Baldor MN1903 Servo axis tuning for current control, Selecting servo loop gains

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5.5 Servo axis - tuning for current control

5.5.1 Selecting servo loop gains

All servo loop parameters default to zero, meaning that the demand output will be zero at power up. Most servo amplifiers can be set to current (torque) control mode or velocity control mode; check that the servo amplifier will operate in the correct mode. The procedure for setting system gains differs slightly for each. To tune an axis for velocity control, go straight to section 5.7. It is recommended that the system is initially tested and tuned with the motor shaft disconnected from other machinery.

Note: The method explained in this section should allow you to gain good control of the motor, but will not necessarily provide the optimum response without further fine-tuning. Unavoidably, this requires a good understanding of the effect of the gain terms.

1.In the Toolbox, click the Fine-tuning icon.

The Fine-tuning window is displayed at the right of the screen. The main area of the WorkBench v5 window displays the Capture window. When tuning tests are performed, this will display a graph representing the response.

2.In the Fine-tuning window, click in the KDERIV box and enter a starting value of 1.

Click Apply and then turn the motor shaft by hand. Repeat this process, slowly increasing the value of KDERIV until you begin to feel some resistance in the motor shaft. The exact value of KDERIV is not critical at this stage.

5-16 Operation

MN1903

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Contents NextMove PCI Motion Controller Page Contents Operation Appendices Iv Contents MN1903 General Information Safety Notice PrecautionsNextMove PCI features MN1903 IntroductionIntroduction MN1903 Identifying the catalog number InstalledReceiving and inspection Catalog number PCI001Phase Units and abbreviationsHardware requirements Other information needed for installationIntroduction Tools and miscellaneous hardwareLocation requirements Installing the NextMove PCI card InstallationThis completes the basic installation NextMove PCI Expansion card and can Bracket boardBasic Installation MN1903 100-pin edge connector Outline1 100-pin connector pin assignment Pin Signal100-pin connector pin assignment Analog I/O Location Analog inputsPin Name MintMT keyword / description Analog input wiring, AIN0 shown Analog outputs Drive Demand/Command Pin Name DescriptionDigital I/O Input Common Breakout module connectorDigital input arrangement Stepperio Digital inputs Pin Name MintMT keyword Common DescriptionINX.4 Digital input circuit fast interrupts Digital outputs OUTX.0 Other I/O Encoder interfaces X12, X13, X14, X15Encoder input frequency Power Relay and can power Relay connectionsStepper drive outputs X10 Pin X10 Name X11 Name DescriptionCan Connections Cable length Maximum bit Resistance Conductor Rate Area1 CAN1 CANopen Baldor proprietary can interface using a RJ45 connector 2 CAN2 Baldor canEmulator connection Reset statesSystem watchdog Connection summary minimum system wiring Example minimum system wiringConnector details for minimum system wiring shown in Figure This completes the input/output wiringModule Signal Connector Breakout Pin Name FunctionInput / Output MN1903 Installing the driver software Windows 95, 98 and ME Drivers\nmPCI\win9xInstalling the driver software Windows NT Installing the driver software WindowsInstalling WorkBench \startStarting WorkBench MN1903 Operation Operation MN1903 WorkBench Help fileChoosing an axis 1, 2, 3 and 4 axis cards Configuring an axisChoosing an axis 8 axis card Selecting a scale Setting the drive enable output Testing the drive enable output Servo axis testing and tuning Testing the drive command outputAn introduction to closed loop control Summary, the following rules can be used as a guide NextMove PCI servo loop Servo axis tuning for current control Selecting servo loop gainsMN1903 Operation Underdamped response Underdamped responseOverdamped response Overdamped responseCritically damped response Critically damped ideal responseServo axis eliminating steady-state errors Servo axis tuning for velocity control Calculating KvelffKvelff Correct value of Kvelff Adjusting Kprop Correct value of Kprop Stepper axis testing JOG.0=2Digital input/output configuration Digital input configurationDigital output configuration Saving setup information 10.1Loading saved information Operation MN1903 Problem diagnosis SupportMet featureNextMove PCI indicators Status and can LEDsCommunication Symptom CheckMotor control Output polarity Mechanical specifications Digital inputs X1 Relay output Encoder interfaces X1210CANopen interface Stepper outputs X1011Baldor can interface NextMove PCI Expansion card NextMove PCI Expansion cardWith no One 4-axis One 8-axis Two 4-axis Axis numbering when using expansion cardsMain Expansion cards Expansion Expansion cardExpansion card status LEDs CBL021-501 NextMove PCI Breakout moduleCatalog number Description PCI003-501 CBL021-503Spares Digital output modulesNextMove PC system adapter Catalog Description Number OPT025-508Baldor can nodes Catalog Description Number OPT008-501 NextMove PCI can Bracket boardEncoder Splitter/Buffer board OPT029-501Accessories MN1903