PM861/PM864/TP830 Processor Unit – Redundancy
Section 1 Introduction
36
3BSE 027 941 R301
PM861/PM864/TP830 Processor Unit – Redundancy
Processor unit redundancy is available. In this case, the controller contains two
processor units, each including memory for system and application software. One
unit is acting as primary, the other is backup (hot stand-by). The primary processor
unit controls the process. The backup stands by to take over in case of a fault in the
primary. The changeover is done bumplessly and in less than 10 ms. During the
changeover, the process outputs are frozen.
Following a changeover, the system operates as a system without redundancy with
only one processor unit in operation. You can replace the malfunctioning processor
unit while the system is running. After the replacement is carried out, the system
once again has a redundant processor unit.
If an error arises in the backup unit, you can also replace the backup unit while the
system is running.
Errors which occur in the backup unit can never affect the primary unit’s operation.
The primary unit and the backup unit are logically separated from one another.
Hardware errors in the primary processor unit cause the system to perform a correct
changeover. These hardware errors are "single errors".
The application programming and the communication are totally unaffected by the
redundancy.
The serial port, COM3 on the baseplate TP830, can not be used in redundant CPU
configuration.
The PM861/PM864 has an RCU Link Connector for connecting the RCU Link
Cable (see
on page 29). In a redundant system the two processor units are
linked together with the RCU Link Cable. Both processor units are also connected
to the same CEX-bus and either of the two can control the expansion units
(see
S800 I/O units are connected to the two CPUs via the optical ModuleBus and two
TB840 cluster modems on each S800 I/O cluster (see
on page 98). The
built-in electrical ModuleBus on the TP830 baseplate cannot be used for connecting
S800 I/O in a redundant system.
Summary of Contents for AC 800M
Page 1: ...ControlIT AC 800M Version 2 1 Controller Hardware Hardware and Operation...
Page 2: ......
Page 3: ...Controller Hardware Hardware and Operation ControlIT AC 800M Version 2 1...
Page 10: ...7DEOH RI RQWHQWV 10 3BSE 027 941 R301...
Page 20: ...Related Documentation About This Book 20 3BSE 027 941 R301...
Page 26: ...Operating Environment Safety Summary 26 3BSE 027 941 R301...
Page 42: ...Product Release History Section 1 Introduction 42 3BSE 027 941 R301...
Page 108: ...Powering from an External 24 V DC Source Section 3 Configuration 108 3BSE 027 941 R301...
Page 118: ...Verification of Redundant CPU Section 4 Operation 118 3BSE 027 941 R301...
Page 212: ...Low Voltage Directive LVD Appendix D Directive Considerations 212 3BSE 027 941 R301...
Page 214: ...Hazardous Location Approval Appendix E Standards 214 3BSE 027 941 R301...
Page 228: ...QGH 228 3BSE 027 941 R301...
Page 229: ......
