Siemens SINUMERIK 840D sl Function Manual page 1657

DB21, ...
DBB5 Rapid traverse override
Signal state 1 or The rapid traverse override can be entered via the PLC in either the binary or Gray code.
edge change For binary coding, the rapid traverse override is interpreted as a %.
0 → 1 0% to 100% feed changes are possible, in accordance with the binary value in the byte.
The following permanent assignment applies:
Binary values > 100 are limited to 100%.
Using the machine data:
MD12100 $MN_OVR_FACTOR_LIMIT_BIN (limit for binary-coded override switch),
the maximum rapid traverse override can be additionally limited.
In gray coding, the following codes are assigned to the individual switch settings:
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Z1: NC/PLC interface signals
19.12 Feeds (V1)
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