Fault
Cause
Remedy
F7452: Following error too
high
Reaction: OFF1
Acknowledgement: IMMEDI‐
ATELY
The difference between the position set‐
point position actual value (following error
dynamic model) is greater than the toler‐
ance.
● The drive torque or accelerating
capacity exceeded.
● Position measuring system fault.
● Position control sense incorrect.
● Mechanical system locked.
● Excessively high traversing velocity or
excessively high position reference
value (setpoint) differences.
Check the causes and resolve.
F7801: Motor overcurrent
Reaction: OFF2
Acknowledgement: IMMEDI‐
ATELY
The permissible motor limit current was ex‐
ceeded.
● Effective current limit set too low.
● Current controller not correctly set.
● Motor was braked with an excessively
high stall torque correction factor.
● Up ramp was set too short or the load
is too high.
● Short-circuit in the motor cable or
ground fault.
● Motor current does not match the
current of Motor Module.
● Reduce the stall torque correction factor.
● Increase the up ramp or reduce the load.
● Check the motor and motor cables for short-
circuit and ground fault.
● Check the Motor Module and motor
combination.
F7802: Infeed or power unit
not ready
Reaction: OFF2
Acknowledgement: IMMEDI‐
ATELY
After an internal power-on command, the
infeed or drive does not signal ready be‐
cause of one of the following reasons:
● Monitoring time is too short.
● DC link voltage is not present.
● Associated infeed or drive of the
signaling component is defective.
● Ensure that there is a DC link voltage. Check
the DC link busbar. Enable the infeed.
● Replace the associated infeed or drive of the
signaling component.
F7815: Power unit has been
changed
Reaction: NONE
Acknowledgement: IMMEDI‐
ATELY
The code number of the actual power unit
does not match the saved number.
Connect the original power unit and power up
the Control Unit again (POWER ON).
F7900: Motor blocked/speed
controller at its limit
Reaction: OFF2
Acknowledgement: IMMEDI‐
ATELY
The servo motor has been operating at the
torque limit longer than 1s and below the
speed threshold of 120 rpm .
This signal can also be initiated if the speed
actual value is oscillating and the speed
controller output repeatedly goes to its limit.
● Check whether the servo motor can rotate
freely or not.
● Check the torque limit.
● Check the inversion of the actual value.
● Check the motor encoder connection.
● Check the encoder pulse number.
SINAMICS V70 faults and alarms
7.2 Common faults and alarms
Diagnostics Manual
Diagnostics Manual, 06/2015, 6FC5398-6DP10-0BA2
541
