Siemens SINUMERIK 840D sl Function Manual page 187

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>"
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:
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
H1: Manual and handwheel travel
4.9 Approaching a fixed point in JOG
187