Sdi Trip Limit Hits - ABB FSO-21 User Manual

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SDI trip limit hits

This applies to SDI trip limit hit situations, that is, when the motor rotates too much to
the forbidden direction while the SDI monitoring is on. The SDI positive function is
used as an example.
Note: This diagram shows the position of the motor axle (not the motor speed).
Motor axle
position
1
A SDI tolerance limit degree (parameter SDI.14): The motor axle cannot move to the
forbidden direction more than defined with this parameter.
SDI monitoring limit
Step Description
1 The SDI positive request is received (for example, from the I/O) and the FSO starts the
SDI monitoring. The SDI indication goes on. The motor rotates to the correct direction
(in this case, positive).
2 The motor stops.
3 The motor starts to rotate again (into the positive direction).
4 The rotation direction of the motor changes to the forbidden (negative) direction. The
FSO locks the SDI tolerance limit (A) into its current position.
5 The SDI tolerance limit (A) is reached. The FSO stops the SDI monitoring and activates
the SSE function and the motor coasts to a stop. The SDI indication goes off. The SSE
indication goes on. See section
information on how to configure the SSE function.
6 The motor has stopped. The SSE function is completed and the FSO starts the SDI
monitoring. The SDI indication goes on and the SSE indication goes off.
When the motor starts to rotate again (into the correct direction), the SDI monitoring
continues with the original SDI tolerance limit (A).
3
2
Safe stop emergency (SSE)
- -> Safe stop emergency (SSE)
5 6
4
Safety functions 157
A
Time
SDI request
SDI state &
indication
SSE state &
indication
on page 93 for more