Operating instructions

1.6. Technical Overview
1.6.1. Bus Topology
Single master
- PLC communicates with telegrams of
constant length
- Fits time-critical requirements
- Cyclical transmission via PPO types
- Extended diagnosis
Illustration 1.1: PROFIBUS DP V0
1.6.2. Bus Topology
Multiple master
Features of a Master class 1 connection
- Cyclical data exchange (DP V0)
- Acyclical read/write on parameters
- Extended diagnosis
The acyclical connection is fixed, and cannot
be changed during operation.
Features of a Master class 2 connection:
- Initiate / Abort acyclical connection
- Acyclical read/write on parameters
The acyclical connection can be established
(Initiate) or removed (Abort) dynamically
even when a master class 1 is active on the
network. The DP V1 acyclical connection can
be used for general parameter access as an
alternative to the PCV parameter channel.
Illustration 1.2: PROFIBUS DP V1
The PROFIBUS DP extension DP V1 permits acyclical as well as cyclical data communication. This
feature can be used by a DP master class 1 (e.g. PLC), as well as a DP master class 2 (e.g. PC
tool).
1. Introduction VLT
®
Profibus
8 MG.33.C4.02 - VLT
®
is a registered Danfoss trademark
1