6
Process data channel
The process data channel is used for real-time communication. This channel can effectively be
divided into two telegram portions:
PZD1:
Control word (STW) /Status word (ZSW) – instrument control
The control word and the status word are used to control the instrument and
monitor the status of the instrument.
PZD2-6:
Setpoint / actual values depending on the operating mode.
Setpoints and actual values such as position, velocity and current are exchanged
in this section.
The availability of a process data channel is determined in the PROFIDRIVE drive profile. The sig-
nificance of the process data is defined according to the operating mode. The process data that are
used are determined in such a way that the real-time capability of this channel is optimally used. A
central role is played by the parameter “Selector for operating modes” (see Chapter 5.2.2.3), that is
used to choose between individual operating modes.
In the following, the instrument control is described first, and then the significance and functioning of
the operating modes.
6.1
Instrument control
The control of the instrument is described with the aid of a status machine. The status machine is
defined in the drive profile by a flow diagram for all operating modes. The following diagram shows
the possible instrument states for the PMCtendo DD4.
User manual PROFIBUS DP PMCtendo DD4
Page 35
6 Process data channel
Output stage not
switched on
Error
Output stage
switched on
Start
Fast stop
Error
Eror response
active
Operation
enabled
Ready for
operation
Ready for
switch-on
Switch-on
inhibited
Not ready to
switch-on
