Siemens SINAMICS G120C Function Manual

3.7.6 Safe Speed Monitoring (SSM)
What is the effect of the SSM safety function?
The inverter with active SSM function monitors the motor speed. The inverter signals whether
the speed is above or below a limit value.
Table 3-9 An overview of the principle of operation of SSM
Safe Speed Monitoring (SSM) Standard inverter functions linked
with 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, then the inverter sig‐
nals "Speed below limit value" via a fail-safe digital output or
via PROFIsafe.
6SHHG
6SHHGEHORZWKH
OLPLWYDOXH
SSM
W
W

Figure 3-8 The principle of operation of SSM
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 is in conformance with IEC/EN 61800-5-2.
Application example
Example Possible solution
A centrifuge may only filled below a
certain minimum velocity.
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.
6SHHG
EHORZWKH
OLPLW
YDOXH
Description
3.7 An overview of the principle of operation of the safety functions
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
44 Function Manual, 01/2017, FW V4.7 SP6, A5E34261271B AD

Siemens SINAMICS G120C Specifications

General

Brand	Siemens
Model	SINAMICS G120C
Category	Inverter
Language	English