Siemens SINUMERIK 840C Installation Instructions Manual page 1082

09.95 12 Functional Descriptions
12.30.3 Function description
Parameterization with the NC machine data
The slave is parameterized via the NC machine data. This is only a short list with a few notes
relevant to the function:
Basic package
MD axis/MD spindle
MD 1336*/2700*
MD 1812*, bit 4/*523* bit 4:
MD 1812*, bit 7/*523* bit 7:
Additional MDs for torque compensation control
MD axis/MD spindle
MD 1340*/2701*
MD 1344*/2702*
MD 1384*/2703*
MD 1288*/2704*
MD 1812*, bit 5/*523* bit 5:
MD 1812*, bit 6/*523* bit 6:
With MD 1344*/2702*, the input quantities of the torque compensation control are weighted to
permit a parameterizable torque distribution over both drives.
The most uniform torque distribution even during acceleration is obtained if the torque
compensation controller does not have to intervene in the command behaviour. If identical
motors are used with identical drive parameterization and they all have to output the identical
torque, the standard parameterization of 500‰ is the best setting. This is also recommended
where master/slave operation gives the best results.
If the motors are different, the user can decide whether both motors are to output the same
torque or whether the torques are to be distributed according to the moments of inertia or
rated torques. Distribution according to the moments of inertia of the motors is recommended
with the aim of achieving the same ramp-up time for both drives.
The standard parameterization of 500‰ results in a distribution according to values in drive
machine data 1725 (normalization of the torque setpoint interface) for both axes. For another
distribution, the MD 1344*/2702* must be calculated according to the following formula:
M
desired
slave
NC MD 1344*/2702* = ––––––––––––––––––––––––––––––––––––––––– · 1000‰
MD1725
slave
M +M * –––––––––––––
desired desired
MD1725
slave master
master
M is the ideal torque distribution between master and slave.
desired
The torque compensation control can be connected as required via MD 1340*/2701* and
1812*/523*. If MD 1336* and 1340* are set differently it is possible to implement a chained
multi-slave structure. However, it is up to the user to make sensible parameterization. In the
system software a check is only made that the drive in question can provide its torque setpoint
(SIMODRIVE 611D).
The control output parameterized in bits 5 and 6 of the axial MD 1812* acts either on the
master or the slave. With the default setting 0 in these bits, the switches in the diagram are
open.
With bit 7 in MD 1812*/523*, it is possible to take account of different ways of connecting the
slave drive to the common output without having to change the polarity of the control and the
direction of travel of each axis. All the relevant signs of the slave are inverted.
12–307
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SINUMERIK 840C (IA)