Siemens SINUMERIK 840D sl Function Manual page 753

Setpoint changeover and Safety Integrated
In conjunction with the setpoint changeover, the SI functionality is only supported with a
restricted scope. At each setpoint changeover, the absolute position reference is lost. This
means that only SI functions can be sensibly and practically used that do not require absolute
position information. These functions include SBH, SH, SG, SBR, Stops and SPL.
Note
SE and SN are not supported.
The SI monitoring functions are only calculated in the axis configured for this - not taking into
account existing drive checking functions. This means that only this SI machine axis detects
SI fault/error states. The associated alarm responses are automatically effective for all of the
axes involved in the setpoint changeover.
MD36901 $MA_SAFE_FUNCTION_ENABLE may only be activated in the last machine axis
configured for the setpoint changeover. This fixed assignment is kept over all setpoint
changeover operations.
In conjunction with Safety Integrated, all of the axes, involved in the setpoint changeover, must
be configured in the same channel.
If the SI monitoring is also to be effective when traversing/moving non-SI axes, then it is not
permissible that the SI axis is parked during this time.
An axis with the drive checking function DB3x.DBX96.5=1 must be parked at the same time
as an SI axis. This means that the axis SI monitoring functions are de-activated synchronously
in the drive and in the SI axis. Parking the axis - must always be selected for both axes.
The "parking" operating state can only be exited using the axis with the drive checking function.
As a result of the mechanical changeover, the motor encoder (G1) – monitored using SI – is
moved from several axes one after the other. In order to be able to determine the correct speed
on the load side, the existing gearbox ratios of the axes involved must be sensibly emulated
(mapped) in the 8 elements of MD36921, MD36922 of the SI axis and the drive p9521, p9522.
In order that the correct gearbox ratio becomes effective in the SI monitoring function, the PLC
must select the associated SI gearbox ratio and change over the setpoint at the same time.
The SGEs to change over the gearbox stage must be safety-related and therefore be able to
be controlled through 2 channels. Channel 1 should evaluate the feedback signals from the
gearboxes, channel 2 should evaluate the feedback from the setpoint changeover
DB3x.DBX96.5 "Control of drive accepted". It is not permissible to use a 1-channel signal
source to control the SGEs.
2-encoder system
If the SI axis has two encoders, when changing over to the non-SI axes, it is not permissible
that the second safety encoder is de-coupled. Both SI encoders must be continuously in
operation. The gearbox ratio between the SI axis and the non-SI axes must be taken into
account when configuring the SI gearbox ratios.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Interaction with other functions
12.2 Setpoint switchover
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