SPRADH0 August   2024 AM625 , AM6442 , AM69 , TDA4VM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 What is EtherCAT?
    2. 1.2 What is a PLC?
    3. 1.3 What is CODESYS?
  5. 2Evaluation Platform and Methods
    1. 2.1 Hardware
    2. 2.2 Software
    3. 2.3 Test Topology
  6. 3Performance Metrics
    1. 3.1 Cyclictest Performance Metrics
    2. 3.2 EtherCAT Performance Metrics
  7. 4Optimizations
    1. 4.1 Implemented Optimizations
    2. 4.2 Future Considerations
      1. 4.2.1 Set Maximum CPU Frequency
      2. 4.2.2 Isolate Cores
      3. 4.2.3 Set CPU Affinity
      4. 4.2.4 Isolate Cores and Set CPU Affinity
      5. 4.2.5 Ksoftirqs to FIFO
      6. 4.2.6 Increase the Real-Time Scheduling Time
      7. 4.2.7 Disable irqbalance
      8. 4.2.8 Use Separate Network Interface Card (NIC)
      9. 4.2.9 Disable Unnecessary Drivers
  8. 5Summary
  9. 6References
  10. 7Appendix A: How to Setup TI Embedded Processors as EtherCAT Controller Using the CODESYS Stack
    1. 7.1 Hardware Requirements
    2. 7.2 Software Requirements
    3. 7.3 Hardware Setup
    4. 7.4 Software Setup
      1. 7.4.1 Windows PC Setup
      2. 7.4.2 EtherCAT Controller Setup
      3. 7.4.3 CODESYS Development System Project
      4. 7.4.4 Execution
    5. 7.5 How to View Performance Measurements
      1. 7.5.1 Appendix A Resources
  11. 8Appendix B: How to Enable Unlimited Runtime on CODESYS Stack
    1. 8.1 CODESYS Licensing Background
    2. 8.2 Obtaining a CODESYS License
    3. 8.3 Activating CODESYS License
      1. 8.3.1 Background
      2. 8.3.2 Recommended Steps
    4. 8.4 Verifying CODESYS License Applied
      1. 8.4.1 Known Issues With Verifying CODESYS License Applied

4.2.6 Increase the Real-Time Scheduling Time

The Linux kernel places a global limit on how much time threads with a real-time scheduling policy can use. The remaining time is used to schedule SCHED_OTHER processes. Increasing the allocated real-time scheduling time can help to prevent real-time threads from missing deadlines including the EtherCAT task thread and the ksoftirq threads. By default on RT-Linux, the real-time allocated runtime can be read from /proc/sys/kernel/sched_rt_runtime _us to be 950000 or 0.95 seconds. The entire measurement period can be read from /proc/sys/kernel/sched_rt_period_us to be 1000000 or 1 second. Based on these runtimes, by default, 0.05 seconds is reserved for SCHED_OTHER threads. Completely setting real-time runtime to be 1 second is not recommended; however, increasing the real-time runtime to 0.98 or 0.99 seconds can be helpful.