Siemens SINUMERIK 840D sl Function Manual page 333

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: <Axis> direction blocked"
Approaching other fixed point
The axis motion is cancelled and the following alarm is output if a different fixed point is
selected while traversing to the fixed point:
Alarm 17812 "Channel %1 Axis %2 fixed point approach in JOG: Fixed point changed"
The message signal DB31, ... DBX75.0-2 (JOG - Approaching fixed point active) displays the
number of the newly selected fixed point. The JOG traverse must be triggered again to
continue traversing.
Note
To avoid the alarm message, the machine user should proceed as follows:
1. Cancel the current traverse movement with residual distance deletion.
2. Activate fixed point approach for another fixed point and start the operation after the axis
Withdrawal from fixed point/deactivation
To withdraw from a fixed position, you must deactivate the "Approaching fixed point in JOG"
function. This is done by resetting the activation signal to "0".
DB31, ... DBX13.0-2 = 0
The message signals DB31, ... DBX75.0-2 (JOG - Approaching fixed point active) and
DB31, ... DBX75.3-5 (JOG - Approaching fixed point reached) are deleted on leaving the
fixed point position.
Special case: Axis is already on fixed point
The axis cannot be moved if, while starting the fixed point traverse, the axis is already at the
position of the fixed point to be approached. This is displayed through the following channel
status message:
"JOG: <Axis> position reached"
To withdraw from the fixed position, you must deactivate the "Approaching fixed point in
JOG" function.
Special features of incremental travel
If, during incremental travel, the fixed point is reached before the increment is completed,
then the increment is considered to have been completed fully. This is the case even when
only whole increments are traveled.
MD11346 $MN_HANDWH_TRUE_DISTANCE = 2 or 3
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
comes to a standstill.
H1: Manual travel and handwheel travel
4.10 Approaching a fixed point in JOG
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