Interaction With Other Functions; Limiting The Speed Setpoint - Siemens SINUMERIK 840D sl Function Manual

Interaction with other functions

12.1

Limiting the speed setpoint

The setpoint speed is parameterized as a function of the active safety monitoring in MD36933
$MA_SAFE_DES_VELO_LIMIT. This machine data is not incorporated in the axis-specific
checksum MD36998 $MA_SAFE_ACT_CHECKSUM, so that changes can be made to the MD
for the acceptance test without having to again change the checksum.
If the spindle speed is limited by the SG-specific setpoint limiting, then this is displayed using
the axis-specific status signal DB3x.DBX83.1.
MD = 0%:
setpoint limiting inactive
MD > 0%:
setpoint limiting = active SG limit multiplied by MD value
For SBH setpoint limit = 0
MD = 100%:
setpoint limiting = active SG limit
For SBH, setpoint limit = 0
● The function is effective in one channel in the NCK interpolator. The safety monitoring
channel provides a limit value that corresponds to the selected safety monitoring type.
● This function influences both axes and spindles.
● The active setpoint limit can be viewed in the safety service screen:
Display value = -1. corresponds to "setpoint limiting not active"
Display value >= 0. corresponds to "setpoint limiting active"
● The setpoint limit is changed-over when the SGE is changed-over:
SGE "SBH/SG deselection"
SGE "SBH deselection"
SGE "active SG stage, bits 0, 1"
SGE "SG override, bits 0, 1, 2, 3"
– Further, internal changeover operations in SBH have an effect as a result of a stop
– Using axis-specific signals DB3x.DBX34.0 ... 1, the user can select a value from the MD
● For the changeover via SGE, the states from both monitoring channels are taken into
consideration to take into account differences in the times. This results in the following rules:
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
response (STOP D, C, E)
field 36933 $MA_SAFE_DES_VELO_LIMIT[0..3]. This means that independent of the
active SG stage, one of four parameterized setpoint speed limits can be activated. If the
PLC user program does not provide an input value, then the value in MD
$MA_SAFE_DES_VELO_LIMIT[0] applies
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