Siemens SPC3 - Manual (Page 60)

PROFIBUS Interface Center SPC3
Page 58 V1.3 SPC3 Hardware Description
2003/04 Copyright (C) Siemens AG 2003. All rights reserved.
9.2 Example for the RS 485 Interface
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Explanations of the circuitry:
The bus driver input EN2 has to be connected to low potential to ensure that after transmission of a
telegram the ASIC is able to listen to the transmitted data.
To minimize the capacity of the bus lines the user should avoid additional capacities. The typical capacity of
a bus station should be 15 ... 25 pF.