State Industries GFK-0827 manual Words per Sweep =

Page 80

4

Background User Checksum and Background Window

Timing Instructions

The following information is provided to allow you to guarantee full coverage of the number of program words verified by the User Program Checksum per sweep and the Background Window Diagnostics within a certain amount of time. It is important to understand that the more checksums performed and the larger the background window, the longer the sweep will take. For example setting the number of words to checksum to 176 will add 2.8 ms to each sweep.

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

(program size ⎟2) x (sweep time) x maximum completion time

Words per Sweep =

[max. completion time ± (program size x F)] x max. completion time ± C) ± (C x F x program size)

Where:

HWords per Sweep: The number of words to set in the PLC Configuration to be checksumed each sweep. This number must be a multiple of 8.

HProgram Size: The size of the user program in bytes. You can get this from the Logicmaster 90 PLC Memory Usage screen, which is accessed by pressing the status softkey (F3) from the Programmer Main menu, then the plcmem softkey (F5). Add the ºUSER PROGRAMº size on this screen to 10566 (this accounts for internal memory usage not added to the user program memory.

HSweep Time: The sweep time in milliseconds of the user program with checksums and background window turned off. You can get this from the Logicmaster 90 status line on any screen.

HMaximum Completion Time: The amount of time in milliseconds that you want to have full coverage of background diagnostics.

HF: A constant that represents milliseconds per byte of user program checksumed. This constant is dependent on the type of CPU module (that is CPUs with 80386 microprocessors are faster than CPUs with 80186 microprocessors). This constant is 0.008 ms/byte for the CPU 780.

HC: A constant with units in milliseconds, which is also dependent on the type of CPU. For the CPU 780 it is 4480 ms.

Following is an example of calculating the Words per Sweep, using the following data: User program Size = 89434 bytes

Program Size =User program Size + 10566 = 89434 + 10566 = 100000 bytes Sweep Time = 100 ms

Max. Completion Time = 120000 ms (2 minutes)

100000 ⎟2 x 100 x 120000

Words per Sweep =

[120000 ± 100000 x 0.008] x (120000 ± 4480) ± (4480 x 0.008 x 100000)

Words per Sweep = 174

You should round this answer (174) up to the nearest number divisible by 8 (8, 16, 24, etc.) which is 176 since Logicmaster 90 only accepts numbers divisible by 8. Next use this number in the following formula to determine how long to set the background window time.

Background Window Time =

C x (sweep time + words per sweep x F x 2)

(maximum completion time ± C)

GFK-0827

Chapter 4 Operation

69

Page 79 Page 81
Image 80
Page 79 Page 81
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 ProductSystems for Hot Standby CPU Redundancy Systems Genius I/O SystemLocal I/O System Cable ConnectionsBasic Hot Standby Operation Control StrategySynchronized Hot Standby CPU Redundancy System Configuration Redundancy CPU Module Redundancy Communications ModuleBumpless Switching Switch to Backup Unit TimeSynchronized CPUs 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 SystemBasic Redundancy System Setup Logicmaster 90 ConfigurationSystem 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 Power Supply RacksCentral Processor Unit 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
Top Page Image Contents