ABB ACS880-17, User Manual

Page: 18 / 58

18 Option description and instructions
Operation principle
The operation and configuration of the Emergency stop function is slightly different with
and without a safety encoder. Only the FSO-21 module supports the safety encoder
interface, and you can also use it without a safety encoder.

Time schemes without a safety encoder
Emergency stop, stop category 0
This time scheme diagram illustrates the operation of the Emergency stop, stop category 0
safety function. This option uses the Safe torque off (STO) function of the FSO module.
For more information, see the FSO module user’s manual.
A Time to zero speed: Time from the activation of the STO function to the moment when the STO
function is completed. The indication lamp goes on.
The user must set this time longer than the time
the motor coasts from the maximum speed to zero speed (parameter STO.14 Time to zero speed
with STO and modoff ).
B Restart delay: Delay from pushing the emergency stop button (and activation of the STO function) to
the moment that the user can push the reset button at the earliest (and acknowledge the STO
function). With this parameter, it is possible to allow a restart of the drive while the motor is still
running (fly-start) (parameter
STO.13 Restart delay after STO ).
Step Description
1 The user pushes the emergency stop button and the FSO module activates the FSO and drive STO
functions. The FSO module starts counters for times A and B.
Note : The safety function request to the FSO module must be active for at least 20 ms.
2 The user releases the emergency stop button.
3 Time B has elapsed. The user can push the reset button, that is, acknowledgement of the STO
function is possible even though the motor is still running. (In this example, the user pushes the reset
button in step 5.)
4 Time A has elapsed. The motor has stopped and the emergency stop indication lamp goes on.
5 The user pushes the reset button (this resets the emergency stop circuit and removes the emergency
stop request from the FSO module).
Note : The pressing time of the reset button must be between 0.3 s...3 s.
Time
Motor speed
1 4 5
E-stop button
(STO request)
Drive STO
status
Reset button
A
Indication lamp
STO.13
6
B
STO.14
2
3