Siemens SINUMERIK 840D Function Manual page 56

G2: Velocities, setpoint / actual value systems, closed-loop control
2.4 Setpoint/actual-value system
Motor/load gear
The motor/load gear supported by SINUMERIK is configured via the following machine data:
● MD31060 $MA_DRIVE_AX_RATIO_NUMERA (numerator load gear)
● MD31050 $MA_DRIVE_AX_RATIO_DENOM (denominator load gear)
The transmission ratio is obtained from the numerator/denominator ratio of both machine data.
The associated parameter sets are used automatically as default by the control system to
synchronize the position controller with the relevant transmission ratios.
Since a gear stage change is not always carried out automatically, and there are also several
ways to request a gear stage change, the position controller is not always incorporated via
parameter sets.
Note
For further information about the parameter sets for gear stage change, see Section "S1:
Spindles (Page 733)".
Intermediate gear
Additional, configurable load intermediate gears are also supported by the control system:
● MD31066 $MA_DRIVE_AX_RATIO2_NUMERA (intermediate gear numerator)
● MD31064 $MA_DRIVE_AX_RATIO2_DENOM (intermediate gear denominator)
Power tools generally have their "own" intermediate gear. Such variable mechanics can be
configured by multiplying the active intermediate gear and the motor/load gear.
Different gear transmission ratios for switching
Unlike the motor/load gear, there is no parameter set for the intermediate gear and, therefore,
no way of controlling the time-synchronized switchover to the part program or PLC (NC/PLC
interface). Part machining during gear change is, therefore, ruled out. It remains the task of the
user to match the synchronization of the relevant changed machine data to the corresponding
mechanical switchover and activate it. On switchover during a motion, compensations cannot
be ruled out due to jumps in the scaling factors. These are not monitored for violation of the
maximum acceleration.
Encoder directly at the tool
Another connection option is possible for a "tool-side encoder" on the intermediate gear by
configuring the following machine data:
MD31044 $MA_ENC_IS_DIRECT2
Encoder not directly at the tool
The following supplementary conditions apply to a gear change of the intermediate gear in
position-control mode: The gear ratio to be changed is incorporated in a re-scaling of the
encoder information in this case.
56
CAUTION
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA