GE 90-70 manual Genius Bus Controller Switching

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4

Genius Bus Controller Switching

Genius Bus Controllers stop sending outputs to Genius I/O blocks when no output data has been received from the PLC CPU for a period equal to two times the configured watchdog timeout.

If the CPU in the Primary Unit becomes inoperative in an uncontrolled fashion (for example, because of a power failure), the Genius Bus Controllers detect this within twice the watchdog setting, and stop sending outputs to the Genius blocks. After three Genius I/O bus scans of not receiving data from the Genius Bus Controllers at Serial Bus Address 31, the Genius blocks start driving data from Serial Bus Address 30 (the Secondary Unit) if available.

For example, if the system has a 200ms watchdog timeout and 5ms Genius bus scan time, and the Primary Unit main rack loses power, the Genius Bus Controllers in expansion racks will wait 400ms and then stop updating outputs on Genius blocks. After 15ms, the blocks will begin driving outputs based on data from the Secondary Unit. Note that any Genius Bus Controllers in the main rack would stop driving outputs immediately since they would also lose power. Genius blocks on these busses would begin driving data from the Secondary Unit within 15ms.

Note

For the GHS Control Strategy, if the Secondary Unit is the active unit, outputs are disabled in the Primary Unit. Outputs from Serial Bus Address 31 are not immediately available in this case. Therefore, the outputs could go temporarily to their default state on failure of the Secondary Unit. For this reason, the Primary Unit should normally be selected as the active unit when using the GHS Control Strategy.

Note

For fastest switching, all Genius Bus Controllers in the Hot Standby CPU Redundancy system should be in the main rack, or in a rack driven by the main rack's power supply. This causes the Genius Bus Controller to lose power at the same time that the CPU loses power. This, in turn, allows the backup unit to gain full control of the I/O as soon as possible.

For single bus Genius networks, if outputs are not available on Serial Bus Address 30 or 31, then the block’s outputs revert to default or hold last state (as configured).

For dual bus networks, if outputs are not available on Serial Bus Address 30 or 31, then the BSM will switch to the other bus. If outputs are not available on either bus, then the block’s outputs revert to default or hold last state (as configured).

GFK-1527A

Chapter 4 Normal Operation

4-23

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Page 61 Page 63
Contents GE Fanuc Automation GFL-002 Related Publications Content of This ManualPreface Preface Contents Contents Chapter Fault Detection Appendix a Cabling Information Introduction Definition of TermsEnhanced Hot Standby CPU Redundancy Using the Redundancy CPU for Non-Redundant Operation Compatibility with CPU780Differences in Operation for Redundancy CPUs Features not Available with Redundancy CPUsRedundancy CPUs as Compared to Other Series 90-70 CPUs Redundant Racks Enhanced Redundancy CPU ModuleRedundancy Communications Module Systems for Enhanced Hot Standby CPU RedundancyCable Connections Genius I/OLocal I/O Enhanced Hot Standby CPU Redundancy System with Local I/O Local I/0 Can beGDB Control Strategy Control StrategiesGHS Control Strategy Output Control with GDB Basic Enhanced Hot Standby OperationOutput Control with GHS Basic CPU Redundancy Setups Single Bus with Preferred Master GHS Control StrategySingle Bus with Floating Master GDB Control Strategy Critical Data + Redundant Outputs TransferredDual Bus with Floating Master GDB Control Strategy Paired GBC = INT/EXT Internal ExternalDuplex CPU Redundancy Online ProgrammingOn-Line Repair System Racks For Installation InstructionsSystem Components Features Redundancy CPUExpansion Memory Board Watchdog TimerCPU Architecture Battery Connectors CPU FeaturesMemory Protect Keyswitch CPU LEDsCPU Mode Switch PortRedundancy Communications Module Unit Select PushbuttonConnector RCM Status LedsBus Transmitter Module Status LEDs ConnectorsBus Transmitter Module Bus Receiver Module Status LEDs Bus Receiver ModuleCables and Termination Genius Bus Controller Location of GBCs and BlocksSingle Bus Genius Networks Dual Bus Genius NetworksBus Controller LEDs One Application Program in Both PLCs Configuration RequirementsProgrammer Connection for Configuration Program Folders in Control Programming SoftwareCPU Configuration Parameters Program Folders in LogicmasterConfiguring Shared I/O References Parameter Default Range DescriptionFinding the Memory Available for Application Program Storage System Communications Window ConsiderationsRack Module Configuration Parameters Bus Controller Configuration ParametersGenius I/O Block Configuration Parameters Normal Operation Powerup of a Redundant CPU Incompatible Configurations Resynchronization of a Redundant CPUGHS Control Strategy GDB Control StrategyReferences for CPU Redundancy Ovrpre %S Reference Not AvailableScan Synchronization Sweep Time SynchronizationOutput Data Transfer to the Backup Unit AT aData Transfer Time Fail Wait TimeGFK-1527A Normal Operation Programming a Data Transfer from Backup Unit to Active Unit Data Transfer ExampleDisabling Data Transfer Copy in Backup Unit Svcreq #43 Command Block for Svcreq #43 Validating the Backup PLCs Logic Solution Backup Qualification with Svcreq #43Validating the Backup PLCs Input Scan Switching Control to the Backup Unit Switching TimesExample 1 Role switches allowed on both units RUN Disabled ModeRUN Disabled Mode for GHS Control Strategy Example 4 Role switches allowed on both units Example 2 Role switches allowed on both unitsExample 3 Role switches not allowed on either unit Backup Active RUN Disabled Mode for GDB Control Strategy Example 8 InvalidFinding the Words to Checksum Each Sweep CGR772 CGR935Finding the Background Window Time Finding the Total Sweep TimeTimed Contacts Timer and PID Function BlocksMiscellaneous Operation Information Multiple I/O Scan SetsDebugger Stop to RUN Mode TransitionSequential Function Chart Programming SFC Background Window TimeGenius Bus Controller Switching Ethernet Global Data in a Redundancy CPU Ethernet Global Data ConsumptionEthernet Global Data Production Sntp TimestampingFault Detection Configuration of Fault ActionsFault Detection PLC Fault Table Messages for Redundancy Message Fault Description Corrective ActionWith redundancy in other fault groups Fault Response Faulting the Redundancy Communications Module Losing a LinkFault Actions in a CPU Redundancy System Configurable Faults Fault Group Type DescriptionNon-Configurable Fault Group Fatal Faults on Both Units in the Same SweepOn-Line Repair On-Line Repair Recommendations Power SupplyMaintaining Parallel Bus Termination RacksRedundancy Communications Link Failures Central Processor UnitRedundancy Communications Module and Cables Genius Bus Controller Single Bus Networks Bus faultsBus Transmitter Module Genius BusDual Bus Networks Genius BlocksIC690CBL714A Multi-drop Cable SpecificationsCabling Information PurposeConnector a Connector A, 15-pin Female Battery connectors Bus Controller, Genius IndexIndex Online programming Online repair Svcreq
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