Parker BD-E Series Manual

Contents

Parker BD-E Series Manual Manual pdf 41 page image

APPENDIX A. ENCODER SETUP 35Appendix A. ENCODER SETUPIntroductionThis section is applicable when the BD drive is not used with Digiplan MD Series motors.BD drives are designed to operate with 3-phase brushless servo motors which have both acommutation encoder (Hall effect encoder) and an incremental encoder fitted. The commutationencoder must have Com A leading Com B by 120° electrical and Com B leading Com C by 120°electrical, and must have the same pole count as the motor. The incremental encoder musthave 512 or 1024 lines, with A+ leading B+ for clockwise (CW) motor rotation. The I+ output is ahigh going pulse that occurs when A+ and B+ are high and is shorter than one complete cycle ofA+ (see Table 3-1 waveform diagram).CommutationWhen power is first applied to the drive, the commutation encoder is used to establish a torqueangle of approximately 90° electrical, so that 87% smooth motor torque can be achievedimmediately. Once the motor has moved through 180° electrical, it will have passed an edge ofCom A, achieving a more accurate setting of the torque angle, allowing 95% torque to beobtained. Following a complete revolution, the motor will have received an index pulse whichprovides the most accurate position information allowing 100% torque to be applied. The indexpulse also acts as a continual check on the electrical position.Encoder SetupWhen setting up the encoders, disconnect the motor cable from the drive, but leave the encodercable connected and the drive powered up but de-energised. Select any motor phase, say 'u' inFigure A-1, and take it to the negative connection of a DC power supply, as shown. Connect theother two motor phases to the power supply positive connection via power diodes.+ve-veDC PSUU phaseFigure A-1. Encoder Set-up Circuit