Safe Speed Monitoring (Ssm) - Siemens SINAMICS G120 Function Manual

3.12

Safe Speed Monitoring (SSM)

How does SSM function?
Table 3- 9 The principle of operation of SSM
Safe Speed Monitoring (SSM)
1. The SSM function cannot be
selected or deselected using
external control signals, in the
appropriate setting, it is always
active.
2. The inverter compares the motor
speed with an adjustable limit
value.
3. If the speed is less than the limit
value, the inverter signals "Speed
below limit value" via a safety
output or via safety-related
PROFIsafe communication.
The SSM safety function is standardized
The SSM function is defined in IEC/EN 61800-5-2:
"The SSM function supplies a safe output signal to indicate whether the motor speed is
below a specified limit value."
The SSM inverter function complies with what is defined in the standard.
Application example
Example
A centrifuge may only filled below a certain
minimum velocity.
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
Function Manual, 04/2014, FW V4.7, A5E34261271B AA
3.12 Safe Speed Monitoring (SSM)
The inverter with active SSM function signals
whether the velocity or speed of a machine
component is above or below a limit value.
Possible solution
The inverter safely monitors the centrifuge
speed and enables the process to advance to
the next step using the status bit "Speed below
limit value" via PROFIbus.
Description
Standard inverter
functions linked with SSM
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