Siemens SINUMERIK 840D Function Manual page 672

H1: Manual traversing
17.9 Approaching a fixed point in JOG
Activation
After selecting the "Approach fixed point in JOG" function, the PLC outputs the number of the
fixed point to be approached binary coded to the NC using the following bits:
DB31, ... DBX13.0 - 2 (JOG approach fixed point)
The NC confirms the activation with the interface signal as soon as the function is effective:
DB31, ... DBX75.0 - 2 (JOG approach fixed point active)
Note
Activation is not possible:
● during an NC reset
● In case of impending emergency stop
● During processing of an ASUP
No alarm message occurs. Delayed activation takes place after closure or after
acknowledgement of the active function.
Sequence
The actual traversing is started with the traverse keys or the handwheel in the direction of the
approaching fixed point.
The selected machine axis traverses till it comes to an automatic standstill at the fixed point.
The corresponding NC/PLC interface signal is reported on reaching the fixed point with "Exact
stop fine":
DB31, ... DBX75.3 - 5 (JOG approach fixed point reached)
This display signal is also signaled if the axis reaches the fixed point position in the machine
coordinates system via other methods e.g. NC program, FC18 (for 840D sl) or synchronized
action on the setpoint side and comes to a standstill on the actual value side within the "Exact
stop fine" tolerance window (MD36010 $MA_STOP_LIMIT_FINE).
Movement in the opposite direction
The response while traversing in the opposite direction, i.e. against the direction of the
approaching fixed point, depends on the setting of Bit 2 in the machine data:
MD10735 $MN_JOG_MODE_MASK (settings for the JOG mode)
Traverse in the opposite direction is possible only if the bit is set.
Traverse in the opposite direction is blocked if the bit is not set and the following channel status
message is output if an attempt is made with the traverse keys or with the handwheel to
traverse in the direction opposite the approaching fixed point:
"JOG: Direction blocked <axis>"
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Axes and spindles
Function Manual, 06/2019, A5E47437747B AA