ABB FSO-21, User Manual

Page: 115 / 540

Safety functions 115
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SSE with immediate STO, with speed limit activated SBC
This safety function requires that you use an encoder in the safety application.
The operation of the SSE with immediate STO with speed limit activated SBC is
described in the time diagram and table below. For configuration, see section
How to
configure STO with speed limit activated SBC on page 337 .
A STO SBC speed (parameter SBC.14 ): Speed limit at which the FSO activates the SBC
function (brake).
B 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.
Step Description
1 The SSE request is received (for example, from the I/O). The FSO activates the drive
STO function. SSE active indication
SSE output ( SSE.21 ) and STO output ( STO.21 )
go on.
2 The motor speed goes below the SBC speed limit (A) and the FSO activates the SBC
function (brake).
3 The motor speed reaches the zero speed limit (B), 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 4).
4 The SSE request is removed.
5 After the acknowledgement, the STO, SSE 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
SSE completed
indication
1
5 4
SBC output
2
B
3
A
SSE state &
indication