Siemens SINUMERIK 840D sl Function Manual page 346

Detailed Description
2.1 General functionality
If no torque has been programmed in the block or since the start of the program, then the
value is valid in the axis-specific machine data:
MD37010 $MA_FIXED_STOP_TORQUE_DEF
(Default setting for clamping torque)
is entered.
Fixed stop reached
As soon as the axis comes into contact with the mechanical fixed stop (workpiece), the
closedloop control in the drive raises the torque so that the axis can move on. The torque
rises up to the programmed limit value and then remains constant.
The "Fixed point reached" status can be calculated as follows depending on the machine
data:
MD37040 $MA_FIXED_STOP_BY_SENSOR (fixed stop recognition by sensor)
:
• FIXED_STOP_BY_SENSOR = 0
• FIXED_STOP_BY_SENSOR = 1
• FIXED_STOP_BY_SENSOR = 2
The axis contour deviation is explained in:
References:
/FB1/ Function Manual Basic Function; Diagnostics tool (D1)
Internal processes
Once the NC has detected the "Fixed stop reached" status, it deletes the distancetogo and
the position setpoint is made to follow. The controller enabling command remains active.
Subsequently the PLC is through the NST DB31, ... DBX62.5 ("Fixed stop reached")
informed.
If the machine data:
MD37060 $MA_FIXED_STOP_ACKN_MASK
is set correspondingly, the acknowledgement of the PLC via the NST DB31 is, ... DBX1.1
("Acknowledge fixed stop reached") is waited for.
10
The "Fixed stop reached" status is achieved when the axial contour deviation (=
difference between actual and expected following error) has exceeded the value set in
machine data:
MD37030 $MA_FIXED_STOP_THRESHOLD (Threshold for fixed stop detection)
has exceeded.
External sensor signals the NC via the PLC, with the NST DB31, ... DBX1.2 ("Sensor
fixed stop"), the state "Fixed stop reached".
The "Fixed stop reached" status is active either when the status has been detected by the
contour monitoring function or when the external sensor signals this status by a signal
change from 0 " 1 to (DB31,...DBX 1.2).
Basic logic functions: Travel to fixed stop (F1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0