Expanded message frame configuration (SW 2.2 and
Description of Functions
With SW 2.2 and higher, the SINUMERIK 840Di system offers expanded message frame configura-
tion which allows you to cyclically transfer drive data in addition to process data from the drive (DP
slave) to the NC (DP master) by combining standard message frames and customized message
Select the required setting in the NC machine data:
Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
16.2 Expanded message frame configuration (SW 2.2 and higher)
The PROFIdrive profile provides two different possibilities for defining the quan-
tity and meaning of message frame data transferred between the DP master
and DP slave drives within the framework of the cyclic PROFIBUS communica-
1. Select a predefined standard message frame
You can uniquely define the quantity and meaning of the transferred data by
selecting a standard message frame type in the associated components DP
slave drive, DP master and NC.
2. Customizable message frame configuration
With customizable message frame configuration, a user-specific frame type
is defined, in which you need to separately inform each associated compo-
nent – DP slave, DP master and NC – of the quantity and meaning of the
The drive data transferred in addition to the standard message frame process
data must always be appended at the end of the standard message frame.
PDA for expanded message
Process data: Standard
. . . .
Fig. 16-1 Standard message frame with additional process data (PDA)
According to the selected functionality, for each axis the additional drive data is
available on the NC side in individual specified system variables or the entire
frame as an array of neutral data words via a general system variable. In both
cases, the system variables are read-only.
MD 36730: DRIVE_SIGNAL_TRACKING[n] (acquisition of additional drive
The specific drive data listed below is transferred in individually specified sys-
tem variables with the machine data setting:
MD 36730: DRIVE_SIGNAL_TRACKING[n] = 1
16 840Di Specific Data and Functions
. . . .