Pepperl+Fuchs LB Series User Manual

LB Remote I/O System
Installation
2018-07
43
3.13 Redundancy
3.13.1 Basic Principles
Redundancy is used when it is necessary to guarantee operation of a remote I/O station
despite one or more components having failed.
To build a redundant system, use backplanes LB9022* and LB9029A and equip these with two
com units for com unit redundancy and three power supplies for power supply redundancy.
Two power supplies are sufficient to supply the entire backplane. The third power supply is a
redundant power supply that can compensate for the failure of another power supply.
It is possible to tell which com unit is active by looking at the operating mode LED. If the
operating mode LED is flashing, the com unit is active. If the operating mode LED is not lit, the
com unit is passive. For more information about the status LEDs, refer to the data sheet for the
relevant com unit in use.
As a general rule, a distinction is made between media redundancy and application
redundancy. Com units can be set to media redundancy or application redundancy using the
configuration software. For more information, refer to the software manual for the com unit
used.
3.13.2 Media Redundancy
Media redundancy is when the master communicates with a com unit via a voter and a
redundant fieldbus cable. The com unit that communicates with the master is active and
controls the I/O module on the backplane. The second com unit is passive and reads the data
traffic on the backplane.
If the active com unit fails, the passive com unit automatically takes on the configuration of the
com unit that was previously active. When there is media redundancy, switching between the
com units is independent of the fieldbus cable used.
Figure 3.14 Line redundancy
If the master is also redundant, this is known as extended media redundancy.
Figure 3.15 Extended media redundancy
Note!
Note that both com units in a redundant system must have the same firmware.
Redundant
Fieldbus
Voter
Master
Fieldbus
Backplane
Com
Unit
Red. Com
Unit
Voter
Red.
Master
Redundant
Fieldbus
Voter
Master
Fieldbus
Backplane
Com
Unit
Red. Com
Unit

Pepperl+Fuchs LB Series Specifications

General

Mounting	DIN Rail
Zone	Zone 1, Zone 2
Power Supply	24 V DC
Protection Class	IP20
System Type	Remote I/O System
Communication Protocols	PROFIBUS DP
I/O Modules	Analog, Digital
Signal Type	Analog, Digital
Number of Channels	Varies by module
Intrinsic Safety	Yes
Isolation	Channel to channel, channel to system
Output Current	Varies by module (e.g., 0.5 A, 2 A)
Connection Type	Screw terminals
Dimensions	Varies by module
Weight	Varies by module
Temperature Range	-20 ... 60 °C (-4 ... 140 °F)