Drive Modulation Loss When Encoder Feedback Is Used; Operation Principle Diagram - ABB ACS880-07 User Manual

Motor speed
A
B
A SSM1 limit positive (parameter SSMx.13)
B SSM1 limit negative (parameter SSMx.12)
1. The motor speed goes above the SSM limit positive. The SSM indication goes off.
2. The motor speed goes below the SSM limit positive. The SSM indication goes on.
3. The motor speed goes below the SSM limit negative. The SSM indication goes off.
4. The motor speed goes above the SSM limit negative. The SSM indication goes on.
￭

Drive modulation loss when encoder feedback is used

In the case when drive modulation is lost during the safe deceleration ramps and motor
speed does not decelerate within monitoring limits due to coasting, FSO generates a
monitoring limit hit indication and activates STO based on measured motor speed when
encoder feedback is used with FSO-21 and FSE-31 for functional safety purposes in the
following situations:
• SAR1 ramp monitoring with SS1, SLS or SDI functions
• SAR0 ramp monitoring with SSE function as Emergency ramp
• time monitored ramp with any of previously mentioned safety functions.
Note: Parameters SLSx.05 and SLSx.06 are not used when FSO-21 is using encoder
feedback. If feedback change from encoder to estimate is allowed with parameter
S_ENCGEN.11, SLSx.05 and SLSx.06 become relevant if encoder fails and FSO switches
to use speed estimate configuration.
￭

Operation principle diagram

This diagram shows the connections of the FSO module. The figure shows a simplified
operation principle. For a more detailed description, see the circuit diagrams delivered with
the drive.
3
1 2
Option description 29
Time
4
SSM indication