Feedrate Override Via Machine Control Panel - Siemens SINUMERIK 840D Function Manual

5.4.2

Feedrate override via machine control panel

Function
With the "Feedrate override via machine control panel", the operator can locally increase or
decrease the path feedrate at the machine as a percentage with immediate effect. To achieve
this, the programmed feedrates are multiplied with the override values available at the NC/PLC
interface.
The feedrate can be changed axis-specifically for positioning axes.
The "Spindle override" can be used to change the spindle speed and the cutting rate (G96,
G961).
With a feedrate change, the axial acceleration and velocity limits are maintained. There are no
contour errors along the path.
The feedrate override can be changed separately for path and position axes.
The overrides influence the programmed values or the limits (e.g. G26, LIMS for spindle speed).
Channel-specific feedrate and rapid traverse override
For feedrate and rapid traverse override, dedicated enable signals and correction/offset factors
are available in the NC/PLC interface:
DB21, ... DBX6.7 (feedrate override active)
DB21, ... DBB4 (feedrate override)
DB21, ... DBX6.6 (rapid traverse override active)
DB21, ... DBB5 (rapid traverse override)
The override factors can be specified from the PLC either in the binary or Gray-coded format.
The format is communicated to the NC via the following machine data:
MD12020 $MN_OVR_FEED_IS_GRAY_CODE (path feedrate override switch Gray-coded)
MD12040 $MN_OVR_RAPID_IS_GRAY_CODE (rapid traverse override switch Gray-coded)
The following permanent assignment applies to binary code:
With Gray coding, the override factors corresponding to the switch position must be entered in
the following machine data:
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
Binary code
00000000
00000001
00000010
00000011
00000100
...
01100100
...
11001000
Decimal
0
1
2
3
4
...
100
...
200
V1: Feedrates
5.4 Feedrate control
Override factor
0.00 ≙ 0%
0.01 ≙ 1%
0.02 ≙ 2%
0.03 ≙ 3%
0.04 ≙ 4%
...
1.00 ≙ 100%
...
2.00 ≙ 200%
159