Bringing Together Leading Brands in Industrial Aut Complete Automation TM on the Move Complete Automation TM on the Move RSLinx/ ControlLogix Data Collection
Jan 03, 2016
Bringing Together Leading Brands in Industrial Automation
Complete AutomationTM
on the Move
Complete AutomationTM
on the Move
RSLinx/ControlLogix Data Collection
ObjectivesObjectives
• Discuss Common ControlLogix Data Collection Problems
• Offer Solutions to Resolve These Issues
Common Data Collection IssuesCommon 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?
ControlLogix BandwidthControlLogix 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
Tasks and CommunicationsTasks 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
Tasks and CommunicationsTasks 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
RecommendationsRecommendations
• Use One Continuous Task or One Periodic Task
• Consider Consolidating Time Critical Control from Data Collection into Separate ControlLogix Processors
Periodic Task SchedulingPeriodic Task Scheduling
• Periodic Task of 63 (ms)
• 5000 DINT Tags on Scan
Periodic Task Rate
Tags Per Second
64 260
70 1300
100 4840
200 8890
300 10250
400 10950
500 11350
Time SliceTime Slice
• Continuous Task
• 5000 Tags on Scan in a 5555 (No Arrays or UDTs)
Time Slice Max Scan Time
Tags per Second
10% 139 1270
20% 158 2680
30% 183 4070
40% 218 5340
50% 266 6620
60% 339 7940
70% 465 9190
80% 695 10360
90% 1472 11530
Tag Organization and CommsTag 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)
Memory ConsumptionMemory Consumption
• 5000 Tags on Scan in a 5555
Tag Type Tags Per second
ControlLogix Optimized Packets
CLX Memory
Consumption (Bytes)
Isolated Integers
975 41 208,828
Integers in UDTs
6600 23 18,372
Array of Integers
7240 21 17,860
Optimize Batch/Recipe DownloadsOptimize 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
Optimize Batch/Recipe DownloadsOptimize Batch/Recipe Downloads
Scalability – Getting Data into Multiple StationsScalability – 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
Performance Degrades Without RSLinx GatewayPerformance Degrades Without RSLinx Gateway
• 5000 Tags on Scan in a 5555 (No Arrays or UDTs)• 50% Time Slice• 1 GHz Pentium III machines
Number of RSLinx stations collecting Data
Time between updates
Tags per Second
1 .74 6710
2 1.56 3355
3 2.1 2220
4 2.95 1660
5 3.7 1340
RSLinx Gateway for ScalabilityRSLinx Gateway for Scalability
• 5000 Tags on Scan in a 5555 (No Arrays or UDTs)• 50% Time Slice• 1 GHz Pentium III machines
Number of Remote OPC Stations Collecting Data from an RSLinx Gateway
Time between updates
Tags per
Second
RSLinx Gateway Virtual Memory (M)
CPU utilization of RSLinx Gateway
1 .75 6710 30.01 36%
2 .75 6710 33.11 47%
3 .75 6710 33.72 47%
4 .75 6710 34.3 55%
5 .75 6710 36.93 71%
Operating/Maintaining SystemsOperating/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
Operating/Maintaining SystemsOperating/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
RedundancyRedundancy• 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
More InformationMore 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