ABB PFEA 113, User Manual

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Tension Electronics PFEA113, User Manual
Section 3.13 Profibus DP Communication with PFEA113
3BSE029382R0101 Rev C 3-39
3.13 Profibus DP Communication with PFEA113
3.13.1 General Data about Profibus DP
The purpose of the Profibus DP communication in PFEA113 is to provide a high speed
communication link between superior systems and the PFEA113.
Profibus DP is a multidrop communication protocol intended to connect PLCs to sensors (DP
means “Distributed Peripherals”).
The physical interface is RS 485 (two wire cable).
The maximum transfer rate is 12 Mbit/s.
The protocol is based on a master-slave principle. The PFEA113 is a slave. A Profibus master
polls the slaves all the time, that means the polling is going on with a fixed time interval even
when no new data is available from the PFEA113.
Each slave has an address in the range 0 to 125.
Profibus requires that the message format, communication parameters and error codes
of slaves are made available in a so called type file, also known as GSD file (See
Appendix A.8
Profibus DP - GSD File for PFEA113 ). This file is then stored in the Profibus Master.
At start-up the Profibus Master verifies that the Slave with the given type file is indeed available
on the bus.
3.13.2 Master-slave Communication
The Master and the slave communicate via an output buffer and an input buffer.
The master reads the input buffer and writes to the output buffer once every scan cycle for
Profibus.
The slave polls the output buffer and updates values in the input buffer.
Master - PLC
MC400
measuring
process
Output buffer
Input buffer
Slave – MC400
Master-PLC
Output buffer
Input buffer
Slave-PFEA113
PFEA113
measuring
process