FCM 300 / FCD 300 / VLT
®
2800 / DP V1 PROFIBUS
System
layout
■ Profibus DP V1
The P rofibus DP extension DP V1 offers additional
to the cyclical data communication an acyclical
communication. This feature can be used by a
DP master type 1 ( e.g. PLC ), as well as a DP
master type 2 (e.g. PC tool).
Features of a Master type 1 connection
- Cyclical da ta exchange (DP V0).
- Acyclical read/write on parameters.
The acyclical conne ction is fixed, and can not
be changed during operation.
Features of a Master type 2 connection:
- Initiate / Abort ac yclical connection.
- Acyclical read/write on parameters.
The acyclical connection can dynamically be
established (Initiate) or removed (Abort) even when
a master class 1 is active on the network.
The DP V1 acyclical connection c an be used
for general parameter access as an alter native
to the PCV parameter channel.
■ Principle of data exchange by Profibus DP V0/DP V1
InaDPcycletheMC1willfirstupdatethecyclical
process d a ta for all slaves in the system. After that
the MC 1 has the possibility of sending one acyclical
message to one slave. If a MC 2 is connected,
the M C 1 will handle over the Token to MC 2 who
now is aloud to send one acyclical message to one
slave. Afte r that, the token is handled back to the
MC 1, and a new DP cycle is started.
MC1: Master Class 1
Closing the control loop over the bus Closing the control loop outside the fie ldbus
for extremely fast feed-back
MG.90.A5.02 - VLT is a registered Danfoss trademark
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