Siemens Simovert Masterdrives Compendium page 418

Communication / PROFIBUS
8.2.9 MASTERDRIVES as PROFIdrive V3-Slave
Requirements
New functions of the
PROFIdrive-Profile
Version 3
8.2-88
CBP2 with clock synchronization is not supported by MASTERDRIVES
VC.
Variable speed electric drives in automated units, from the simple
frequency converter to the highly dynamic servo controller, are now
increasingly being connected to higher-level open-loop and closed-loop
control systems via digital interfaces.
In current systems the standard speed interface is one in which the
speed command is given by the higher-level automation system and is
tracked by the drive. For monitoring, the actual speed value is generally
reported back to the automation system.
So that the digital field bus interface can also be used for motion control
with multiple axes in decentralised automation concepts, the current
standard field buses must be supplemented by specific properties.
The following requirements must be met:
Clock synchronization
In the case of a central motion controller, which performs interpolation
and position control, the control circuit must be connected via the bus. In
the setpoint direction the speed setpoint is transmitted to the drive. In the
actual value direction the drive returns the actual position value. In order
to be able to achieve sufficiently high circuit gain for the dynamic
required, the dead times must be small and above all absolutely
constant. If the motion control task requires coordination of several axes,
the position actual value must be recorded exactly simultaneously and
evaluated synchronously in the motion controller, and the setpoints must
take effect exactly simultaneously in the axes. Actual value recording,
transmission and setpoint setting are therefore clock synchronous with
the position controller.
This document contains the relevant extracts from the Profi-Drive-Profil
document (PROFIBUS Nutzerorganisation e. V., Order no.: 3.171,
http://www.profibus.com), in which the use of clock synchronous
transmission, of cross traffic and a position encoder interface and the
standardisation and configuration of the setpoints and actual values for
the drives are manufacturer-neutral and openly standardised.
6SE7087-6QX70 (Version AK)
Compendium Motion Control
09.2008
Siemens AG
SIMOVERT MASTERDRIVES