Safe Speed Monitor (Ssm) - Siemens SINAMICS G130 Manual

6.8

Safe Speed Monitor (SSM)

General description
Note
The "Safe Speed Monitor" function is only available for operation with an encoder.
The "Safe Speed Monitor" function is used for reliably detecting when a velocity limit value
has been undershot (p9346/p9546) (e.g. for standstill detection) in both directions. A fail-safe
output signal is available for further processing.
The function is activated automatically as soon as the Extended Functions are enabled with
p9301.0 = p9501.0 = 1.
NOTICE
If 0 is entered for p9368/p9568, the speed limit of the SSM function (p9346/p9546) is also
used as shutdown limit for the SBR function (safe braking ramp).
In this case, the effects of safe acceleration monitoring are therefore restricted if a relatively
high SSM/SBR velocity limit is set when using the SS1 and SS2 stop functions.
STOP F (indicated by safety message C01711/C30711) only results in a follow-up
response (STOP B / STOP A) if one of the safety functions (SOS or SLS) is active or has
been selected. If only the SSM function is active, a STOP F crosswise comparison error
does not result in a follow-up response STOP B / STOP A.
If SSM is to be used as a safety function, at least one of the SOS or SLS functions must be
active/selected (e.g. by selecting a high SLS level).
Functional features of "Safe Speed Monitor with encoder"
The parameter p9346/p9546 "SI Motion SSM (SGA n < nx) velocity limit n_x (CU)" is used to
set the velocity limit. The abbreviation "SGA n < nx" indicates the safety function required for
determining an output signal when a parameterizable velocity limit has been undershot.
If the velocity limit for the "Safe Speed Monitor" feedback signal (n < n_x) is undershot, the
"SSM feedback signal active" signal (SGA n < n_x) is set. When the set threshold value has
been undershot, the "Safe Acceleration Monitor" (SBR) function is also deactivated (see
p9368/p9568). If p9368 = p9568 = 0, then p9346/p9546 (SSM feedback signal) is also used
as a trip threshold for the SBR monitoring.
Safety Integrated
Function Manual, 05/2010, A5E03264275A
WARNING
Safety Integrated Extended Functions
6.8 Safe Speed Monitor (SSM)
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