Safe Speed Monitor (Ssm) - Siemens Sinamics S120 Function Manual

Description of Safety Integrated functions
4.2 Safety Integrated Extended Functions
4.2.10

Safe Speed Monitor (SSM)

The "Safe Speed Monitor" (SSM) function provides a reliable method for detecting when a
speed limit has been fallen below (p9546) in both directions of rotation, e.g. for zero speed
detection. A fail-safe output signal is available for further processing.
The function is activated automatically as soon as the Safety Integrated Extended Functions
are enabled with parameter p9501.0 = 1 and p9546 > 0. The SSM function is deactivated
with setting p9546 = 0.
Not e
Relationship between SSM and S AM
If 0 is entered for p9568 (SAM shutdown threshold), the speed limit of the SSM function
(p9546) is simultaneously the lower limit for the Safe Acceleration Monitor function (SAM).
In this case, the effects of safe acceleration monitoring are therefore restricted if a relatively
high SSM velocity limit is set when using the SS1 and SS2 stop functions.
Not e
Danger due to unwanted behavior of the S TOP F on SSM
A STOP F is indicated by safety message C01711. STOP F only results in the follow-up
response STOP B / STOP A if one of the Safety functions is active. If only the SSM function
is active, a STOP F cross-checking error does not result in a STOP B / STOP A follow-up
response.
• SSM is only valid as an active monitoring function if "Hysteresis and filtering" is
parameterized (p9501.16 = 1).
Not e
P arameterization of hysteresis and actual value synchronization
You must carefully observe the following rules when parameterizing hysteresis and actual
value synchronization:
• If "SSM hysteresis" has been enabled (p9501.16 = 1), you must set parameters p9546
and p9547 according to this rule:
p9547 ≤ 0.75 × p9546
• If "Actual value synchronization" has been enabled (p9501.3 = 1), you must also observe
this rule:
p9549 ≤ p9547
Features
● Safe monitoring of the speed limit specified in p9546
● Parameterizable hysteresis via p9547
● Variable PT1 filter via p9545
● Safe output signal
● No stop response
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Function Manual, (FHS), 07/2016, 6SL3097-4AR00-0BP6
Safety Integrated