User guide

Publication 8720MC-IN002A-EN-P — December 2002
Troubleshooting Your 8720MC Servo Drive 3-5
DriveOvertempFault
(A1: Overtemp)
A drive heat sink temperature has exceeded
the specified limit.
/ Regen stop
• Check the cabinet filters, drive fans and heat sinks.
• Check the thermal sensor and sensor wiring.
• Reduce the load or duty cycle.
MotFeedbackFault
(A1: Fdbk 1 Loss)
The motor encoder feedback signal has been
lost.
/ Disable stop: the drive will disable and the
motor will coast to a stop with an error
message on the HIM. The control board
status LED will be flashing and the drive OK
output will be open.
• Make sure the feedback wires are firmly crimped on
the 8720MC mating feedback connector.
• Check the MS motor feedback connector.
• Check the encoder connector inside the motor.
• Check for wire breaks in the feedback cable.
• Make sure encoder power is available on P1-6.
• If all connections are verified and encoder power is
available and encoder output is still not present -
replace motor.
AuxFeedbackFault
(A1: Fdbk 2 Loss)
The auxiliary encoder feedback signal has
been lost. SERCOS configuration only.
/ Disable stop
• Make sure the feedback wires are firmly crimped on
the 8720MC mating feedback connector.
• Check the MS motor feedback connector.
• Check the encoder connector inside the motor.
• Check for wire breaks in the feedback cable.
• Make sure encoder power is available on P1-19 or
P1-20.
• If all connections are verified and encoder power is
available and encoder output is still not present -
replace motor.
MotFeedbackFault
(A1: Fdbk 1 AQB)
A feedback counting error has occurred on
the motor feedback interface.
Electromagnetic interference is the probable
cause.
/ Disable stop
• Check that the feedback cable braided shield is
firmly bonded to the drive chassis via the shield
clamps.
• Make sure the feedback and motor cables
recommended in the 8720MC High Performance
Drives Installation Manual (publication
8720MC-IN001x-EN-P) are being used.
• Make sure the shield and drain wire for the motor
cable is securely bonded to the drive chassis. Make
sure 4 wire shielded motor cable is being used and
that the ground wire is connected to drive PE ground.
• If the recommended cable is being used and all
shields are tied to earth ground replace the motor.
AuxFeedbackFault
(A1: Fdbk 2 AQB)
A feedback counting error has occurred on
the motor feedback interface.
SERCOS configuration only
/ Disable stop
• Check that the feedback cable braided shield is
firmly bonded to the drive chassis via the shield
clamps.
• Make sure the feedback and motor cables
recommended in the 8720MC High Performance
Drive Installation Manual (publication
8720MC-IN001x-EN-P)
are being used.
• Make sure the shield and drain wire for the motor
cable is securely bonded to the drive chassis. Make
sure 4 wire shielded motor cable is being used and
that the ground wire is connected to drive PE ground.
• If the recommended cable is being used and all
shields are tied to earth ground replace the motor.
OverSpeedFault
(A1: Overspeed)
The maximum commanded motor speed has
exceeded the maximum allowable motor
speed.
/ Disable stop
• Check the velocity limit parameters for the active
parameter set against parameter 113, max motor
speed.
• Check parameter 695, the analog scale factor
DriveHardFault
(Memory Init)
Control board hardware Failure Fatal error - replace control board
Fault Message RSLogix
(HIM)
Probable Cause/Drive Response Corrective Actions