RSLinx/ControlLogix Data Collection

1. RSLinx/ControlLogix Data Collection

2. Objectives • Discuss Common ControlLogix Data Collection Problems • Offer Solutions to Resolve These Issues

3. Common Data Collection Issues • Data updates are slow • Batch/Recipe downloads fail – Not all of the data gets to the CLX • Performance degrades when adding more HMI stations • Switching between different HMI screens takes too long • Items stop getting updates • Items stop getting updates temporarily • Other Issues?

4. ControlLogix Bandwidth • Relevant Issue: • Data updates are slow • Allocate enough time for communications • ControlLogix processing power needed for communications varies • System overhead time slice (continuous tasks) • Time between periodic tasks are scheduled (periodic tasks) • Number of Tags • Arrays, vs. UDT optimization, vs. scattered optimization • Motion and IO use communications bandwidth

5. Tasks and Communications • Continuous Tasks • Communication time is interleaved with running PLC code • Communication time allocated is proportional to time slice • Continuous task time will increase as time slice increases if more communications bandwidth is needed • Default task type • Periodic Tasks • Communications are halted while running PLC code • Task execution time is not effected by communications • The less frequently task is scheduled, more time for communications • Tightly scheduled periodic tasks will limit communications

6. Tasks and Communications • Using a Continuous Task and a Periodic Task • You are not required to have a periodic task • Reduces communications bandwidth • Tightly scheduled periodic tasks will limit communications • Multiple Periodic Tasks • Adds complexity to scheduling them and allocating communications bandwidth • Reduces communications bandwidth

7. Recommendations • Use One Continuous Task or One Periodic Task • Consider Consolidating Time Critical Control from Data Collection into Separate ControlLogix Processors

8. Periodic Task of 63 (ms) 5000 DINT Tags on Scan Periodic Task Scheduling

9. Continuous Task 5000 Tags on Scan in a 5555 (No Arrays or UDTs) Time Slice

10. Tag Organization and Comms • Relevant Issue • Data Updates are slow • Use arrays when possible • Less ControlLogix CPU needed • Less ControlLogix memory used • Use UDTs and Design Them with HMI in Mind • Performance similar to arrays • The more UDT elements consumed by data collection the better • RSLinx UDT optimization must be enabled • RSLinx must be able to optimize the UDT (480 bytes)

11. 5000 Tags on Scan in a 5555 Memory Consumption

12. Optimize Batch/Recipe Downloads • Relevant Issue • Batch/Recipe downloads fail – Not all of the data gets to the CLX • Use Write Optimization • ControlLogix Processor firmware 10.x or higher • RSLinx 2.30.02 or higher • RSLinx topic with optimize poke packets enabled • UDT Optimization • ControlLogix batch applications often use UDTs • As recipes run they often access various elements in the same UDTs

13. Optimize Batch/Recipe Downloads

14. Scalability – Getting Data into Multiple Stations • Relevant Issue • Performance degrades when adding more HMI stations • Use RSLinx Gateway (Remote OPC) • Optimizes network traffic and ControlLogix CPU • ControlLogix CPU and connections consumed for each RSLinx

15. Performance Degrades Without RSLinx Gateway • 5000 Tags on Scan in a 5555 (No Arrays or UDTs) • 50% Time Slice • 1 GHz Pentium III machines

16. 5000 Tags on Scan in a 5555 (No Arrays or UDTs) 50% Time Slice 1 GHz Pentium III machines RSLinx Gateway for Scalability

17. Operating/Maintaining Systems • Relevant Issue • Data stops updating • Data Collection Must Be Stopped and Restarted • Deleting tags in a ControlLogix Processor • Changing data type of a tag in a ControlLogix Processor • Changing array length of a tag in a ControlLogix Processor • Changing an alias tag in a ControlLogix Processor • Changing a UDT structure in a ControlLogix Processor • Data Collection Can Continue Uninterrupted • Adding tags to a ControlLogix processor • Adding tags to data collection applications

18. Operating/Maintaining Systems • Relevant Issue • Data stops updating • When ControlLogix Processor Tags Need To Be Changed or Deleted • Schedule a time for the ControlLogix downloads and employ a procedure to make updates • Don’t have to shut down HMIs • RSView has a NodeDisable command for example • Data collection can stop and start after the ControlLogix download

19. Redundancy • ControlLogix Hardware (processor, modules, power supply) • Two redundant racks synchronized by a 1757-SRM Module • Both redundant racks seen as one rack by RSLinx • Network, ControlLogix Hardware - RSLinx Alias Topics • Use switch on command only • Monitor a heartbeat on primary and backup(s). • Switch topics if heartbeat stops updating. • PC, Software, NIC – • RSLinx server redundancy • Multiple RSLinx Gateways

20. More Information • Application Guide - CLXPerf • http://www.software.rockwell.com/download/comms/rslinx/clx_perf.zip • Troubleshooting Guide • http://www.software.rockwell.com/download/comms/rslinx/controllogix%20data%20collection%20troubleshooting%20guide.doc