Siemens SINUMERIK 840Di Function Manual page 1148

Detailed description
2.12 Block descriptions
• Feed override:
• Machine functions for INC and axis travel keys:
The handwheel selection signals of the MMC are decoded and activated in the associated
(machine) axis interface or geo axis interface of the relevant handwheel (only if FB 1
parameter "HWheelMMC := TRUE").
The associated LEDs of the machine control panel are derived from the acknowledgments
from the relevant selections.
Feedrate and spindle Start/Stop are not transferred to the interface, but output modally as a
"FeedHold" or "SpindleHold" signal. The user can link these signals to other signals leading
to a feed or spindle stop (this can be implemented, e.g., using the appropriate input signals
in FC 10: AL_MSG). The associated LEDs are activated at the same time.
The spindle direction (+, -) is not switched directly either, but made available as output
parameter "SpindleDir", permitting, for example, FC 18 to be parameterized. A spindle
enable signal is also switched via parameter "SpindleHold". One possible method of moving
a spindle directly is to preselect it as an axis so that it can be traversed via (axis) direction
keys.
If the machine control panel fails, the signals it outputs are preset to zero; this also applies to
"FeedHold" and "SpindleHold" output signals.
Multiple calls of FC 24 or FC 19, FC 25 are permitted within the PLC cycle from SW 4 and
higher. In this case, the first call in the cycle drives the LED displays. Moreover, all actions of
the parameterized block are performed in the first call. In the following calls, only a reduced
level of processing of the channel and mode group interface takes place.
The geometry axes are supplied with directional data only in the first block call in the cycle.
Single block processing can be selected/deselected only in the first call in the cycle.
The second machine control panel can be processed if parameter ModeGroupNo has been
increased by B#16#10. When parameterizing, the HHU number is contained in the lower
nibble (lower 4 bits).
BAGNo = 0 or B#16#10 means that the mode group signals are not processed.
ChanNo = 0 means that the channel signals are not processed.
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– The feed override is transferred to the interface of the selected channel and to the
interface of the axes.
– The feed override signals are transferred in addition to interface byte "Rapid traverse"
override (DBB 5) to the NC channel if MMC signal "Feed override for rapid traverse
effective" is set (exception: Switch setting "Zero"). "Rapid traverse override effective" is
also set with this MMC signal.
– When the MCS is selected, the signals are transferred to the interface of the selected
machine axis.
– When the WCS is selected, the signals are transferred to the geoaxis interface of the
parameterized channel.
– When the system is switched between MCS and WCS, the active axes are generally
deselected.
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0