840Di-specific data and functions
18.2 Expanded message frame configuration/evaluation of internal drive variables
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
589
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.
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Figure 18-1 Standard message frame with additional process data (PDA)
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
values)
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 Specific drive variables
PZD
Drive variables
System variable
x+1
Load
$AA_LOAD
x+2
Smoothed torque setpoint (Mset)
$AA_TORQUE
x+3
Active power (Pact)
$AA_POWER
x+4
Smoothed torque-producing current Iq (IqGl) $AA_CURR
