ABB FSO-12, User Manual

Page: 93 / 388

Safety functions 93

SSE when drive modulation is lost during deceleration ramp
The behavior of SSE function in a situation where modulation is lost during
deceleration ramp is similar to SS1 function with ramp monitoring, see section
SS1
ramp functions when drive modulation is lost on page 74 .
Step Description
1 The SSE request is received (for example, from the I/O).
2 After time D has elapsed, the drive starts to ramp down the motor speed. SAR0
parameter
200.102 defines the deceleration ramp. The FSO starts the SAR0 ramp
monitoring (parameters SARx.11 and SARx.12 ).
3 The motor speed goes below the SBC speed limit (A), the FSO stops the SAR0
monitoring and activates the SBC function.
The FSO starts counters for times B and C.
Note : You can define an extra delay (parameter
SSE.16
, not shown in the figure)
before the FSO activates the SBC function. This affects also the STO activation (step
4).
3b If the motor speed hits a ramp monitoring limit, the FSO activates the STO function. See
section
Safe torque off (STO)
on page 55 for more information on how to configure
the STO function.
4 After time B has elapsed, the FSO activates the drive STO function.
5 The SSE request is removed.
6 After time C has elapsed, the FSO defines the motor as stopped, the SSE completed
indication goes on and the acknowledgement becomes allowed as soon as the SSE
request has been removed (step 5).
7 After the acknowledgement, the SSE, STO and SBC functions are deactivated and the
control is given back to the drive, which is allowed to modulate again. The indications
go off.