Rockwell Automation 1785-CHBM ControlNet PLC-5 Hot Backup System User Manual - Manual (Page 13)

Publication 1785-UM024B-EN-P - January 2003
Table of Contents v
Qualification: From No Control State to Primary State . . B-6
Qualification: From No Control State to Secondary State B-7
Reasons for Qualification Major Fault . . . . . . . . . . . . . B-14
Switchover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-14
Qualified Switchovers . . . . . . . . . . . . . . . . . . . . . . . . B-15
Unqualified Switchovers. . . . . . . . . . . . . . . . . . . . . . . B-16
Switchover Considerations . . . . . . . . . . . . . . . . . . . . . B-16
Data Table Crossloading Appendix C
Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Data Table Crossloading . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
On-Demand Data Table Crossloads . . . . . . . . . . . . . . . C-2
Optimizing On-Demand Crossloads . . . . . . . . . . . . . . . C-5
Triggering an On-Demand Data Table Crossload. . . . . . C-5
Qualification Crossloads . . . . . . . . . . . . . . . . . . . . . . . . C-6
Qualification Data Table Crossload . . . . . . . . . . . . . . . . C-7
Qualification State Data Table Crossload . . . . . . . . . . . . C-7
Data Table Crossload Time. . . . . . . . . . . . . . . . . . . . . . C-8
Data Table Crossload Data Latency . . . . . . . . . . . . . . . . C-8
Data Table Crossloading on ControlNet Channel . . . . . . C-9
Inhibiting Data Table Crossloads . . . . . . . . . . . . . . . . . C-9
Data Table Crossload Diagnostics . . . . . . . . . . . . . . . . . C-9
Data Table Crossloads Via Your Applications . . . . . . . C-10
Program Synchronization Appendix D
Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1
Program Synchronization. . . . . . . . . . . . . . . . . . . . . . . . . . D-1
Determining Which Mode to Use . . . . . . . . . . . . . . . . . D-2
Using Synchronous Mode. . . . . . . . . . . . . . . . . . . . . . . D-2
Determining the Maximum Program Scan Time. . . . . . . D-2
Adjusted Maximum Program Scan Time . . . . . . . . . . . . D-3
Program Scan Overrun . . . . . . . . . . . . . . . . . . . . . . . . . D-3
Application Guidelines Appendix E
Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Redundancy Considerations. . . . . . . . . . . . . . . . . . . . . . . . E-1
Switchover Considerations. . . . . . . . . . . . . . . . . . . . . . . . . E-2
Why Transfer Information? . . . . . . . . . . . . . . . . . . . . . . E-2
What Information Should Be Transferred? . . . . . . . . . . . E-3
When Should the Information Be Transferred? . . . . . . . E-4
How Often Should the Information Be Transferred?. . . . E-4
Performance Considerations . . . . . . . . . . . . . . . . . . . . . E-4
Inhibiting or Resetting ControlNet I/O . . . . . . . . . . . . . . . . E-5