ABB FSO-21 - Page 114

114 Safety functions
With an encoder
A Zero speed with encoder (parameter FSOGEN.52): Speed limit at which the motor has
stopped, the safety function is completed and the SSE completed indication (parameter
SSE.22) goes on. The acknowledgment becomes allowed.
B SBC delay (parameter SBC.12): Time from the activation of the drive STO function to the
moment when the FSO activates the SBC function (brake).
In this case, the value is
negative and the FSO activates the SBC before the drive STO. If the value is zero, the
FSO activates the SBC and drive STO functions at the same time.
C Response time (depends on system configuration, see page 532)
Step Description
1 The SSE request is received (for example, from the I/O). The FSO activates the SBC
and starts a counter for time B. SSE active indication SSE output (SSE.21) and STO
output (STO.21) go on.
2 After time C has elapsed, the SBC starts to brake the motor.
3 After time B has elapsed, the FSO activates the drive STO function.
4 The motor speed reaches the zero speed limit (A), the FSO module defines the motor
as stopped and the SSE completed indication goes on. The acknowledgement
becomes allowed as soon as the SSE request has been removed (step 5).
5 The SSE request is removed.
6 After the acknowledgement, the SSE, STO and SBC functions are deactivated, and
the control is given back to the drive, which controls the brake from now on. The
indications SSE output (SSE.21), SSE completed output (SSE.22), and STO output
(STO.21) go off.
Drive STO state
& indication
SSE request
Motor speed
Time
B
SSE completed
indication
1
6
5
SBC output
3
4
SBC.12
A
C
2
SSE state &
indication