Siemens SIMOVERT MASTERDRIVES Manual page 391

Communication / PROFIBUS
Shift multiplier top
centre
Switch bottom
centre
Delay element
bottom right
Adder centre right
8.2-104
Implementation of DSC with free blocks
(see Fig. 8.2-36)
In MASTERDRIVES free calculating blocks are available, with the aid of
which the DSC function is implemented.
The individual elements of this implementation are described below:
The shift multiplier is used for conversion of the DSC gain DSC_GAIN
from an integer to a percentage value, which in turn is needed as input
for the KP adjustment position controller.
If the master application pulse (MAPC) is a multiple of the Profibus (DP)
pulse, the relevant position actual value, which enters the position
controller on the master side, must be stored internally. This is achieved
by scanning the actual position value synchronously with the life sign of
the Profibus master.
This dead time element delays the scanned actual position value. The
dead time must be selected according to the action time of a new actual
position value via the master position controller. With the combination of
SIMOTION as bus master and MASTERDRIVES as slave this dead time
in our experience is always 4 DP cycles, so the value 4 should be
entered in U401.
With the aid of this adder the current position setpoint is calculated from
the DSC position Xerr and the delayed actual position value.
6SE7087-6QX70 (Version AG)
Compendium Motion Control
05.2006
Siemens AG
SIMOVERT MASTERDRIVES