Siemens SINUMERIK 840C User Manual
Page 730
10 Axis and Spindle Installation
01.99
10.4.4 Reference point approach
Remarks:
•
Only one axis per NC block can be programmed (e.g.
G74 C LF
)
•
From SW 5 up to 5 axes can be programmed in one NC block.
•
TRANSMIT or coupled motion must not be selected
•
G74 is non modal
•
Tool offset and zero offset, PRESET + DRF are suppressed internally with G74 and auto-
matically become active again after ”Reference point reached”. This also applies to G
functions such as e.g. G01, G90, G94 etc.
•
After the function "Program-controlled reference point approach with synchronization" has
been initiated, the "actual position" continues to be updated. The distance to go is
displayed as zero because no proper differential values are produced while this function is
active.
10.4.4.4
Referencing without programmed motion
(with SW 4 and higher)
Corresponding data
•
NC MD 240*
(Reference point value)
•
NC MD 244*
(Reference point offset)
•
NC MD 296*
(Absolute encoder offset)
•
NC MD 564* bit 0
(Reference point direction, negative)
•
Signal DB 32 DW K+2 bit 13
(Referencing without programmed motion)
•
Signal DB 32 DW K+2 bit 12
(Delay reference point approach)
General
With SW 4, referencing without programmed travel movement (without NC setpoint
assignment, referencing in follow up mode) is possible. This function is required for axes, for
example, that cannot be operated in position-controlled operation.
Function description
MD 560*, bit 6 ("Automatic reference point approach") is not evaluated, i.e. the user must
defined the approach direction himself with MD 564*, bit 0).
Reference point offset is then calculated for the selected direction. If reference point approach
is performed in different directions, different machine positions also result if the reference point
offset is not equal to zero.
Linear and rotary incremental encoders as well as distance-coded measuring systems can be
used. Absolute encoders (e.g. SIPOS encoders) can also be used.
The interface signal "Delay reference point approach" in DB 32 DW k + 1, bit 12 is evaluated
as for normal reference point approach.
10–40
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)