Chapter 4 Troubleshooting - 81 -General Drive I/OFor problems with the drive function of the Axis I/O, check the followingconfigurations.1. If the drive will not enable, verify that the drive’s fault outputconfiguration is correct (Gemini command, OUTLVLx1, etc.). See alsoAcroBASIC flag, Enable Drive I/O.2. If the axis status LED turns red when the drive is disabled, verify that thedrive’s fault output configuration is correct (Aries command, FLTDSB0,etc.). Note: Some drives will indicate a drive fault when disabled, andcause the axis status LED to illuminate red.Servo AxesFor problems with the servo axes, use the following procedures.1. If the servo is stable, but the direction of motion is reversed, both thefeedback cabling and commanded Drive AOUT signals are reversed.Use either: AcroBASIC remedy (not applicable for SSI feedback devices):Change the polarity of both the DAC GAIN and MULT settings.This reverses both the polarity of the commanded direction andthe feedback direction so that servo stability is maintained. Hardware remedy: Switch the Drive AOUT+ and Drive AOUT−connection to the drive. (If the drive does not support differentialoutputs, this will not work.) You must also change the feedbackwiring or mounting so that it counts in the same direction as thecommanded direction. Depending on the feedback device used,do one of the following: If your application can change how the feedback device ismounted, you may be able to affect the count direction with it. For Quadrature feedback, switch Encoder CHB+ and EncoderCHB− between the controller and the feedback device. For Step and Direction feedback, switch Encoder CHB+ andEncoder CHB− between the controller and the feedbackdevice. For CW and CCW feedback, switch both the CW and CCWsignal pairs between the controller and the feedback device. For SSI feedback, switch the Drive AOUT+ and Drive AOUT−connection between the controller and the drive. (If the drivedoes not support differential outputs, switching the connectionswill not work.) Note: Some SSI encoders may have a polarityinput that can be set to change the count direction.2. If the servo is unstable, check for the conditions listed below and followthe recommended steps. The drive and motor combination are not properly tuned; refer tothe drive installation manual for proper tuning. Verify that you have attached the axis as a servo and not astepper. For more information, see the ATTACH command in the
