Expanded Message Frame Configuration/Evaluation Of Internal Drive Variables; Description Of Functions - Siemens SINUMERIK 840Di sl Commissioning Manual

18.2 Expanded message frame configuration/evaluation of internal drive
variables
18.2.1

Description of functions

To ensure that the internal drive variables are available for evaluation in the NC, these are
transferred from the drive as additional process data (PDA) during cyclic PROFIBUS
communication and saved by the operating system in system variables.
The additional PDA is appended at the end of the standard message frame.
Figure 18-1
NC system variable
According to the selected functionality, for each axis the additional PDA 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.
Select the required setting in the NC machine data:
● MD36730 $MA_DRIVE_SIGNAL_TRACKING[n] (acquisition of additional drive actual
Specific system variables
To transfer drive variables to individual system variables you must set the following machine
data:
● MD36730 $MA_DRIVE_SIGNAL_TRACKING[n] = 1
The additional PDA must be configured in the message frame in the exact sequence
specified in the following table.
Table 18-1
PZD
x+1
x+2
x+3
x+4
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0

18.2 Expanded message frame configuration/evaluation of internal drive variables

Standard message frame with additional process data (PDA)
values)
Specific drive variables
Drive variables
Load
Smoothed torque setpoint (Mset)
Active power (Pact)
Smoothed torque-producing current Iq (IqGl)
840Di-specific data and functions
System variable
$AA_LOAD
$AA_TORQUE
$AA_POWER
$AA_CURR
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