Safe Speed Monitor Without Encoder - Siemens Sinamics S120 Function Manual

4.2.10.2

Safe Speed Monitor without encoder

Set p9506 = 1 or p9506 = 3 (factory setting = 0) to activate Safety Integrated functions
without encoder. You can also make this setting by selecting "Without encoder" on the
Safety screen in STARTER.
Without an encoder, the "Safe Speed Monitor" essentially functions exactly the same as
described in the previous section under "Safe Speed Monitor with encoder".
Not e
Def aults
For commissioning, also pay attention to the description in Chapter "Default settings for
commissioning Safety Integrated functions without encoder (Page 232)."
Not e
S et ting of t he OFF1 or OFF3 ramp-down t ime
If the OFF1 or OFF3 ramp-down time is too short or the difference between the SSM limit
speed and the shutdown speed is too small, the "speed below limit value" signal may not
change to 1, because no actual speed value could be determined below the SSM limit before
pulse suppression occurred. In this case, the OFF1 or OFF3 ramp-down time or the margin
between SSM speed limit and shutdown speed should be increased.
Differences between Safe Speed Monitor with and without encoder
● For Safe Speed Monitor without encoder, after pulse suppression the drive is unable to
determine the current speed. 2 responses can be selected for this operating state with
parameters p9509.0:
– p9509.0 = 1
– p9509.0 = 0
● Due to the less precise speed recognition, "Safe Speed Monitor without encoder" requires
a larger hysteresis (p9547) and, where applicable, a filter time (p9545) compared with the
function with encoder.
Safety Integrated
Function Manual, (FHS), 07/2016, 6SL3097-4AR00-0BP6
The status signal (SSM feedback signal) shows "0" (factory setting).
The status signal (SSM feedback signal) is frozen. "Safe Torque Off" (STO) is
selected internally.
Description of Safety Integrated functions
4.2 Safety Integrated Extended Functions
111