37 Trouble-Shooting
The following table should be understood as a "First-aid" box. There may be a wide variety of causes of any
fault that occurs, depending on the conditions in your system. In multi-axis systems there may be further hidden
causes of a fault.
Our applications department can give you further assistance with problems.
Fault Possible causes Measures to remove the cause of the fault
Fault message
communication fault
— wrong cable used
— cable plugged into wrong socket of
the servo amplifier or PC
— wrong PC interface selected
— use a null-modem cable
— plug the cable into the correct
socket of the servo amplifier or PC
— select the correct interface
Motor doesn't rotate
— amplifier disabled
— analog setpoint failed
— Motor phases swapped
— Brake not released
— drive is mechanically blocked
— Motor pole number set incorrectly
— Feedback set up incorrectly
— current limit activated (analog or digital I/O)
— apply enable signal
— check PLC-program and cable
— correct motor phase sequence
— check cable and inverse diode
— check drive
— correct setting
— correct feedback setting
— correct current limitation
Motor oscillates
— Gain KP too high
— Interference in feedback system
— Analog-GND (AGND) is not
connected with the analog setpoint sources
— reduce KP (speed contr.)
— replace the feedback cable
— connect AGND with setpoint
source
Motor runs too soft
— Integral time Tn too high
— Gain KP too low
— PID-T2 too high
— T-Tacho too high
— reduce Tn (speed contr.)
— increase KP (speed contr.)
— reduce PID-T2
— reduce T-Tacho
Motor runs roughly
— Integral time Tn too low
— Gain KP too high
— PID-T2 too low
— T-Tacho too low
— increase Tn (speed contr.)
— reduce KP (speed contr.)
— increase PID-T2
— increase T-Tacho
Setup Software 95
BECKHOFF 07/03 Trouble-Shooting
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