GE 90-70 manual Finding the Words to Checksum Each Sweep, CGR772 CGR935

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4

Background User Checksum and Background Window Timing Instructions

Performing User program Checksum verification and Background Window Diagnostics adds time to the sweep; the more checksums and diagnostics that are performed each sweep, the longer the sweep will take. For example, setting the Words to Checksum to 216 adds about 0.6 ms to each sweep in a CGR935 (216 words x 2 bytes/word x 0.0014 ms/byte = 0.6 ms).

For users wanting to compare Program Checksum verification and Background Window Diagnostics within a set amount of time (for example, 60 seconds), the following formula can be used to estimate the necessary settings for Words to Checksum and Background Window Time.

hese calculations can be used for Normal Sweep mode or Constant Window mode. They are not valid for Constant Sweep mode.

Finding the Words to Checksum Each Sweep

First, you should determine the number of words to checksum each sweep.

Program Size x Sweep Time

Words per Sweep = ------------------------------------------------------------------------

[Max. Completion Time - (Program Size x F) - C] x 2

Where:

Words per Sweep: The number of words to set in the PLC Configuration to be checksummed each sweep. The number calculated must be rounded up to the next number divisible by 8 (8, 16, 24, etc.).

Program Size: The sum of the sizes of the user programs in bytes. If there is a ladder logic program, add 11,000 bytes to account for internal memory usage that is not included in the user program memory displayed by the programmer. The 11,000 bytes is an approximate number typical for most LD programs. If a more accurate number is desired, use the file size of the _main.dec file instead of the 11,000. The _main.dec file can be found on disk inside of your folder’s directory structure.

Sweep Time: The sweep time in milliseconds when the number of checksum words is set to zero and the Background Window timer is set to zero.

Maximum Completion Time: The amount of time in milliseconds that you want to have full coverage of these diagnostics. For example, 1 minute is 60,000ms.

TF: the number of milliseconds per byte of program checksummed (see following table).

C: the total time in milliseconds needed to perform background diagnostics (see following table).

 

CGR772

CGR935

 

 

 

Milliseconds per byte of program

.0064 ms/byte

.0014 ms/byte

checksummed (F)

 

 

 

 

 

Time to perform Background Diagnostics (C)

3479 ms

376 ms

GFK-1527A

Chapter 4 Normal Operation

4-19

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Contents GE Fanuc Automation GFL-002 Preface Content of This ManualRelated 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 CPU780Redundancy CPUs as Compared to Other Series 90-70 CPUs Features not Available with Redundancy CPUsDifferences in Operation for Redundancy CPUs Redundant Racks Enhanced Redundancy CPU ModuleRedundancy Communications Module Systems for Enhanced Hot Standby CPU RedundancyLocal I/O Genius I/OCable Connections Enhanced Hot Standby CPU Redundancy System with Local I/O Local I/0 Can beGHS Control Strategy Control StrategiesGDB Control Strategy Output Control with GHS Basic Enhanced Hot Standby OperationOutput 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 ExternalOn-Line Repair Online ProgrammingDuplex CPU Redundancy System Components For Installation InstructionsSystem Racks Features Redundancy CPUCPU Architecture Watchdog TimerExpansion Memory Board Battery Connectors CPU FeaturesMemory Protect Keyswitch CPU LEDsCPU Mode Switch PortRedundancy Communications Module Unit Select PushbuttonConnector RCM Status LedsBus Transmitter Module ConnectorsBus Transmitter Module Status LEDs Cables and Termination Bus Receiver ModuleBus 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 Validating the Backup PLCs Input Scan Backup Qualification with Svcreq #43Validating the Backup PLCs Logic Solution Switching Control to the Backup Unit Switching TimesRUN Disabled Mode for GHS Control Strategy RUN Disabled ModeExample 1 Role switches allowed on both units Example 3 Role switches not allowed on either unit Example 2 Role switches allowed on both unitsExample 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 RacksRedundancy Communications Module and Cables Central Processor UnitRedundancy 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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