8 Troubleshooting8-288.4 Troubleshooting Malfunction Based on Operation andConditions of the ServomotorTroubleshooting for the malfunctions based on the operation and conditions of the servomotor is provided inthis section.Problem Probable Cause Investigative Actions Corrective ActionsServomotor DoesNot StartThe control power supply is notON.Check voltage between controlpower terminals.Turn OFF the servo system. Correctthe wiring so that the control powersupply turns ON.The main circuit power supply isnot ON.Check the voltage between maincircuit power terminals.Turn OFF the servo system. Correctthe wiring so that the main circuitpower supply turns ON.Wiring of I/O signal connector CN1is faulty or disconnected.Turn OFF the servo system. Checkif the connector CN1 is properlyinserted and connected.Correct the connector CN1 connec-tion.Wiring for servomotor main circuitcable or encoder cable is discon-nected.Check the wiring. Turn OFF the servo system. Correctthe wiring.Overloaded Run under no load and check theload status.Turn OFF the servo system. Reduceload or replace with larger capacityservomotor.Encoder type differs from parame-ter setting (Pn002.2).Check the settings for parameterPn002.2.Set parameter Pn002.2 to theencoder type being used.Settings for the input signal selec-tions (Pn50A, Pn50B and Pn511) isincorrect.Check the settings for parametersPn50A, Pn50B and Pn511.Correct the settings for parameterPn50A, Pn50B and Pn511.SV_ON command is not sent. Check the command sent from thehost controller. Send the SV_ON command.SENS_ON command is not sent. Check the command sent from thehost controller.Send the commands to the multi-winding drive unit in the correctsequence.The forward run prohibited (P-OT)and reverse run prohibited (N-OT)input signals are turned OFF.Check P-OT or N-OT input signal. Turn P-OT or N-OT input signalON.The safety input signal (/HWBB1 or/HWBB2) remains OFF.Check the /HWBB1 and /HWBB2input signal.Set the /HWBB1 and /HWBB2input signal to ON.When not using the safety function,mount the safety function jumperconnector (provided as an acces-sory) on the CN8.The brake is not released. Check the operation of the brake. Release the brake.A fault occurred in the SERVO-PACK or converter. −Turn OFF the servo system.Replace the SERVOPACK or con-verter.ServomotorMovesInstantaneously,and then StopsServomotor wiring is incorrect. Turn OFF the servo system. Checkthe wiring. Correct the wiring.Encoder wiring is incorrect. Turn OFF the servo system. Checkthe wiring. Correct the wiring.ServomotorSpeed UnstableWiring connection to servomotor isdefective.Turn OFF the servo system. Checkconnections of power line (phasesU, V, and W) and encoder connec-tors.Tighten any loose terminals or con-nectors and correct the wiring.ServomotorRotates WithoutReference InputA fault occurred in the multi-wind-ing drive unit or SERVOPACK. −Turn OFF the servo system.Replace the multi-winding driveunit or SERVOPACK.
