Siemens SINUMERIK 840C Installation Instructions Manual page 285

6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.6.1 General MD bits (general bits)
Bit 2 This bit indicates whether the programmed address extension or the M
and S address extension automatically generated by the control is to be
transferred to the PLC interface (in the control, the address extension is
always in force, except for emergency retraction).
This bit can be set if the control has more than one spindle. (The
extended M function must be decoded with DB80/DB30).
Bit 1 When using the Siemens tapping cycle L84 (G84) on the SINUMERIK
840M, it is necessary to indicate whether or not the spindle has an
encoder.
Bit 1 = 0 The spindle has an encoder (512 or 1024 pulses). G33 (pitch in
mm/rev) is therefore used in tapping cycle L84.
Bit 1 = 1 The spindle has no encoder or its encoder is not to be used for cycle
L84.
G63 (F in mm/min) is therefore used in tapping cycle L84. The
programmer must define feedrate and spindle speed so as to produce
the correct pitch. Slight errors are taken up by the compensating chuck.
Bit 0 At block boundaries in G63 (tapping without encoder), the programmer
can specify whether the new setpoint speed should be output with
consideration given to the acceleration characteristic or abruptly.
Bit 0 = 0 Acceleration characteristic
Bit 0 = 1 Abrupt setpoint speed
Note:
If the bit is set the exact stop limits are not taken into account on a block change. This means
that the existing path velocity is output to the axes of the next block. If a servo enable has not
been set for these axes, alarm 168* "Servo enable for traversing axis" is output.
To avoid this
• Program G09 (exact stop) in the last G63 block
• Approach the same drilling axis position with G0 or G01 in the next block
• Program a dwell time in the next block.
Bit 0 = 0
Speed
Bit 0 = 1
Speed
6–100
G63 with deceleration
G63 without deceleration
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Siemens AG 1992 All Rights Reserved
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SINUMERIK 840C (IA)