Siemens SINUMERIK 808D Function Manual page 67

Movement in the opposite direction
The response while traversing in the opposite direction (i.e. in the opposite direction to the one used when approaching the
fixed point) depends on the setting of bit 2 in the following machine data:
MD10735 JOG_MODE_MASK (settings for "JOG" mode)
Traversing in the opposite direction is only possible if bit 2 is set.
Traversing in the opposite direction is blocked if bit 2 is not set, and the following channel status message is output if an
attempt is made (using the traversing keys or the handwheel) to traverse in the opposite direction to the one used when
approaching the fixed point:
"JOG: <Axis> direction blocked"
Approaching other fixed point
If a different fixed point is set during the fixed-point approach, the axis motion is stopped and the following alarm is signaled:
Alarm 17812 "Channel %1 axis %2 fixed-point approach in JOG: Fixed point changed"
The message signal "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".
DB380x.DBX1001.0-2 = 0
The message signals "JOG - Approaching fixed point active" and "JOG - Approaching fixed point reached" are canceled 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 HANDWH_TRUE_DISTANCE = 2 or 3
Features of modulo rotary axes
Modulo rotary axes can approach the fixed point in both directions (bit 2 of MD10735 has no significance for them). No
attempt is made to follow the shortest path ( ) during the approach.
DC
Features of spindles
A spindle changes to the positioning mode on actuating the "Approaching fixed point in JOG" function. The closed loop
position control is active and the axis can traverse to the fixed point.
If a zero mark has not been detected, the following alarm message is output (as with axis operation):
Alarm 17810 "Channel %1 axis %2 not referenced"
As a spindle must also be a modulo rotary axis at all times, the same conditions apply for direction observation as for
modulo rotary axes (refer to the paragraph "Features of modulo rotary axes")
Function Manual
67
01/2017