Siemens SINUMERIK 840Di Function Manual page 1546

Detailed Description
2.3 Configurable gear adaptation
Switchover
Switchover to a new transmission ratio is performed immediately by means of NewConfig.
From a technological viewpoint, the associated mechanical switchover process takes some
time, since, in mechanical terms, a different intermediate gear with rotating tool is being
installed.
Note
At zero speed, switchover is jerk-free. The user is therefore responsible for taking
appropriate precautions.
Applications in which switchover takes place during motion and which require smoothed or
soft speed transition can be handled using existing setpoint speed filters.
For more information about closed-loop control conditions, please refer to
References:
/FB1/ Descriptions of Functions, Basic Machine; Velocities, Setpoint/Actual-Value Systems,
Closed-Loop Control (G2)
2.3.3 If the gear step change is not acknowledged
Mode change
A gear step change that has not been acknowledged cannot be interrupted by a change in
operating mode (e.g., switchover to JOG).
The switchover is delayed by the maximum period entered in machine data:
MD10192 $MN_GEAR_CHANGE_WAIT_TIME.
If the gear step change is not acknowledged within this time, the NC will output an alarm:
Further events
Events that initiate reorganization will also wait until a gear step change is completed.
The time entered in machine data:
MD10192 $MN_GEAR_CHANGE_WAIT_TIME
determines how long the control waits before executing the gear step change.
If this time elapses without the gear step change being completed, the NC responds with an
alarm.
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Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Spindles (S1)