How To Control The Fc 300; Ppo Types - Danfoss FC 300 Profibus Manual

FC 300 Profibus

How to Control the FC 300

PPO Types

The PROFIBUS profile for frequency converters specifies a number of communication objects (Parameter
Process data Objects, PPO), which are suitable for data exchange between a process controller, such as a
PLC, and frequency converters. All PPOs are defined for cyclic data transfer (i.e. DP V0), so that process data
(PCD) and parameters (PCA) can be transferred from the master to the slave and vice versa. The figure
below shows the PPO types available for the FC 300.
PPO types 3, 4, 6, 7 and 8 are pure process data objects for applications requiring no cyclic parameter
access. The PLC sends out process control data, and the FC 300 then responds with a PPO of the same
length, containing process status data. The first four bytes of the process data area (PCD 1 and PCD 2)
comprise a fixed part present in all PPO types. In the remaining bytes, from PCD 3 on, the process data can
be parameterised with process signals from the list in par. 9-23 Parameters for signal.
Select the signals for transmission from the master to the frequency converter in par. 9-15 PCD Write
configuration (request from master to FC 300). Select the signals for transmission from the frequency
converter to the master in par. 9-16 PCD Read configuration (response: FC 300 -> master).
PPO types 1, 2 and 5 consist of a parameter channel and process data. The parameter channel can be used
for reading and/or updating of parameters (successively). Alternatively, for better utilisation of I/O and thus
PLC capacity, parameters can be accessed via DP V1, in which case a pure process data object should
be chosen (PPO type 3, 4, 6, 7 or 8).
The choice of PPO type is made in the master configuration, and is then automatically recorded in the
frequency converter. No manual setting of PPO types in the FC 300 is required. The current PPO type can be
read in par. 9-22 Telegram selection.
In addition, all PPO types can be set up as word consistent or module consistent. For FC 300, the process
data area can be word or module consistent, whereas the parameter channel must always be module
consistent. Module consistent data is transmitted as sets of interrelated words transferred simultaneously
between the PLC program and the FC 300. Word consistent data is transmitted as individual independent
words between the PLC and the FC 300.
Selection [1] Standard telegram 1 is equivalent to PPO type 3.
25
MG.33.C2.02 - VLT is a registered Danfoss trademark