GE 90-70 manual Finding the Background Window Time, Finding the Total Sweep Time

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Example

The example below calculates Words per Sweep for a CGR935. It uses the following data:

User Program Size = 239000

Program Size = User Program Size + 11000 = 239000 + 11000 = 250000 bytes

Sweep Time = 100 ms

Max Completion Time = 60000 (1 minute)

	250000 x 100
Words per Sweep =	----------------------------------------------------- = 208.4
	[60000 - (250000 x 0.0014) - 376] x 2

Words per Sweep = 216 (rounded up to next number divisible by 8)

Finding the Background Window Time

Next, use the calculated Words per Sweep in the following formula to determine how long to set the background window time.

C x (Sweep Time + Words per Sweep x F x 2)

Background Window Time = ---------------------

(Max. Completion Time - C)

Here, the background window time is the time in milliseconds that you should set the background window timer. The other elements in the formula are described above. For our example, the background window time is:

	376 x (100 + 216 x 0.0014 x 2)
Background Window Time =	-------------------------- = 0.63ms
	(60000 - 376)

Background Window Time = 1ms (rounded up to next ms)

Finding the Total Sweep Time

The final sweep time can therefore be estimated to be:

Final Sweep Time = Sweep Time + (Words per Sweep x F x 2) + Background Window Time

For our example, the sweep time is:

Final Sweep Time = 100 + (216 X 0.0014 X 2) + 1 = 101.6ms

4-20

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 Systems for Enhanced Hot Standby CPU Redundancy Enhanced Redundancy CPU ModuleRedundancy Communications Module Redundant RacksCable 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 CPU LEDs CPU FeaturesMemory Protect Keyswitch Battery ConnectorsPort 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 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 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 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 RecommendationsRedundancy Communications Link Failures Central Processor UnitRedundancy Communications Module and Cables 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