not test beyond (8) axes in this topology ControlLogix L36ERM
  36. 36. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Lessons Learned/Confirmed 40  For devices that include an embedded Ethernet switch:  Connect these devices directly to a controller (GM) when possible without an interposing switch  Use a PTP-capable switch if connected between GM and PTP- sensitive devices  Place any non-PTP capable switches at the end of the line of embedded switch products Stratix 5700 Full/PTP Any Switch
  37. 37. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. Lessons Learned/Confirmed 41  For single-port Ethernet products (like Kinetix 350 drives):  For 1-4 axes, offer a Stratix 2000 unmanaged switch*  For 5-8 axes, offer a Stratix 5700 Full managed switch*  Over 8 axes, offer a Stratix 5700 Full (PTP) managed switch  Use 1783-ETAP devices for ring topologies with Kinetix 350 drives * The application must not be marginal in terms of dynamics and accuracy requirements Stratix 2000 Kinetix 350 Drives Single Switch; no cascading ControlLogix L36ERM (4) axes were tested in this topology
  38. 38. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. We care what you think!  On the mobile app: 1. Locate session using Schedule or Agenda Builder 2. Click on the thumbs up icon on the lower right corner of the session detail 3. Complete survey 4. Click the Submit Form button 42 Please take a couple minutes to complete a quick session survey to tell us how we’re doing. 2 3 4 1 Thank you!!
  39. 39. Copyright © 2014 Rockwell Automation, Inc. All Rights Reserved. PUBLIC INFORMATION Questions?

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