Siemens SINUMERIK 840D Function Manual page 673

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
comes to a standstill.
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: position reached <axis>"
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
Special features of modulo rotary axes
Modulo rotary axes can approach the fixed point in both directions. The shortest path (DC) is
not observed during the travel.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
H1: Manual traversing
17.9 Approaching a fixed point in JOG
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