Operating Instructions
IS1 PROFIBUS 3.00 E
- Technical alterations reserved -
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PROFIBUS DP interface for IS1+
CPU redundancy according to PNO specification
In the PNO specification for PROFIBUS slave redundancy (Doc. 2.212 R1.2), different redundancy structures
have been defined. IS1 supports all versions of these redundancy structures. Master and Slave redundancy
are independent and can be combined optionally.
System Redundancy (SR):
Two seperate PROFIBUS Netzworks.
Primary- and backup slave
have the same address
Function:
During slave start-up, the DP master transmits specific parameters redundantly to the slaves and monitors the
connection both to the primary and the backup slave. Cyclic data are exchanged with the primary slave.
The decision to switch over when an error occurs is made by the slave. When a switchover takes place, the
previous backup CPU takes over and becomes primary. Input and output signals are frozen during the
switchover.
Optionally in case of system redundancy, the DP master can trigger a switchover of a redundant slave, for
example for testing, via a control command (DPV1 PrmCmd).
In case of flying redundancy the primary- and backup address of a redundant slave are exchanged during
switch over.
A failure of the backup CPU
is reported via the “Backup Slave Not Available” device-specific diagnosis as well
as the CPU status register in the cyclic data of the primary CPU.
Flying Redundancy (FR):
One logical PROFIBUS Netzwork.
Primary- and backup slave
have different addresses
