ABB FSO-21 - Page 169

Safety functions 169
SSE with immediate STO, with an encoder
This applies when the SSE function has been configured as “Immediate STO” and an
encoder is used.
A SLS trip limit positive (parameter SLSx.14, SLSx.23, SLSx.33 or SLSx.43)
B SLS limit positive (parameter 200.23, 200.33, 200.43 or 200.53)
C Response time (depends on system configuration, see page 532)
D Zero speed limit (parameter FSOGEN.52): Speed limit to define the motor as stopped.
The safety function is completed and the SSE completed indication (parameter SSE.22)
goes on. The acknowledgment becomes allowed.
SLS trip limit (A)
Step Description
1 The SLS request is received, the motor speed is below the SLS limit positive (B) and
the FSO starts the SLS monitoring. The SLS indication (parameter SLSx.15, SLSx.24,
SLSx.34 or SLSx.44) goes on.
2 The motor speed goes above the SLS limit positive (B).
3 The motor speed reaches the SLS trip limit positive (A). The SLS active indication goes
off.
4 After time C, the FSO activates the SSE function, opens the drive STO circuit and the
motor coasts to a stop.
5 The motor speed goes below the SLS limit positive (B). The SLS indication goes on.
6 The motor speed reaches the zero speed limit (D). The motor has stopped and the
SSE completed indication goes on.
7 The SLS request is removed. The SLS monitoring is still on (acknowledgement method
is manual or from a safety PLC).
8 The SLS function is acknowledged and the FSO stops the SLS monitoring. The SSE
function is acknowledged with the same acknowledgement. The indications go off.
SLS indication
SLS request
Motor speed
Time
A
8
1
B
4
3
D
C
SSE state &
indication
5
SSE completed
indication
2
7
6
- -> Safe stop emergency (SSE)