GE 90-70 manual Fault Detection

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2. If an expansion rack fails after a unit becomes a stand-alone unit, a diagnostic fault will be logged on that unit but the unit will stay in RUN mode and continue to control the process.

3. If after the above situation occurs, the other unit transitions to RUN, the unit with the failed expansion rack will stay in RUN mode and may, depending on the configuration, remain in control of the process. You may want to include logic to shut down the faulted unit or request a role switch if this is an undesired operation.

Also, a unit with the fault actions set to diagnostic may be placed in RUN mode and become the active unit even though it may have a diagnostic fault, which would be logged as fatal in a synchronized system.

For example, if an expansion rack fails while in STOP mode or while transitioning to RUN mode, a diagnostic fault is logged; however, the unit will still transition to RUN and may, depending on configuration, become the active unit. You may want to include logic to shut down the faulted unit or request a role switch if this is an undesired operation.

Fault Detection

The detection of faults and failures falls into three basic categories:

1.faults and failures that are detected immediately

2.faults and failures that are detected as soon as possible, but not necessarily within the current sweep

3.faults and failures that are detected in the background.

Faults and failures that are detected immediately are those that are identified within the current sweep. These faults include I/O data corruption, single bit RAM failures, power supply failures, processor failures, VME bus failures, and no response from an addressed VME module.

Faults and failures that are detected as soon as possible, but not necessarily within the current sweep, include a group of faults that are detected asynchronously to the PLC sweep (Genius faults) or those faults that require a timeout larger than one sweep time to detect the failure. These faults are typically detected within one second and include all Genius faults (circuit faults, loss of block, and so forth).

Faults and failures that are detected in the background will typically be detected within 30 seconds. These faults include address or data line failures, multiple bit RAM failures, firmware failures, and communication device failures.

Note

The actual time to run all diagnostics tests is determined by configuration parameters as described in Chapter 4. This time might be more or less than 30 seconds.

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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 Content of This Manual PrefaceRelated Publications 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 CPU780Features not Available with Redundancy CPUs Redundancy CPUs as Compared to Other Series 90-70 CPUsDifferences in Operation for Redundancy CPUs Redundant Racks Enhanced Redundancy CPU ModuleRedundancy Communications Module Systems for Enhanced Hot Standby CPU RedundancyGenius I/O Local I/OCable Connections Enhanced Hot Standby CPU Redundancy System with Local I/O Local I/0 Can beControl Strategies GHS Control StrategyGDB Control Strategy Basic Enhanced Hot Standby Operation Output Control with GHSOutput Control with GDB 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 ExternalOnline Programming On-Line RepairDuplex CPU Redundancy For Installation Instructions System ComponentsSystem Racks Features Redundancy CPUWatchdog Timer CPU ArchitectureExpansion Memory Board Battery Connectors CPU FeaturesMemory Protect Keyswitch CPU LEDsCPU Mode Switch PortRedundancy Communications Module Unit Select PushbuttonConnector RCM Status LedsConnectors Bus Transmitter ModuleBus Transmitter Module Status LEDs Bus Receiver Module Cables and TerminationBus Receiver Module Status LEDs 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 Backup Qualification with Svcreq #43 Validating the Backup PLCs Input ScanValidating the Backup PLCs Logic Solution Switching Control to the Backup Unit Switching TimesRUN Disabled Mode RUN Disabled Mode for GHS Control StrategyExample 1 Role switches allowed on both units Example 2 Role switches allowed on both units Example 3 Role switches not allowed on either unitExample 4 Role switches allowed on both units 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 RacksCentral Processor Unit Redundancy Communications Module and CablesRedundancy Communications Link Failures 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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