SIEB & MEYER SD2, Translation Of The Original Instructions

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6 Fieldbus Communication
The safety PLC communicates via several layers with the drives. The PLC program
sends the reference data via fieldbus interface to each SD2 drive amplifier. The actual
values are transmitted in reverse direction.
The SD2 software detects the following errors:
▶ bit error
▶ timeout
▶ telegram failure
▶ addressing (COB-ID)
▶ test pattern
Fig. 10: Fieldbus communication
The communication between PLC program and SD2 software takes place on the
layers 7 and 8. of the ISO communication model. Therefore, the in-between transmis‐
sion layers are not relevant for the safety of the communication path.
To prevent configuration errors of the bus system the data to be transmitted contain
the COB-ID (communication object identifier). Thus, the software can check the COB-
ID and detect any configuration errors immediately.
For detailed information on fieldbus communication contact SIEB & MEYER.
The safety functions SFM and SLOF are monitored in the SD2 module by
two safety controllers (SC0 and SC1). Together the safety controllers
monitor both safety functions (SFM and SLOF) for both drives (A and B) of
the module. For full data transmission and evaluation the PLC must always
address both safety controllers (SC0 and SC1).
6.1 Data Transmission
The data are transmitted via the acyclic service data channel of the respective bus
protocol.
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Fieldbus Communication
Drive System SD2 - Safety Functions SFM / SLOF 25
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