GE 90-70 manual Maintaining Parallel Bus Termination, On-Line Repair Recommendations, Power Supply

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Maintaining Parallel Bus Termination

It is important when doing online repair to maintain parallel bus termination on the active unit. This is the reason a terminated parallel cable (IC697CBL803, IC697CBL811 or IC697CBL826) is used, and why the Redundancy Communications Module must be the last device on the parallel bus. The terminated end of the cable may be safely removed from a de-energized RCM. The terminated cable should be considered an integral part of the unit it terminates.

On-Line Repair Recommendations

It is advised when doing online repair to power-off the entire PLC system (of the suspect unit), including ALL RACKS. Change the suspect part, and power-up in STOP mode. Verify that the links are operational before switching to RUN (%S bits and RCM LEDs are updated in STOP mode).

Power Supply

The power supply has adequate internal fault detection, which causes it to automatically shut down if there is a failure.

A power supply failure is indicated by the absence of the OK indication at the power supply. There are a small number of failures that can result in a false indication or no indication. The probability of these occurring are extremely low compared to the major failure items of the power supply.

In the event of a power supply failure, the backup CPU takes control of the system. The power supply can be replaced with power removed from its rack without interruption to the application being controlled.

Caution

Before replacing a power supply, be sure to disconnect main power to the rack, since incoming power will be present on the power supply terminals

When the power supply is replaced, power can be returned to the rack. The CPU will then obtain synchronization with the active system and either take control or become the backup CPU.

Racks

The only detectable rack failure is bad data across the backplane. This bad data can take the form of a bad control line as well as a bad data or address line. In most cases bad data lines are detected by the data integrity checks associated with the data transfers. If these occur the PLC is faulted and control transfers to the backup unit. An indication is given that a data transfer error has occurred.

There is no single indication that a rack failure has occurred. The rack is a very reliable component in the system and rack failures are extremely rare. A rack failure (other than a catastrophic rack failure) can only be correctly diagnosed by process of elimination.

GFK-1527A

Chapter 5 Fault Detection

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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 Definition of Terms IntroductionEnhanced Hot Standby CPU Redundancy Compatibility with CPU780 Using the Redundancy CPU for Non-Redundant OperationFeatures not Available with Redundancy CPUs Redundancy CPUs as Compared to Other Series 90-70 CPUsDifferences in Operation for Redundancy CPUs Systems for Enhanced Hot Standby CPU Redundancy Enhanced Redundancy CPU ModuleRedundancy Communications Module Redundant RacksGenius I/O Local I/OCable Connections Local I/0 Can be Enhanced Hot Standby CPU Redundancy System with Local I/OControl Strategies GHS Control StrategyGDB Control Strategy Basic Enhanced Hot Standby Operation Output Control with GHSOutput Control with GDB 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 StrategyOnline Programming On-Line RepairDuplex CPU Redundancy For Installation Instructions System ComponentsSystem Racks Redundancy CPU FeaturesWatchdog Timer CPU ArchitectureExpansion Memory Board CPU LEDs CPU FeaturesMemory Protect Keyswitch Battery ConnectorsPort CPU Mode SwitchUnit Select Pushbutton Redundancy Communications ModuleRCM Status Leds ConnectorConnectors Bus Transmitter ModuleBus Transmitter Module Status LEDs Bus Receiver Module Cables and TerminationBus Receiver Module Status LEDs Location of GBCs and Blocks Genius Bus ControllerDual Bus Genius Networks Single Bus Genius NetworksBus Controller LEDs Program Folders in Control Programming Software Configuration RequirementsProgrammer Connection for Configuration One Application Program in Both PLCsProgram 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 Backup Qualification with Svcreq #43 Validating the Backup PLCs Input ScanValidating the Backup PLCs Logic Solution Switching Times Switching Control to the Backup UnitRUN 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 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 TimeMultiple I/O Scan Sets Timer and PID Function BlocksMiscellaneous Operation Information Timed ContactsBackground Window Time Stop to RUN Mode TransitionSequential Function Chart Programming SFC DebuggerGenius 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 Racks Power SupplyMaintaining Parallel Bus Termination On-Line Repair RecommendationsCentral Processor Unit Redundancy Communications Module and CablesRedundancy Communications Link Failures Genius Bus Single Bus Networks Bus faultsBus Transmitter Module Genius Bus ControllerGenius Blocks Dual Bus NetworksPurpose SpecificationsCabling Information IC690CBL714A Multi-drop CableConnector a Connector A, 15-pin Female Index Battery connectors Bus Controller, GeniusIndex Online programming Online repair Svcreq
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