Speed Monitoring, Encoder Limit Frequency - Siemens SINUMERIK 840D sl Function Manual

Safety functions integrated in the system/drive
7.5 Safely reduced speed (SG)
Functional features
The features of the SG function are as follows:
● Load-side speed limit values are safely monitored
● Monitoring limit values are adapted to various operating states (e.g. test, setting-up,
automatic modes)
● Configurable stop response when the SG responds
Preconditions
The following preconditions must be fulfilled:
● The option and functions must be enabled in the axis-specific machine data
● The SGEs "SBH/SG deselection" and "SBH deselection" must be configured
Specifying velocities and speeds
The requirements regarding speeds and velocities that are stipulated for individual processes
(milling, turning, grinding, etc.) vary depending on the different C Standards. For example, the
following could be specified for the setting-up mode:
Safely reduced velocity with 2 m/min for feed drives - or 50 rpm for spindle drives or standstill
within 2 revolutions.
The machine manufacturer must parameterize SI in such a way as to ensure full compliance
with the EC Machinery Directive. The relevant standards provide the necessary guidelines and
support.
Quantities that influence the parameterization include, e.g. the drive dynamic response, the
set parameters with their delay times, electrical and mechanical gear ratios and all of the
mechanical properties and characteristics. The interrelationships between the drive dynamic
response and internal delay times of SI are shown in the diagram "Timing when exceeding the
limit value for SG".
Note
Deviation of the speed limit
The safety-related actual speed limit can deviate slightly from the limit value set in MD36391[...]
for the safely reduced speed. The reason for this is the internal resolution of the speed values.
The safety-related actual speed limit is displayed in the diagnostics screen form Safety Safety
Integrated status.
7.5.1

Speed monitoring, encoder limit frequency

When SBH/SG is active in a configuration with a 1-encoder system, the speed is monitored to
ensure that it does not exceed a maximum encoder limit frequency. An appropriate alarm is
output if this limit is exceeded.
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Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated