GE 90-70 manual Powerup of a Redundant CPU

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Powerup of a Redundant CPU

When a redundant CPU is powered up, it performs a complete hardware diagnostic check and a complete check of the application program and configuration parameters. This causes the powerup time of a redundant CPU to be significantly longer than the normal powerup time of a non- redundant CPU. If the Primary and Secondary systems power up together each CPU will recognize this fact so that the Primary system will become the active and the Secondary system the backup.

Powerup consists of the following sequence of steps:

1.Powerup self-test is always performed.

2.CPU operating system is initialized and PLC memory is validated.

3.Diagnostics called during full powerup tests are performed.

4.System Configuration is verified.

5.System is interrogated and initialized.

6.Presence of other CPU is detected.

7.Redundancy Communications Modules are initialized.

8.Complete application program is verified.

9.CPU synchronizes with redundant CPU.

When the Secondary Unit powers up, if it does not detect the Primary Unit, the Secondary Unit waits up to 15 seconds for the Primary Unit to power up. If the primary unit has not completed its powerup sequence within 15 seconds, the Secondary Unit assumes the Primary Unit is not present. If at this time, the Secondary Unit transitions to RUN mode, it does so as an active unit without a backup unit.

If the Primary Unit completes its powerup sequence before the Secondary Unit, the Primary Unit does not wait for the Secondary unit to complete its powerup sequence. If the Primary Unit is set up to transition to RUN on powerup (that is, was powered-down in RUN mode), it transitions to a stand-alone unit without waiting for the Secondary unit. The Secondary Unit, upon completion of its powerup sequence, establishes communications with the Primary Unit. If transitioning to Run mode, it synchronizes with the Primary Unit.

In either case, if one CPU fails to notify the other CPU that it is either present or powering up, the other CPU, if transitioning to RUN, becomes the active unit and runs without a backup unit. Resynchronization occurs after the powerup sequence is complete.

Note

If the system should be fully redundant upon powerup, the Secondary Unit must complete power-up first but no more than 15 seconds before the Primary Unit. The way to be sure this happens is to apply power to the Secondary Unit first.

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Series 90™-70 Enhanced Hot Standby CPU Redundancy User's Guide – May 2000

GFK-1527A

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Contents GE Fanuc Automation GFL-002 Related Publications Content of This ManualPreface Preface Contents Contents Chapter Fault Detection Appendix a Cabling Information Definition of Terms IntroductionEnhanced Hot Standby CPU Redundancy Compatibility with CPU780 Using the Redundancy CPU for Non-Redundant OperationDifferences in Operation for Redundancy CPUs Features not Available with Redundancy CPUsRedundancy CPUs as Compared to Other Series 90-70 CPUs Redundancy Communications Module Enhanced Redundancy CPU ModuleRedundant Racks Systems for Enhanced Hot Standby CPU RedundancyCable Connections Genius I/OLocal I/O Local I/0 Can be Enhanced Hot Standby CPU Redundancy System with Local I/OGDB Control Strategy Control StrategiesGHS Control Strategy Output Control with GDB Basic Enhanced Hot Standby OperationOutput Control with GHS Single Bus with Preferred Master GHS Control Strategy Basic CPU Redundancy SetupsCritical Data + Redundant Outputs Transferred Single Bus with Floating Master GDB Control StrategyPaired GBC = INT/EXT Internal External Dual Bus with Floating Master GDB Control StrategyDuplex CPU Redundancy Online ProgrammingOn-Line Repair System Racks For Installation InstructionsSystem Components Redundancy CPU FeaturesExpansion Memory Board Watchdog TimerCPU Architecture Memory Protect Keyswitch CPU FeaturesBattery Connectors CPU LEDsPort CPU Mode SwitchUnit Select Pushbutton Redundancy Communications ModuleRCM Status Leds ConnectorBus Transmitter Module Status LEDs ConnectorsBus Transmitter Module Bus Receiver Module Status LEDs Bus Receiver ModuleCables and Termination Location of GBCs and Blocks Genius Bus ControllerDual Bus Genius Networks Single Bus Genius NetworksBus Controller LEDs Programmer Connection for Configuration Configuration RequirementsOne Application Program in Both PLCs Program Folders in Control Programming SoftwareProgram Folders in Logicmaster CPU Configuration ParametersParameter Default Range Description Configuring Shared I/O ReferencesSystem Communications Window Considerations Finding the Memory Available for Application Program StorageBus Controller Configuration Parameters Rack Module Configuration ParametersGenius I/O Block Configuration Parameters Normal Operation Powerup of a Redundant CPU Resynchronization of a Redundant CPU Incompatible ConfigurationsGDB Control Strategy GHS Control StrategyOvrpre %S Reference Not Available References for CPU RedundancySweep Time Synchronization Scan SynchronizationAT a Output Data Transfer to the Backup UnitFail Wait Time Data Transfer TimeGFK-1527A Normal Operation Data Transfer Example Programming a Data Transfer from Backup Unit to Active UnitDisabling 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 Times Switching Control to the Backup UnitExample 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 Example 8 Invalid RUN Disabled Mode for GDB Control StrategyCGR772 CGR935 Finding the Words to Checksum Each SweepFinding the Total Sweep Time Finding the Background Window TimeMiscellaneous Operation Information Timer and PID Function BlocksTimed Contacts Multiple I/O Scan SetsSequential Function Chart Programming SFC Stop to RUN Mode TransitionDebugger Background Window TimeGenius Bus Controller Switching Ethernet Global Data Consumption Ethernet Global Data in a Redundancy CPUSntp Timestamping Ethernet Global Data ProductionConfiguration of Fault Actions Fault DetectionFault Detection Message Fault Description Corrective Action PLC Fault Table Messages for RedundancyWith redundancy in other fault groups Fault Response Losing a Link Faulting the Redundancy Communications ModuleFault Actions in a CPU Redundancy System Fault Group Type Description Configurable FaultsFatal Faults on Both Units in the Same Sweep Non-Configurable Fault GroupOn-Line Repair Maintaining Parallel Bus Termination Power SupplyOn-Line Repair Recommendations RacksRedundancy Communications Link Failures Central Processor UnitRedundancy Communications Module and Cables Bus Transmitter Module Single Bus Networks Bus faultsGenius Bus Controller Genius BusGenius Blocks Dual Bus NetworksCabling Information SpecificationsIC690CBL714A Multi-drop Cable PurposeConnector a Connector A, 15-pin Female Index Battery connectors Bus Controller, GeniusIndex Online programming Online repair Svcreq
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