Siemens SINUMERIK 840D sl Function Manual page 1570

Z1: NC/PLC interface signals
19.1 Various interface signals and functions (A2)
DB31, ...
DBX1.4
Follow-up mode
Signal state 0 Follow-up mode is not active:
● The position setpoint is not tracked: Position setpoint = programmed set position
● Feedback signal: DB31, ... DBX61.3 = 0 (follow-up not active)
● Standstill and clamping monitoring are active.
Note
If the controller enable is reset (DB31, ... DBX2.1 == 0), the axis is in the "hold" state. Whereby the
set position of the axis is not corrected to the actual position. If the axis is moved in this state, e.g.
manually, the difference between the set position and the actual position increases constantly (fol‐
lowing error). The following error is suddenly corrected to zero when the "Controller enable" is set
(speed setpoint jump).
Special cases, If the controller enable is cancelled in the control because of faults, the "hold" state should be activated
errors, .... for the axis before the NC start after the queued alarms have been successfully deleted, and the
accompanying controller enable set: DB31, ... DBX1.4 = 0 (follow-up mode).
Otherwise, for an NC Start and active follow-up mode, the traversing distance of the previous NC
block would not be executed due to the internal delete distance-to-go.
Notice:
During the transition from the "follow-up" state to the "hold" state or when the controller enable is set
in position control, delete distance-to-go is activated in the control. As a consequence, a traversing
block in which only this axis is traversed, is terminated directly.
Corresponding to ... DB31, ... DBX2.1 (controller enable)
DB31, ... DBX2.3 (clamping in progress)
DB31, ... DBX61.3 (follow-up active)
DB31, ...
DBX1.5 - DBX1.6
Position measuring system 1 (PMS1) / Position measuring system 2 (PMS2)
Edge evaluation: No
Signal state 1 The position measuring system is active
Signal state 0 The position measuring system is inactive
1570
Signal(s) updated: Cyclically
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions