State Industries GFK-0827 manual Faulting RCMs, Losing Links, and Terminating Communications

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Faulting RCMs, Losing Links, and Terminating Communications

There are distinct differences between losing a redundant communications link, faulting an RCM, and terminating communications.

Faulting the RCM module occurs only when a hardware related failure occurs such as a parity error or VME bus error.

Action taken when a board is faulted:

HModule Failed fault is logged in the PLC Fault Table.

HAll LEDs on the RCM module are turned OFF. The LEDs on the other RCM will continue to be updated as long as that RCM is OK.

HThe module fault contact is set.

HThe corresponding communications link is no longer used. If the other link is still operating, then that link will be used for all further data transfer and units can remain in synchronization.

HIf no other communications link is available, then the unit functions as a stand-alone unit when in RUN mode.

HA power cycle, after replacement of the faulted RCM, is required to restore the RCM to service.

Losing a Link occurs when a link timeout occurs (that is, no data received in the expected time period). Since the system is not certain that a lost link is due to a hardware failure, the RCM is not faulted. Some possible causes for a link timeout are:

1.Remote unit has failed and is unable to communicate.

2.Configured fail-wait timeout is too short and a long sweep or communications window has resulted in a link timeout. Normally the other link will continue to function in this case and the systems remain synchronized. If the condition continues, the remaining communications link will timeout in a subsequent sweep.

3.A hardware problem is present that prevents data from being transferred but is not detectable by error checking mechanisms such as parity errors (there are no known problems in this category).

Action taken when a link has timed out.

HLink Timeout fault is logged in the PLC Fault Table.

HThe OK and Local LEDs on the RCM in the RCM to BTM link that failed will continue to be maintained (that is, they will stay ON and the Local LEDs will reflect the state of the Local unit) but the Remote LEDS will be turned OFF. The LEDs on the other RCM will continue to be updated as long as that RCM is OK.

HThe module fault contact is set.

HThe corresponding communications link is no longer used. If the other link is still operating, then that link will be used for all further data transfer and units can remain in synchronization.

HIf no other communications link is available, then the unit functions as a stand-alone unit when in RUN mode.

HA power cycle of either unit is required to restore the link to service.

GFK-0827

Chapter 4 Operation

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Contents GE Fanuc Automation GFL±002 Content of this Manual Related PublicationsPreface We Welcome Your Comments and SuggestionsContents Chapter System Components Chapter Configuration Chapter Operation System Operation Fault Detection and Control Actions Synchronized Hot Standby CPU Redundancy System Configuration Contents Chapter Introduction Hot Standby CPU Redundancy ProductGFK-0827 Features of the Hot Standby CPU Redundancy Product Benefits of the Hot Standby CPU Redundancy ProductLocal I/O System Systems for Hot Standby CPU Redundancy SystemsGenius I/O System Cable ConnectionsBasic Hot Standby Operation Control StrategySynchronized Hot Standby CPU Redundancy System Configuration Redundancy CPU Module Redundancy Communications ModuleSynchronized CPUs Bumpless SwitchingSwitch to Backup Unit Time Effect on Scan TimeOn-Line Repair Configurable Backup Data SizeOn-Line Programming Configuration Requirements Programming ConsiderationsDefinition of Terms Term DefinitionCommonly Used Acronyms Acronym DefinitionChapter System Components Redundancy CPUCapacities for Redundancy CPU, IC697CPU780 Watchdog TimerCPU Architecture CPU Features Redundancy CPU IC697CPUCPU Mode Switch Valid Operating Mode SelectionCPU Status LEDs Memor y Protect KeyswitchBattery Connectors Expansion Memory Boards for CPU Serial Port ConnectorExpansion Memory Board RCM Features Redundancy Communications ModuleRCM System Status Leds Board OKRCM Connectors Unit Selection PushbuttonLED Status Indicators Bus Transmitter ModuleBTM Connectors Bus Receiver ModuleGenius Bus Controller Bus Signal TerminationBRM Connectors Genius Bus Controller User Features GBC Connectors RacksChapter Configuration Configuring a Hot Standby CPU Redundancy SystemSystem Configuration Basic Redundancy System SetupLogicmaster 90 Configuration Redundancy System RequirementsScreens for Fault Category Configuration Monitor or Online modeConfiguration with Logicmaster Handling FoldersConfiguration of a Redundancy CPU Module GFK-0827 Redundant CPU Requirements Background Window Normal Sweep ModeRedund Type Constant Window Sweep Mode Constant Sweep ModeShared I/O Ctrl StrgyFail Wait Shared I/O Data Parameters Shared I/O Reference ValuesTransfer Data Size Reference Type ReferenceSize CalculationforNumberofBytesConfiguring a CPU Expansion Memory Board Configuration of a Redundancy Communications Module Configuration Configuration of a Genius Bus Controller Paired GBC ParameterSerial Bus Address Configuring a Primary Redundant PLC Select the Redundancy CPU Module Select an Expansion Memory Board Configure the Redundant Communications Module Configure a Genius Bus Controller Configuration Configure Genius I/O Blocks Configure the Bus Transmitter Module Configuring a Secondary Redundant PLC Change Redund Type GFK-0827 Power-Up Sequence of a Redundant CPU Chapter OperationIncompatible Configurations Resynchronization of the Redundant CPU Hot-Standby Redundancy Control Strategy Synchronous Scan First Data Transfer %I, %AI and SynchronizationData Transfer from Backup Unit to Active Unit Switching Control to Backup Unit Second Data Transfer %Q, %AQ, %R, and %MRole Switch Svcreq References for CPU Redundancy Definition for% S Reference for Redundancy StatusRedundancy CPU Considerations RUN Disabled Mode Differences in Operation for CPURUN/ENABLED Locrdy Locact Remrdy Remact Configuration of Fault Actions Stop to RUN Mode Transition Background Window TimeWords per Sweep = Timed Contacts Ovrpre %S ReferenceGenius Bus Controller Switching Fault Detection Fault CategoriesChanging Fault Category Actions PLC Fault Table Fault Zoom Help Text for Redundancy Error CodesFaulting RCMs, Losing Links, and Terminating Communications GFK-0827 Fault Actions in a CPU Redundancy System Maskable Fault Group DescriptionsMaskable Fault Group Actions UserConfigurableNon-Maskable Fault Group Descriptions Non-Maskable Fault Action DescriptionsOn-Line Repair Recommendations On-Line RepairMaintaining Parallel Bus Termination Central Processor Unit Power SupplyRacks Redundancy Communications Module and CablesGenius Bus Controller Redundancy Communications Link FailuresBus Transmitter Module Genius Bus GeniusBlocksAppendix Redundancy Alternatives Redundancy AlternativesRedundancy Option Key See Table RedundancyOptions PLCSeries 90-70 Redundancy Through Application Logic Index Index Index Index Index
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