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Parameters to the Control and the PLC Pro
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6.8 Scaling machine data
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Siemens AG 2000 All Rights Reserved
SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
6.8 Scaling machine data
Machine data also include data which define how machine data are scaled with
respect to their physical unit (e.g. velocities).
The following machine data refer to scaling:
S MD 10220: SCALING_USER_DEF_MASK (activation of scaling factors)
S MD 10230: SCALING_FACTORS_USER_DEF (scaling factors of physical
quantities)
S MD 10240: SCALING_SYSTEM_IS_METRIC (basic system metric)
S MD 10250: SCALING_VALUE_INCH (conversion factor for switchover to
INCH system)
S MD 30300: IS_ROT_AX (rotary axis)
When machine data are loaded (via MMC, V.24 interface, program), they are
scaled according to the physical unit which is currently valid. If this data record
contains a new scale (e.g. rotary axis declaration), those machine data which
are dependent upon scaling data are converted to the new scale after the next
“POWER ON”. The MDs do not then contain the expected values (e.g. rotary
axis traverses at very low F values).
Example:
The control has been started up with default values. The 4th axis is defined as a
rotary axis in the MD file to be loaded and contains the following machine data:
axis is defined as a rotary axis and contains the following machine data:
$MA_IS_ROT_AX[A1] = 1 (rotary axis)
$MA_MAX_AX_VELO [A1] = 1000 [rev/min] (maximum axis velocity)
When the MD block is loaded the velocity is interpreted with respect to a linear
axis (default setting $MA_IS_ROT_AX[A1]=0) and normalized according to the
linear velocity.
During the next POWER ON process, the control detects that this axis is de-
fined as a rotary axis and normalizes the velocity with reference to rev/min. The
value in the machine data is then no longer “1000”, but “2.77777778”
(1000/360).
If the MD file is loaded again, the axis is already defined as a rotary axis and the
velocity is interpreted as the rotary axis velocity. The MD then contains the
value “1000” that is interpreted in rev/min by the control system.
Either
S Change the relevant machine data by hand via the MMC (MD 10220,
10230, 10240, 10250, 30300) followed by NCK power-up. After that, read in
the MD set via V.24 and start an NCK power-up, or
S Create an MD set with the standard machine data (MD 10220, 10230,
10240, 10250, 30300). Load this MD set and initiate an NCK power-up. After
that read in the complete MD set and start an NCK power-up, or
Scaling
machine data
Step-by-step
loading of
machine data
12.97
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