ABB FSPS-21 User Manual

Drive STO state
& indication
2
STO request
Motor speed
Time
1
DescriptionStep
The STO request is received from the safety PLC. The module activates the drive STO function.
The STO indications in the drive and safety PLC go on.
1
The STO request is removed from the safety PLC. The STO function is deactivated and the indica-
tions go off.
2
￭ SS1 with time monitoring
The SS1-t function stops the motor safely by ramping down the motor speed. The FSPS-21
module activates the drive STO function when zero speed limit, defined with parameter
21.06 Zero speed limit, is reached.
The SS1 function uses drive parameter 23.23 Emergency stop ramp to define the stop
ramp, see section Drive parameters related to safety functions (page 43) for more information.
The FSPS-21 module monitors the stop ramp with a time limit. If the motor speed does not
reach the user-defined zero speed limit within the specified time limit, the module activates
the drive STO function, the motor coasts to a stop, and FSPS-21 creates a fault (0x7aa0).
The SS1 time limit 0.0...3276.7 s is set by the safety PLC in PS3 telegram SS1-t_time
variable, see section ABB_PS3 profile F-Output user data (page 116).
The operation of the SS1 with time monitoring (SS1-t) is described in the time diagram and
table below.
28 Safety functions

ABB FSPS-21 Specifications

General

Brand	ABB
Model	FSPS-21
Category	Control Unit
Language	English