GE Fanuc Automation Programmable Control Products Series 90™-70 Enhanced Hot Standby CPU Redundancy User's Guide GFK-1527A May 2000
GFL-002 Warnings, Cautions, and Notes as Used in this Publication Warning Warning notices are used in this publication to emphasize that hazardous voltages, currents, temperatures, or other conditions that could cause personal injury exist in this equipment or may be associated with its use. In situations where inattention could cause either personal injury or damage to equipment, a Warning notice is used. Caution Caution notices are used where equipment might be damaged if care is not taken.
Preface This manual is a reference to the hardware components, configuration and operation of Enhanced Hot Standby CPU Redundancy for the Series 90-70 Programmable Logic Controller. This revision adds information about new redundancy CPUs IC697CGR772 and IC697CGR935, as well as new features available with Release 7.85 of the product. Also, corrections have been made where necessary.
Preface Logicmaster 90-70 Programming Software User's Manual (GFK-0263). A programming software user's manual for system operators and others using the Logicmaster 90-70 software to program, configure, monitor, or control a Series 90-70 PLC system. Series 90-70 PLC CPU Instruction Set Reference Manual (GFK-0265). Reference manual which describes operation, fault handling, and programming instructions for the Series 90-70 PLC. Series 90-70 System Manual for Control Software Users (GFK-1192).
Contents Chapter 1 Introduction..................................................................................................... 1-1 Enhanced Hot Standby CPU Redundancy ..................................................................... 1-2 Features of Enhanced Hot Standby CPU Redundancy ................................................... 1-3 Using the Redundancy CPU for Non-Redundant Operation .................................... 1-3 Compatibility with CPU780 ........................................
Contents Port 2.................................................................................................................... 2-5 Port 3.................................................................................................................... 2-5 Redundancy Communications Module.......................................................................... 2-6 Unit Select Pushbutton .......................................................................................... 2-6 Connector .........
Contents Fail Wait Time...................................................................................................... 4-8 Programming a Data Transfer from Backup Unit to Active Unit.................................. 4-10 Data Transfer Example................................................................................. 4-10 Disabling Data Transfer Copy in Backup Unit (SVCREQ #43) ................................... 4-11 Command Block for SVCREQ #43 ..............................................
Contents Fault Actions in a CPU Redundancy System................................................................. 5-7 Configurable Faults............................................................................................... 5-8 Non-Configurable Fault Group.............................................................................. 5-9 Fatal Faults on Both Units in the Same Sweep ....................................................... 5-9 On-Line Repair...........................................
Chapter Introduction 1 This chapter introduces the method of CPU Redundancy for the Series 90-70 Programmable Logic Controller, which is referred to as Enhanced Hot Standby CPU Redundancy.
1 Enhanced Hot Standby CPU Redundancy CPU Redundancy allows a critical application or process to continue operating if a failure occurs in any single component. An Enhanced Hot Standby CPU Redundancy system consists of two CPUs connected to one or more Genius I/O networks. One PLC is the Primary PLC and the other is the Secondary PLC.
1 Features of Enhanced Hot Standby CPU Redundancy Bumpless switching Synchronized CPUs 4.7 ms (CGR935), 5.
1 Redundancy CPUs as Compared to Other Series 90-70 CPUs The Redundancy CPU has several differences in operation compared to other Series 90-70 CPUs. Features not Available with Redundancy CPUs The following features are not available: I/O Interrupts: This includes the single edge triggered interrupts from the discrete input modules, the high alarm and low alarm interrupts from the analog input modules, and interrupts from third party VME modules.
1 Components of the Enhanced Hot Standby Redundancy System Enhanced Redundancy CPU Module To utilize the features described in this manual, an Enhanced Redundancy CPU Module (IC697CGR935 or IC697CGR772) must be installed rack 0, slot 1 of both the Primary and Secondary PLCs. Features of the redundancy CPU that are different from conventional CPUS are listed on the previous page.
1 Genius I/O The redundant portion of the system is based on Genius I/O. A system using standard Series 90-70 racks can have multiple Genius I/O bus networks. A system using the ½ slot redundant racks may have only one bus in the CPU rack. Any Genius device can be placed on the bus (Genius blocks, Field Control, Remote I/O Scanner, VersaMax I/O, etc.). The Genius devices are under control of the active unit in the Redundancy system.
1 Enhanced Hot Standby CPU Redundancy System with Local I/O The following illustration is an example of an Enhanced Hot Standby CPU Redundancy system with Local I/O in standard Series 90-70 expansion racks.
1 Control Strategies There are two different Control Strategies for Enhanced Hot Standby CPU Redundancy: GHS and GDB.
1 Basic Enhanced Hot Standby Operation In an Enhanced Hot Standby CPU Redundant system, Genius I/O Blocks are normally configured for Hot Standby operation. Genius I/O Blocks can also be configured for the less frequently used Duplex operation, but only with the GDB Control Strategy. When configured for Hot Standby operation, the blocks must choose between outputs from the Genius Bus Controller at serial bus address 31 and the Genius Bus Controller at serial bus address 30.
1 Basic CPU Redundancy Setups There are three basic CPU Redundancy setups: Single Bus with Preferred Master Single Bus with Floating Master Dual Bus with Floating Master Single Bus with Preferred Master: GHS Control Strategy This type of system uses a single Genius bus with bus controllers in each PLC. The Primary Unit is always chosen as the active unit when the units initially synchronize.
1 Single Bus with Floating Master: GDB Control Strategy This type of system also uses a single bus with bus controllers in each PLC. However, no switchover occurs on initial synchronization to make the Primary Unit the active unit. Secondary Unit Primary Unit PC B R G SP T C B U M M C PC B R G SP T C B U M M C 30 31 Critical Data + Redundant Outputs Transferred PS.............. CPU........... BTM............ RCM........... GBC............ BLOCK....... Power Supply.. Central Processor Unit.
1 Dual Bus with Floating Master: GDB Control Strategy This type of system uses dual buses with bus controllers in each PLC. No switchover occurs on initial synchronization to make the Primary Unit the Active Unit. Bus Switching Modules (BSMs) are required in accordance with the traditional configuration of a Dual Bus network. This option provides redundancy of both the PLC and the I/O bus.
1 Duplex CPU Redundancy Only discrete blocks (or Remote I/O Scanners with only discrete modules) can be configured for Duplex CPU Redundancy mode. Blocks or I/O Scanners configured for Duplex mode receive outputs from BOTH bus controllers 30 and 31, and compare them. If devices 30 and 31 agree on an output state, the output goes to that state. If devices 30 and 31 send different states for an output, the block or I/O Scanner defaults that output to its pre-selected Duplex Default State.
Chapter System Components 2 This chapter describes the hardware components for an Enhanced Hot Standby CPU Redundancy system. System Racks Redundancy CPU Redundancy Communications Module Bus Transmitter Module Bus Receiver Module Genius Bus Controller For Installation Instructions For detailed installation instructions for the Series 90-70 PLC, refer to GFK-0262, the Series 90-70 Programmable Controller Installation Manual.
2 Redundancy CPU The redundancy CPUs have been designed specifically for Series 90-70 Hot Standby CPU Redundancy applications. Features The Enhanced Hot Standby CPU supports floating point calculations, offers remote programmer keyswitch memory protection, and has seven status LEDs. Operation of the CPU may be controlled by the three-position RUN/STOP switch on the module, or remotely by an attached programmer.
2 CPU Architecture The CGR772 and CGR935 have an 80486DX4 microprocessor, on-board memory, and a dedicated VLSI processor for performing Boolean operations. The CGR772 and CGR935 interface to serial ports and the system bus. The microprocessor provides all fundamental sweep and operation control, plus execution of non-Boolean functions. Boolean functions are handled by the dedicated VLSI, Boolean Coprocessor (BCP).
2 CPU Features Memory Protect Keyswitch Memory Protect Keyswitch LEDs The Memory Protect keyswitch can be used to manually lock program and configuration data from access by a remote programmer (serial or Ethernet). When the key is in the ON position, program and configuration data can only be changed by a programmer connected to the Bus Transmitter Module.
2 CPU Mode Switch The CPU Mode switch selects the operating mode of the CPU: RUN/ENABLED, RUN/DISABLED, or STOP. The CPU mode can also be controlled from the programmer. However, the CPU Mode switch position restricts the ability of the programmer to put the CPU into certain modes, as shown in the following table.
2 Redundancy Communications Module The Redundancy Communications Module (RCM), catalog number IC697RCM711 or IC687RCM711 (½ slot version), provides a communications path for sharing data between the two CPUs in the redundant system. In a synchronized system, I/O data is controlled by one unit (the active unit) but is shared between both units (active and backup units). An RCM must be in both the Primary PLC and the Secondary PLC. The RCM must reside in rack 0.
2 Connector LEDs BOARD OK LOCAL SYSTEM READY The top connector on the Redundancy Communications Module LOCAL SYSTEM ACTIVE REMOTE SYSTEM READY must be connected via an I/O cable to the last rack of the other REMOTE SYSTEM ACTIVE PLC. If no expansion rack is used, it is connected to the lower Unit Select connector on the Bus Transmitter Module of the other system. The Pushbutton I/O cable with built-in termination is available in three lengths: IC697CBL803, 3 feet (0.
2 Bus Transmitter Module A Bus Transmitter Module (BTM), catalog number IC697BEM713 or IC687BEM713 (½ slot version), must be in rack 0 of both the Primary PLC and the Secondary PLC in a Hot Standby CPU Redundancy system. The Bus Transmitter Module provides a path for Redundancy communications when connected to the Redundancy Communications Module as described previously. Each PLC in the redundancy system (Primary and Secondary) must have a BTM and an RCM in rack 0.
2 Bus Receiver Module The Bus Receiver Module (BRM), catalog number IC697BEM711, is the expansion rack interface to the I/O bus. The Bus Receiver Module connects to a Bus Transmitter Module in rack 0 or to a Bus Receiver Module in the previous rack via a parallel I/O bus cable. In a CPU Redundancy system with expansion racks, the last bus connection is to a Redundancy Communications Module, as explained previously.
2 Genius Bus Controller The Genius Bus Controller (IC697BEM731) interfaces the Series 90-70 PLC to a Genius I/O bus. The bus controller scans bus devices asynchronously and exchanges I/O data with the CPU once per scan. Location of GBCs and Blocks For dual bus Genius networks, the Genius bus controllers should be placed at the same end of the bus, as pictured below.
2 Single Bus Genius Networks When using single-bus Genius networks in a Hot Standby CPU Redundancy system, one Genius Bus Controller for the bus must be located in the Primary PLC and one in the Secondary PLC. There can be multiple Genius busses in the system. The bus controllers in the Primary PLC are assigned Serial Bus Address 31. The bus controllers in the Secondary PLC are assigned Serial Bus Address 30. Data from Serial Bus Address 31 in the Primary PLC is the "preferred" data.
2 30. Data from Serial Bus Address 31 in the Primary PLC is the "preferred" data. The GDB control strategy must be used and all redundant Genius outputs must be transferred from the active to the backup unit. Each dual bus can have up to 30 additional Genius devices connected to it. One Serial Bus Address must be reserved for a Hand-Held Monitor. Any type of Genius device can be connected to this bus.
Chapter Configuration Requirements 3 This chapter defines the special configuration requirements of an Enhanced Hot Standby CPU Redundancy system. Programmer Connection for Configuration In a Hot Standby CPU Redundancy system, one CPU is configured as the Primary CPU and the other as the Secondary CPU. The Primary Unit and the Secondary Unit must be configured separately. The programming device must be connected directly to either the Primary or the Secondary Unit to configure that unit.
3 Program Folders in Logicmaster 90 With the Logicmaster programming software, there must be different folders for each configuration. If the logic is identical for both PLCs, a third folder could be used for the logic and reference tables. This results in three folders for the system. Folder A - configuration for the Primary unit. Folder B - configuration for the Secondary unit. Folder C - logic and reference tables for both systems.
3 Configuring Shared I/O References Shared I/O data is transferred from the active CPU to the backup CPU each sweep. Reference addresses and ranges must be configured for the data to be transferred. There can be up to 20 Kbytes of input data (%I, %AI) and up to 28 Kbytes of output data (%Q, %AQ, %M, %R) transferred. Input references should be transferred to the backup unit if the program logic requires identical inputs for the two units.
3 Finding the Memory Available for Application Program Storage Shared I/O data is stored in the same memory as application program storage. To find the amount of memory available for application program(s), subtract the overall transfer data amount from the amount of memory (512K bytes for CGR772, 1024K bytes for CGR935) available for the application program.
3 Configuring the Redundancy CPU for Non-redundant Operation The Redundancy CPU can be used for both redundant and non-redundant applications. For nonredundant applications, do not configure Redundancy Communications Modules in the system. If a Bus Transmitter Module is configured set the Remote RCM Present parameter to NO. Keep all redundancy-related parameters in their default settings. Genius I/O in the non-redundant system can be configured for either no redundancy or externally paired.
3 Genius I/O Block Configuration Parameters When using the GHS Control Strategy, if a Genius Bus Controller is set to redundant, then all of its I/O blocks must also be set to redundant. When using the GDB Control Strategy, if a Genius Bus Controller is set to redundant, then all of its I/O blocks are normally configured as redundant. 3-6 If a Genius Bus Controller is set to non-redundant, all of its I/O blocks must also be set to nonredundant.
Chapter Normal Operation 4 This chapter discusses: GFK-1527A Powerup of a Redundant CPU Resynchronization of the Redundant CPU GHS Control Strategy GDB Control Strategy %S References for CPU Redundancy Scan Synchronization Switching Control to the Backup unit RUN Disabled Mode Background User Checksum and Background Window Timing Instructions Miscellaneous Operation Information Genius Bus Controller Switching Ethernet Global Data in a Redundancy CPU 4-1
4 Powerup of a Redundant CPU When a redundant CPU is powered up, it performs a complete hardware diagnostic check and a complete check of the application program and configuration parameters. This causes the powerup time of a redundant CPU to be significantly longer than the normal powerup time of a nonredundant CPU. If the Primary and Secondary systems power up together each CPU will recognize this fact so that the Primary system will become the active and the Secondary system the backup.
4 Incompatible Configurations When two units have incompatible configurations stored (for example, both units configured for PRIMARY or differing blocks for data transfer), then only one of the units can go to RUN mode. If the other unit attempts to go to RUN mode or both units attempt to go to RUN mode at the same time, a FATAL incompatible configuration fault will be logged.
4 FST_EXE references for program blocks with the same name are transferred from the active to the backup CPU. The result is that if one CPU is already in Run mode and the other is transitioning to Run mode, the FST_SCN and matching FST_EXE bits are not set on the first scan of the transitioning unit. These bits are considered system bits and set if one unit comes up alone, or if both units come up together. No transfer of data occurs at this point if both units are transitioning to Run mode.
4 portion of the bus between the BSM and the blocks) result in loss of the blocks downstream from the failure on that bus stub. Bus failures in single bus networks result in loss of the blocks downstream from the bus failure. When using the GDB control strategy, the user is required to transfer all redundant Genius outputs to the backup unit so that both units drive the same output values. %S References for CPU Redundancy %S33 through %S39 and %SB18 reflect the status of the Redundancy units.
4 Scan Synchronization The figure below shows the sweep components for the active and the backup CPUs.
4 The Start of Sweep Time message transfer repeatedly coordinates the elapsed time clocks (upon which timers are based) in the redundant CPUs. The system time is continuous as long as one of the two systems is running. When a switchover occurs, the same time continues to be kept in the new active unit. Output Data Transfer to the Backup Unit After the initial data transfer, both CPUs operate independently until the end of the program logic solution.
4 Data Transfer Time When a system is synchronized, there are additions to the sweep time (compared to a similar nonredundant CPU model) for synchronization activities and for transferring data from the one unit to the other. The amount of time for transferring data depends on the type and amount of data transferred. These additions are shown in the following tables.
4 The configured Fail Wait time for the system must be based on the maximum expected or allowable difference in the two CPUs reaching a synchronization point. For example, if one CPU might spend 20ms in the communications phase of the sweep and the other unit might spend 95ms in communications in the same sweep, the Fail Wait time must be set to at least 80ms (80 > 95 -20) to prevent accidental loss of synchronization.
4 Programming a Data Transfer from Backup Unit to Active Unit Optionally, the program logic can be used in both CPUs to transfer eight bytes (4 registers) of data from the backup unit to the active unit before the next logic solution. To initiate this transfer, the backup unit executes SVCREQ #27 (Write to Reverse Transfer Area). This command copies eight bytes of data from the reference in the backup unit specified by the PARM parameter. Note that SVCREQ #27 only works when its CPU is the backup unit.
4 Disabling Data Transfer Copy in Backup Unit (SVCREQ #43) Service Request function block #43 can be used on the backup to allow the backup unit to bypass the copy of the shared I/O data from the active unit. This function can be used to help determine if the active and backup CPUs are arriving at the same results. This function is useful only when issued in the backup CPU. It is ignored if issued when the units are not synchronized, or if it is issued in the active unit.
4 A fault is logged the first time SVCREQ #43 is used as a warning that the PLCs are not completely synchronized. The reverse data transfer, if any, is unaffected by this function block. Enabling logic should be used with SVCREQ #43. A contact with a non-transferred reference should be part of this enabling logic. That will allow the function block to be turned on/off directly without being overwritten by the value from the active unit.
4 Example In the following example, when %M00035 is on, the input and output copies are disabled. %M00035 %T00041 MOVE_ INT CONST 00000 IN Q LEN 00001 MOVE_ INT %L00001 CONST 00001 IN Q LEN 00001 SVC_ REQ %L00002 CONST 00043 %L00001 FNC PARM Backup Qualification with SVCREQ #43 Service Request function block #43 can be used to help determine if the backup PLC unit is collecting inputs properly (that is, validate the input scan).
4 Switching Control to the Backup Unit Control switches from the active unit to the backup unit if: 1. 2. 3. 4. the active unit has a failure; the pushbutton switch on the Redundancy Communications Module is pressed; a switch is commanded from the application program. the active unit is placed in Stop mode or powered off. Switching Times The amount of time needed to switch control from the active unit to the backup unit depends on the reason for the switch.
4 RUN Disabled Mode RUN/DISABLED mode causes all physical outputs to go to their default state in that PLC. Inputs are still scanned and logic is solved. A CPU in RUN/DISABLED mode may be the active unit. RUN Disabled Mode for GHS Control Strategy There are several guidelines for using RUN/DISABLED mode when using the GHS Control Strategy. 1.
4 Example 2: Role switches allowed on both units The Secondary unit drives the outputs in this example.
4 Example 5: Role switches allowed on both units Secondary Unit Active Note: Secondary unit active is not a recommended mode of operation when using the GHS Control Strategy.
4 Example 8: Invalid The following situation is not valid. If detected, the units switch roles automatically and behave as in Example 3 above. Primary Unit Role Operating Mode Secondary Unit Backup Active RUN/ENABLED RUN/DISABLED RUN Disabled Mode for GDB Control Strategy The following guidelines apply to using RUN/DISABLED mode with the GDB Control Strategy. 1.
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).
4 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.
4 Miscellaneous Operation Information Timer and PID Function Blocks Timer and PID function blocks remain in lock step between two synchronized units provided: A. Enabling logic is identical on both units. This includes power flow, frequency of calling sub-block, and so forth. B. The sub-block in which the function block occurs has the same name in both units. Note that _MAIN is always common. C.
4 a scan set that is scanned every other sweep (that is, PERIOD=2), then the Primary CPU might scan its scan set in one sweep and the Secondary CPU scan its scan set in the next. Use of non-default scan sets can cause variance in the time the units get to the rendezvous points. This should be considered when determining the failwait time. C Debugger The Embedded C debugger may be used for debugging Standalone C programs and EXE blocks.
4 Genius Bus Controller Switching Genius Bus Controllers stop sending outputs to Genius I/O blocks when no output data has been received from the PLC CPU for a period equal to two times the configured watchdog timeout. If the CPU in the Primary Unit becomes inoperative in an uncontrolled fashion (for example, because of a power failure), the Genius Bus Controllers detect this within twice the watchdog setting, and stop sending outputs to the Genius blocks.
4 Ethernet Global Data in a Redundancy CPU Ethernet Global Data is enhanced to provide optimal use with Redundancy CPUs. Configuration of Ethernet Global Data requires the use of Control Programming software, release 2.1 or later. Ethernet Global Data Consumption Either or both of the PLC units in a synchronized system can consume Ethernet Global Data. Consumption by individual units requires separate Ethernet Global Data configurations for the two units and therefore separate folders.
4 Ethernet Global Data Production When the two units of a CPU Redundancy system are synchronized, Ethernet Global Data exchanges are produced only by the active unit. This reduces the amount of traffic on the Ethernet network and simplifies the handling of the exchange by the consumer. In particular, the consumer is able to consume the exchanges in the same way as for exchanges from non-redundant systems.
Chapter 5 Fault Detection This chapter describes how faults are handled in a Redundancy system.
5 2. If an expansion rack fails after a unit becomes a stand-alone unit, a diagnostic fault will be logged on that unit but the unit will stay in RUN mode and continue to control the process. 3. If after the above situation occurs, the other unit transitions to RUN, the unit with the failed expansion rack will stay in RUN mode and may, depending on the configuration, remain in control of the process.
5 PLC Fault Table Messages for Redundancy The following table lists messages, descriptions, and corrective actions for error codes associated with the redundancy fault group. These error codes can be viewed by selecting Ctrl-F on the corresponding redundancy fault (in Logicmaster 90-70) or double-click on the corresponding fault (in Control). The entire fault data (including these error codes) can also be accessed with a SVC_REQ and other applications that communicate with the CPU.
5 Error Code Message Fault Description Corrective Action 9 Primary and Secondary Units are Incompatible The local unit cannot be placed in RUN mode when its redundancy configuration is incompatible with the remote unit. This error is logged when (1) Store of an incompatible configuration is attempted and (2) attempting to synchronize with an incompatible configuration.
5 Fault Response The Enhanced Hot Standby CPU Redundancy system detects and reports failures of all critical components so that appropriate control actions may be taken. All components that acquire or distribute I/O data or that are involved in execution of the control logic solution are considered critical components. In a Redundancy system, fault actions are not configurable as they are in a non-redundancy system. A FATAL fault in the active unit causes a switch of control to the backup unit.
5 Faulting RCMs, Losing Links, and Terminating Communications There are distinct differences between losing a redundant communications link and faulting an RCM. Faulting the Redundancy Communications Module Faulting the Redundancy Communications Module occurs only when a hardware-related failure such as a parity error or VME bus error exists. The following actions are taken when a Redundancy Communications Module is faulted: 1. Loss of Module fault is logged in the PLC Fault Table. 2.
5 The following actions are taken when a link has timed out. 1. Link Timeout fault is logged in the PLC Fault Table. 2. The OK and Local LEDs on the Redundancy Communications Module in the RCM to BTM link that failed continue to be maintained (that is, they will stay ON and the Local LEDs reflect the state of the Local unit) but the Remote LEDS are turned OFF. The LEDs on the other RCM continue to be updated as long as that RCM is OK. 3. The module fault contact is set.
5 Configurable Faults The table below shows the configurable faults and their fault action defaults. There are three fault actions: Fatal, Non-Fatal, and Conditionally Fatal. Fatal always stops the PLC, Non-Fatal never stops the PLC and Conditionally Fatal stops the PLC depending on other information in the fault. Note that Non-Fatal and Diagnostic have the same meaning.
5 Non-Configurable Fault Group The table below shows the non-configurable faults and their fault action defaults. Fault Group Table Type Description Fault Actions Not Synchronized Synchronized SYS_BUS_FAIL PLC System bus failure. Fatal Fatal NO_USER_PRG PLC No User's Program on Power-up. Non-Fatal Non-Fatal BAD_USER_RAM PLC Corrupted User RAM detected on Power-up. Fatal Fatal WIND_CMPL_FAIL PLC Window Completion Failure in Constant Sweep Mode (i.e.
5 On-Line Repair With a Hot Standby CPU Redundancy system, most system component failures can be repaired by replacing the failed component while the system is online. These online repair procedures are possible because of the role-switching capability of the units in the system. Status of the Primary and Secondary Units is determined by observing the LEDs on the Redundancy Communications Module.
5 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.
5 In the unlikely event that a rack failure does occur and is correctly diagnosed, the rack can be replaced with power removed from the system. When the rack is replaced and power restored to the system, the CPU will obtain synchronization with the active system and either take control or become the backup CPU. Central Processor Unit If the redundancy CPU fails, the OK light on the CPU will turn off or blink. In addition, fault information will be available in the Fault Table of one or both CPUs.
5 Bus Transmitter Module A fault in the Bus Transmitter Module is treated just like a fault in the Redundancy Communications Module. It is only fatal if the fault prevents communications to any expansion racks within the system. Failure of the Bus Transmitter Module may not easily be distinguished from a Redundancy Communications cable failure or even an RCM failure. However, most failure modes of the Bus Transmitter Module can be isolated to the BTM.
5 Dual Bus Networks For dual bus Genius networks, a single trunk cable failure will result in the blocks downstream from the failure switching to the other Genius bus. Since both busses are attached to the same Genius blocks no loss of inputs or outputs will result. Failures in bus stubs (the portion from a BSM to its associated blocks) result in the loss of the blocks on that bus stub that are downstream from the failure. These blocks will be lost for both the active and the backup unit.
Appendix Cabling Information A IC690CBL714A Multi-drop Cable Purpose To interconnect Series 90-70 Redundant PLCs in a multi-drop serial communications arrangement. Specifications GFK-1527A Connector A: DB15F, 15-pin female connector with M3 latchblocks Connectors B and C: DB15M, 15-pin right angle, male connector with spring clips Wire: Cable consists of three individually shielded pairs of 22-gauge stranded conductors. equivalent to Belden #8777.
A Connector B Connector C Connector A Pin 1 M3 Latching Blocks (2) Pin 1 M3 pan head screws (2). Screws must not protrude through the end of the Latching Blocks. Figure A-1.
A Connector A, 15-pin Female, to other CPU or Adapter N.C. 9 6 8 Connector B, 15-pin male, to CPU SNP Port 14 15 5 5 7 7 10 10 11 11 12 12 13 13 6 8 14 15 9 N.C. 7 10 11 12 NOTE: Trim all drain wires flush with the jacket. 13 9 6 8 14 15 N.C. 5 Connector C, 15-pin male, to next CPU or final term. Figure A-2.
Index different for redundancy CPUs, 1-4 % %S references OVR_PRE not available with Redundancy CPUs, 1-4 Cable multi-drop, A-1 Checksum, 4-19 Checksum, program memory, 2-3 Communications terminating, 5-6 A Active unit defined, 1-1 Appendix A IC690CBL714A Multi-drop Cable, A-1 B Background Window time, 4-19, 4-20, 4-22 different for redundancy CPUs, 1-4 Backup CPU validating the logic solution, 4-13 Backup Unit defined, 1-1 switching control to, 4-14 commanding from program, 4-14 switching times, 4-
Index E Enhanced Hot Standby CPU Redundancy basic operation, 1-9 CPU features, 1-3 CPU version, 1-3 defined, 1-2 required modules, 1-2 output control, 1-9 output data transfer not necessary, 2-11 Run disabled mode, 4-15 summarized, 1-8 H Hot Standby defined, 1-1 Error checking, 2-3 Ethernet controller I configuring communications window, 3-4 Ethernet Global Data enhanced for redundancy CPUs, 1-4 in a Redundancy system, 4-24 Event-triggered programs not available with Redundancy CPUs, 1-4 F I/O sca
Index specifications, A-1 wiring diagram, A-3 Multiple I/O scan sets, 4-21 N Non configurable faults, 5-9 Non redundant operation, 1-3 configuring, 3-5 O Online programming, 1-13 Online repair, 1-13 description, 5-10 Output control, 1-9 Output data transfer, 4-6 Outputs disabled, 2-5 Outputs enabled, 2-5 OVR_PRE reference not available with Redundancy CPUs, 1-4 P Periodic programs not available with Redundancy CPUs, 1-4 PID function blocks, 4-21 Power supply replacement, 5-11 Redundancy Communication
Index Stop mode, 2-5 Stop to Run mode transition, 4-22 different for redundancy CPUs, 1-4 SVCREQ 26 role switch from program, 4-14 SVCREQ 27 Write to reverse transfer area, 4-10 SVCREQ 28 Read from reverse transfer area, 4-10 SVCREQ 43 using for backup qualification, 4-13 Sweep time, 4-20 Sweep time synchronization, 4-6 Synchronization scan, 4-6 Synchronized defined, 1-1 System Communications Window, 3-4 T Termination bus, 5-11 Timed contacts, 4-21 Timed programs not available with Redundancy CPUs,
