Siemens Sinumerik 840DiE sl - Expanded Message Frame Configuration;Evaluation of Internal Drive Variables

01/2007
18.2 Expanded message frame configuration/evaluation of internal drive variables
18-501
© Siemens AG 2007 All Rights Reserved
SINUMERIK 840Di sl Manual (HBIsl) -- 01/2007 Edition
18.2 Expanded message frame configuration/evaluation of
internal drive variables
18.2.1 Descriptio n of the fu n ctio n
To ensure that the internal drive variables are available for evaluation in the
NCK, these are transferred from the drive as additional process data (PDA) dur-
ing cyclic PROFIBUS communication and saved by the operating system in
system variables.
The additional PDA is appended at the end of the s tandard message frame.
PDA: Standard message frame
PDA1
..... PDAx+1PDAx PDAy.....
PDA: Additional
drive data
PDA for expanded message frame
Fig. 18-1 Standard message frame with additional process data (PDA)
According to the selected functionality, for each axis the additional PDA is avail-
able on the NCK 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:
S MD 36730: DRIVE_SIGNAL_TRACKING[n] (acquisition of additional drive
actual values)
To transfer drive variables to individual system variables you must set the fol-
lowing machine data:
S MD 36730: DRIVE_SIGNAL_TRACKING[n] = 1
The additional PDA must be configured in the message frame in the exact se-
quence specified in table 18-1.
Table 18-1 Specific drive variables
PZD
Drive variables System variables
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
The entire message frame with standard process data and additional process
data is transferred in a general system variable as an array of 16 --bit integer
data words via:
S MD 36730: DRIVE_SIGNAL_TRACKING[n] = 2
S System variable: $VA_DP_ACT_TEL[n, a]
where n = Index: 0.2,...15
a = machine axis identifier.
NC system
variables
Specific
system variables
General
system variable
1
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