Gearbox With Direction Of Rotation Reversal - Siemens SINUMERIK 840D sl Function Manual

● As a result of the gearbox stage changeover, the encoder evaluation for the safety-related
actual values change. Ideally, the gearbox stage for Safety Integrated is changed-over at
standstill. However, this is generally not in-line with what is required in practice. This means
that the actual value offset when changing-over the gearbox stage (e.g. using oscillation)
may not be greater than the already mentioned actual value tolerance window (MD36942 /
p9542).
● If, for the axis with selector gearbox, position-dependent monitoring functions are activated
- such as SE or SN - the user agreement (assuming that it was previously set) is withdrawn
when changing-over the gearbox ratio and the SGA "axis safely referenced" is set to 0.
When the gearbox stage is changed from the PLC and/or by selecting a new ratio, a new
gearbox ratio is detected using the appropriate SGEs.
● After the gearbox stage has been selected, the spindle must be resynchronized. When
resynchronizing the spindle, the two safety-related actual values (NCK and drive) are
reinitialized with the newly synchronized actual value. A possible difference that was
previously present between the two safety-related actual values is therefore corrected.
● In order to be able to re-use the SN or SE function after the gearbox ratio has been selected
(changed), the user must bring the spindle into the state "axis safely referenced" - the user
agreement must be re-issued.
● For 2-encoder systems, the gearbox ratio does not have to be selected in a safety-related
fashion and can be implemented through one channel. On the other hand, for a 1-encoder
system, the ratio selection must implemented using safety-related technology - i.e. using
two channels.
Decoupling
When a new stage is selected for a selector gearbox (the ratio changed), an axis is parked
or the mounting situation is modified (encoder and motor replaced), then this means that the
load and encoder have been decoupled. The NC and drive cannot detect this. The state "axis
safety referenced" is no longer applicable.
The user is responsible in bringing the axis back into the "axis safely referenced" state if the
functions "safe software limit switch" or "Safe Cams" are used.
6.4.5.2

Gearbox with direction of rotation reversal

Support for mechanical gearboxes with gearbox stage-specific direction of rotation reversal
To ensure that the speed and position actual values on the load side are evaluated correctly
by the safe monitoring functions, gearbox stages with direction of rotation reversal are taken
into account. To realize this, all gearbox stages - both on the NC side as well as on the drive
side (p9539) - can be parameterized with direction of rotation reversal.
The direction of rotation reversal of the individual gearbox stages is taken into account for axes
and spindles, as well as for 1-encoder and for 2-encoder systems.
To take into account the direction of rotation reversal, analogous to drive parameter p9539 "SI
Motion gearbox direction of rotation reversal", axis-specific safety machine data
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Basics regarding the safety functions integrated in the system/drive
WARNING
6.4 Actual value conditioning
95