Chapter 1PLC3 Programmable Controller Backup SystemsUser Manual
Choosing a Backup ConfigurationChapter 11-3Primary processor - the processor that is controlling outputs. Whenswitchover to the backup processor occur
Programming TechniquesChapter 55-19When you select backup, you assign the same Data Highway or DataHighway Plus station number to both the scanner mod
Programming TechniquesChapter 55-20When you do not select backup, you assign a unique Data Highway (0008to 3768) or Data Highway Plus (008 to 778) sta
Programming TechniquesChapter 55-21Figure 5.7Sending a Message at Switchover| B1:0 S0:3 +MSG–––––––––––––––––––––––––+|
Programming TechniquesChapter 55-22another station on the Data Highway isinitiating a messagepossibly neither of the processors will respond to themes
Programming TechniquesChapter 55-23for the primary and backup processors. Then, place executable instructionsabove the rung and disallowed instruction
Chapter 66-1Diagnosing FaultsThis chapter describes how to diagnose faults in a PLC-3 backup systemusing: status indicators on the front panels of pr
Diagnosing FaultsChapter 66-2Now the backup processor is controlling outputs. If the backup processorattempts to execute the same logic rung that caus
Diagnosing FaultsChapter 66-3Figure 6.1Processor Front Panel10921PROCESSOROUTPUTSPROGRAMACCESSTable 6.AStatus Indicators for Primary Processor Indicat
Diagnosing FaultsChapter 66-4Table 6.BStatus Indicators for Backup Processor Indicator Status DescriptionPROCESSOR GREEN Backup processor is active (n
Diagnosing FaultsChapter 66-5Figure 6.2Indicator Locations for 1775S4 and 1775SR Scanner ModulesPASS and FAIL indicatorsThumbwheel switchI/O channel
Choosing a Backup ConfigurationChapter 11-4There are two backup configurations: scanner backup (Figure 1.2) which uses only I/O scanner modules MX bac
Diagnosing FaultsChapter 66-6Figure 6.4Indicator Locations for 1775MX Memory Communication ModulePASS and FAIL indicatorsStatus indicators1775 - MXSc
Diagnosing FaultsChapter 66-7Table 6.EData Highway/Data Highway Plus Status Indicators for 1775S5, SR5Scanner ModulesIndicator Status DescriptionXMT
Diagnosing FaultsChapter 66-8Diagnosing Faults with Status Word BitsAnother method of diagnosing faults is to examine the contents of statuswords in t
Diagnosing FaultsChapter 66-9Creating the Fault RoutineThe fault routine requires two rungs; one rung as the first rung in themain ladder program me
Diagnosing FaultsChapter 66-10Figure 6.5Main Routine (RM0) Rung S0:3 + XOR –––––––––––––––+ + XOR –––––––––––––––+ + XOR ––––––
Diagnosing FaultsChapter 66-11|| +–––––––––––––––––––––+| 10988I
Diagnosing FaultsChapter 66-12Keep the following points in mind when you use the fault routine in yourladder program. the rung in the main routine m
Diagnosing FaultsChapter 66-13Figure 6.7Major Fault BitsStack faultDeactiveBackup cable faultBad addressBad instructionConfiguration faultMemory parit
Diagnosing FaultsChapter 66-14Table 6.J ResultsIf the Processor Detects: The 1775 - GA or 1775 - S4BProcedure Will Display:No fault NO FAULT DETECTEDA
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Choosing a Backup ConfigurationChapter 11-5How MX Backup WorksFigure 1.3 shows the implementation of MX backup. The scanner modulesstill control I/O c
Choosing a Backup ConfigurationChapter 11-6Selecting Scanner or MX BackupTable 1.A and Table 1.B summarize the attributes of scanner backup andMX back
Choosing a Backup ConfigurationChapter 11-7The three methods of switching control of outputs from the primary to thebackup processor are: automatic s
Choosing a Backup ConfigurationChapter 11-8SwitchoverMethod:Attributes:ManualSwitchover When the primary processor faults, the system shuts down as t
Chapter 22-1Installing a Backup SystemThis chapter describes how to install PLC-3 and PLC-3/10 backupsystems. Specifically, it provides recommendation
Installing a Backup SystemChapter 22-2Important: The number one scanner module (thumbwheel set to 1) inboth primary and backup processors must be a 1
Installing a Backup SystemChapter 22-3Figure 2.1Connections for a PLC3 Backup System Using Scanner BackupTo EarthGroundBlueShieldClearTo otherI/O Cha
Installing a Backup SystemChapter 22-4Figure 2.2Connections for a PLC3 Backup System Using MX BackupTo EarthGroundBlueShieldClearTo otherI/O Chassisi
Because of the variety of uses for this product and because of thedifferences between solid-state products and electromechanical products,those respon
Installing a Backup SystemChapter 22-5Figure 2.3Connections for a PLC3/10 Backup System Using Scanner BackupTo EarthGroundBlueShieldClearTo otherI/O
Installing a Backup SystemChapter 22-6For a PLC-3 backup system, it is important to choose suitable powersupplies and make sure they are connected pro
Installing a Backup SystemChapter 22-7You must configure all I/O chassis for backup mode operation. Each I/Ochassis has eight switches. Two of the swi
Installing a Backup SystemChapter 22-8Setting Switch 2The processor restart lockout switch (switch 2) must be ON so the backupprocessor is capable of
Installing a Backup SystemChapter 22-92. Set all backup switches on all other scanner modules, if any arepresent, in both the primary and backup proce
Installing a Backup SystemChapter 22-10Figure 2.7Location of Backup Switches for 1775S5 and 1775SR5 ScannerModules18754Backup Switch atBottom Edge o
Installing a Backup SystemChapter 22-11Selecting a Backup CableChoose a backup cable for the switchover method desired. Table 2.C liststhe choices. Se
Installing a Backup SystemChapter 22-12Figure 2.10Backup Cable Wiring for Scanner Backup with Automatic Switchoverwith Controllable Switchback (Cat. N
Installing a Backup SystemChapter 22-13Figure 2.11Backup Cable Wiring for Manual Switchover (Cat. No. 1775CBB)1324561324561775CBBBACKUP CABLESCANNER
Installing a Backup SystemChapter 22-14Figure 2.12Connections for Scanner BackupPrimary Processor Backup ProcessorBackupcable(seetext)10395Application
Preface P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Manual Objectives P1. . . . . . . . . . . . . . . . . . .
Installing a Backup SystemChapter 22-15There are four I/O serial communication channels per scanner. Dependingon your system architecture, you can use
Installing a Backup SystemChapter 22-16Connecting I/O Communication ChannelsFigure 2.14 shows the connections when using I/O channel 1.Figure 2.14Conn
Installing a Backup SystemChapter 22-17If you designate another I/O channel for use as an I/O communicationchannel, replace the references to I/O chan
Installing a Backup SystemChapter 22-18Connecting an I/O Channel for PeertoPeer CommunicationAny I/O channel can be used for peer-to-peer communicat
Installing a Backup SystemChapter 22-19If you designate another I/O channel for use as a peer-to-peercommunication channel, replace the references to
Installing a Backup SystemChapter 22-208. If the last scanner is a 1775-S4A or 1775-SR scanner module, installa 1770-XT terminator to the I/O channel
Installing a Backup SystemChapter 22-21Connecting an I/O Channel for Backup CommunicationAny I/O channel can be used for backup communication. Figure
Installing a Backup SystemChapter 22-22If you designate another I/O channel for use as a backup communicationchannel, replace the references to I/O ch
Installing a Backup SystemChapter 22-23TerminatorsThe first and last physical device of each I/O channel requires a terminator.Use discrete terminator
Installing a Backup SystemChapter 22-24To implement MX backup you need two 1775-MX memorycommunication modules, one for the primary processor and ano
Table of ContentsiiProgramming Techniques 51. . . . . . . . . . . . . . . . . . . . . . . . . Chapter Objectives 51. . . . . . . . . . . . . . .
Installing a Backup SystemChapter 22-25To configure MX backup, do the following:1. Insert one memory communication module in the primary processorand
Chapter 33-1Operating a Backup SystemThis chapter describes how to operate a backup system. It recommendsprocedures for: starting up a backup system
Operating a Backup SystemChapter 33-2Startup Procedure Method 11. Turn off both the primary and backup processors, if they are notalready off.2. Turn
Operating a Backup SystemChapter 33-3Startup Procedure Method 21. Turn off both the primary and backup processors, if they are notalready off.2. Turn
Operating a Backup SystemChapter 33-4Figure 3.1Example Rung for Performing Memory Download at StartupDNMessageControlChannelDownload#B0:0E2.14.105ERB1
Operating a Backup SystemChapter 33-5To troubleshoot and/or repair a faulted processor, you may have todisconnect it.To disconnect a faulted processor
Operating a Backup SystemChapter 33-6Restart Procedure Method 11. Turn off both processors, if they are not already off.2. Reconnect the backup cable
Operating a Backup SystemChapter 33-7Restart Procedure Method 21. For the scanner backup configuration, place the switch, located in thebackup cable,
Chapter 44-1Using the 1775MXMemory Communication ModuleThis chapter describes how to use 1775-MX memory communicationmodules. Depending on your appli
Using the 1775MXMemory Communication ModuleChapter 44-2As shown in Table 4.A, you can control operation of memorycommunication modules by using: LIS
PrefaceP-1PrefaceThis manual shows you how to install, configure, and operate a backupsystem configured with PLC-3 or PLC-3/10 processors.In this man
Using the 1775MXMemory Communication ModuleChapter 44-3The following sections describe how to control memory communicationmodules by using LIST funct
Using the 1775MXMemory Communication ModuleChapter 44-4Figure 4.1LIST Menu for Primary and Backup ProcessorSYSTEM MODE1TEST MONITOR2*RUN MONITOR3PROG
Using the 1775MXMemory Communication ModuleChapter 44-5As shown in Table 4.B, a heading, which appears directly beneath thesystem identification, id
Using the 1775MXMemory Communication ModuleChapter 44-6The MCM OPERATION menu contains an entry for each LIST functionlisted in Table 4.D. These func
Using the 1775MXMemory Communication ModuleChapter 44-7Inactive CommandThe INACTIVE command lets you discontinue continuous data table andfile transf
Using the 1775MXMemory Communication ModuleChapter 44-8File Selection CommandTo specify a group of files, select the entry FILE SELECTION in theMCM O
Using the 1775MXMemory Communication ModuleChapter 44-9Important: Timers and counters cannot be separated into control, preset,and accumulated value
Using the 1775MXMemory Communication ModuleChapter 44-10Data Table Transfer CommandThe DATA TABLE XFER command lets you transfer all of the data tabl
Using the 1775MXMemory Communication ModuleChapter 44-11Memory Download CommandThe MEMORY DOWNLOAD command lets you transfer the entirecontents of th
Using the 1775MXMemory Communication ModuleChapter 44-12When you select the LOCK SYSTEM command, the memorycommunication module attempts to acquire t
PrefaceP-2Information that is especially important to note is identified by three labels: WARNING CAUTION ImportantWARNING: tells you of circumstances
Using the 1775MXMemory Communication ModuleChapter 44-13Enable Program Compare CommandThe ENABLE PROG COMP command lets you compare the ladderprogram
Using the 1775MXMemory Communication ModuleChapter 44-14Disable Program Compare CommandThe DISABLE PROG COMP command lets you disable the programcomp
Using the 1775MXMemory Communication ModuleChapter 44-15To enter the program compare limits, do the following:1. Select the command PROG COMP LIMITS
Using the 1775MXMemory Communication ModuleChapter 44-16Backup to Primary Data Transfer CommandThe BACKUP TO PRIMARY DATA TRANSFER command lets youen
Using the 1775MXMemory Communication ModuleChapter 44-17Operation of a memory communication module using message (MSG)instructions follows the same c
Using the 1775MXMemory Communication ModuleChapter 44-18Command DescriptionAbbreviationENABLE COMPARE E C The memory communication modulecompares a s
Using the 1775MXMemory Communication ModuleChapter 44-19See Table 4.H when creating a message instruction:Table 4.HMessage Instruction ComponentsEnte
Using the 1775MXMemory Communication ModuleChapter 44-20Start $ <file list> CommandThe START $<file list> command lets you transfer selec
Using the 1775MXMemory Communication ModuleChapter 44-21Table 4.IData Table Section SpecifiersData Table Selection SpecifierOutput Image OInput Image
Using the 1775MXMemory Communication ModuleChapter 44-22Figure 4.3Example Rung Illustrating Continuous File Transfer| B1:0 S0:3
PrefaceP-3For more information about components used with the PLC-3 backupsystem, see the publications listed in Table B.Table BRelated PublicationsPu
Using the 1775MXMemory Communication ModuleChapter 44-23Transfer $ <file list> CommandThe TRANSFER $<file list> command lets you transfer
Using the 1775MXMemory Communication ModuleChapter 44-24Start Data CommandThe START DATA command lets you transfer the entire contents of thedata tab
Using the 1775MXMemory Communication ModuleChapter 44-25Transfer Data CommandThe TRANSFER DATA command lets you transfer all sections of the datatabl
Using the 1775MXMemory Communication ModuleChapter 44-26Important: A memory download will not occur if:- the backup processor has insufficient memor
Using the 1775MXMemory Communication ModuleChapter 44-27You can check the status of each processor by looking at file 4, word 0 ofthe status section.
Using the 1775MXMemory Communication ModuleChapter 44-28Table 4.JEnable CompareIf the memory communication module: Then:completes the program compare
Using the 1775MXMemory Communication ModuleChapter 44-29For example, if the primary processor encountered a message instructioncontaining the command
Using the 1775MXMemory Communication ModuleChapter 44-30Disable Outputs CommandThe DISABLE OUTPUTS command lets you inhibit the backup processorfrom
Using the 1775MXMemory Communication ModuleChapter 44-31List Control CommandThe LIST CONTROL command lets you redirect control of a memorycommunicati
Using the 1775MXMemory Communication ModuleChapter 44-32Status On CommandThe STATUS ON command lets you enable data transfer from the backupprocessor
Chapter 11-1Choosing a Backup ConfigurationThe information in this chapter can help you: understand backup concepts evaluate different backup config
Using the 1775MXMemory Communication ModuleChapter 44-33Table 4.K is a list of error codes. These error codes may appear while youare controlling the
Using the 1775MXMemory Communication ModuleChapter 44-34If an error occurs, check the following: If the backup processor is powered down or faulted
Chapter 55-1Programming TechniquesThis chapter describes techniques you can use to program a PLC-3 backupsystem. In this chapter we describe: input c
Programming TechniquesChapter 55-2Using Repetition to Handle Short Input PulsesOne method of handling short input pulses is to repeat the rungs that r
Programming TechniquesChapter 55-3When using PLC-3 processors in a backup system configuration, programscans are not synchronized; and, although switc
Programming TechniquesChapter 55-4If the start pushbutton is pressed for too short a time, the input change maybe seen by the primary processor but no
Programming TechniquesChapter 55-5The force table is not transferred from the primary to the backup processorover any communication channel. Thus, if
Programming TechniquesChapter 55-6A PLC-3 backup system using memory communication modules requiresthe least amount of communication overhead. Data i
Programming TechniquesChapter 55-7Figure 5.3Programming for Block Transfer Inputs| Run/ BTR|| Backup Done|| S0:3 B200:12
Programming TechniquesChapter 55-8+––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––(MCR)–+||Other Program Rungs
Choosing a Backup ConfigurationChapter 11-2Why Use a Backup System?Backup is useful for applications in which an unexpected shutdown iscostly or other
Programming TechniquesChapter 55-9Another approach for reducing the amount of data transferred across abackup communication channel is to use Data Hig
Programming TechniquesChapter 55-10Backedup/Notbackedup BitThe backed-up/not-backed-up bit (file 0, word 3, bit 16) is set when optionswitch 2 on t
Programming TechniquesChapter 55-11The checksum is stored in file 0, word 5 and the checksum done bit isstored in file 0, word 4, bit 17 of the data t
Programming TechniquesChapter 55-12Refer to the PLC-3 Family Programmable Controller ProgrammingReference Manual (publication 1775-6.4.1) for detailed
Programming TechniquesChapter 55-131775MX Module CommunicationIf the PLC-3 backup system uses memory communication modules, thereare additional bits
Programming TechniquesChapter 55-14Important: Upon completing the program compare function, the memorycommunication module sets either bit 12 or 13 i
Programming TechniquesChapter 55-15Figure 5.6Program Compare Status Information for the Memory CommunicationModuleUnused value (always 0)User program
Programming TechniquesChapter 55-161775MX Module BackuptoPrimary Transfer Data WordsIn response to the BACKUP TO PRIMARY DATA TRANSFER in LISTor th
Programming TechniquesChapter 55-17Series A, Revision D (or later) 1775KA ModulesWhen using series A, revision D (or later) communication adaptermodu
Programming TechniquesChapter 55-18As long as the primary processor is controlling outputs, the stationaddress of the communication adapter module in
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