ABB FSO-21 - SSE When Drive Modulation Is Lost During Deceleration Ramp

Safety functions 139
 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 104.
Step Description
1 The SSE request is received (for example, from the I/O). SSE active indication SSE
output (SSE.21) goes on.
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 activates the SBC
function.
The FSO starts a counter for time 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 67 for more information on how to configure the
STO function.
4 After time C has elapsed, the FSO activates the drive STO function. STO active
indication parameter STO output (STO.21) goes on when STO is activated.
5 The motor speed reaches the zero speed limit (B), the FSO defines the motor as
stopped and stops the SAR0 monitoring. The SSE completed indication goes on and
the acknowledgement becomes allowed as soon as the SSE request has been
removed (step 6).
6 The SSE request is removed.
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
SSE output (SSE.21), SSE completed output (SSE.22), and STO output (STO.21) go
off.