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Valhalla Zeus User Manual

Turntable motor speed controller / tachometer
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Zeus
Turntable
Motor Speed
Controller /
Tachometer

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Summary of Contents for Valhalla Zeus

  • Page 1 Zeus Turntable Motor Speed Controller / Tachometer...

  • Page 2: Table Of Contents

    Product Overview ....................3 Installing and connecting the controller ..............3 Safety ....................... 3 Overview ......................4 2.2.1 Connecting the FFC ribbon cables ............4 Basic installation overview – LP12 ............5 2.2.2 2.2.3 Configuration menu and tuning software ..........6 2.2.4 Configuration menus and parameters - introduction .......

  • Page 3: Product Overview

    1 Product Overview The Zeus motor controller is a sub assembly intended for incorporation into an audio HiFi turntable to provide necessary drive signals to the originally installed turntable 24 pole AC 115v synchronous motor. The Zeus provides two independent AC signals for each phase of the AC synchronous motor.

  • Page 4: Overview

    2.2 Overview The Zeus board may be mounted inside the LP12 turntable on a Linn (or compatible) cross brace. The minimum connections are mains power and motor wiring. It’s possible to operate the board with just these two connections, however, most users will want the start/33/45/stop switch, the OLED display and IR sensor for adaptive (PID) speed control.

  • Page 5: Basic Installation Overview - Lp12

    – it will be a snug fit. Connect the FFC cable to PSW1 (underneath the black LINN-PSW1 connector) with the contacts facing towards the PCB. 6. Connect the mains supply cord to the Zeus to either the 230v or 115v connections as appropriate for your geography.

  • Page 6: Configuration Menu And Tuning Software

    LED flashes. (Approx. 3 seconds). You can switch back to 33.3 by depressing the switch until the LED flashes. 12. To go into standby, depress the switch for approx. 1 second. If the controller works without issues and you have purchased the Speed Sensor move on to the adaptive speed control (PID) step.

  • Page 7: Configuration Menus And Parameters - Introduction

    (e.g. Mac/Linux) for board configuration. Mac users may need to install drivers to interface correctly with the Zeus – consult section 4 2.2.4 A full list of all the menu options and the default values has been provided in section 3Error! Reference source not found.
  • Page 8 Position the IR sensor towards the inside edge of the outer platter. Lightly tack down the FFC cable for the positioning test. Use either double sided sticky tape or a couple of small balls of blue/white tack to stick down the IR sensor lightly. Connect the other end of the 4 way FFC cable to connector P3 on the underside of the motor controller PCB (silver contacts towards the PCB).
  • Page 9 WARNING: Do not connect your turntable to the main supply at this stage. With the motor controller powered up on Laptop/PC only, use the PIDTuning app and choose option 4 from the menu. This will display a message on the terminal area each time the IR sensor is triggered.

  • Page 10: Mounting Oled Display - Lp12

    Finally tape the FFC down so it does not rub against the inner platter and press the IR sensor firmly into its final place. You can optionally secure the IR sensor more permanently by using the supplied double sided tape. Once a reasonably accurate rpm indication is obtained you can move onto setting up PID control and tuning the parameters.

  • Page 12: Adaptive Speed Control - Pid

    2.5 Adaptive Speed Control – PID Once you have the controller board installed and providing basic 33.3 or 45 rpm operation; the IR sensor is installed, adjusted and correctly displaying the platter RPM to a reasonable degree of accuracy (i.e. around 33 or 45 rpm) then you are ready to enable PID control.

  • Page 13: Final Installation Note

    2.5.2 Final installation note Congratulations you have installed the controller. There are many configuration options and items in the controller that you can tweak and adjust to your specific turntable. Please feel free to read through section 3 for a full explanation of all of the parameters.

  • Page 14: Configuration Menus And Parameters

    3 Configuration menus and parameters 3.1.1 Setup Menu - item entry When in each of the menu items you will be asked to respond to a question. For example: “Enter 33.3 rpm frequency, Hz: (45 – 65): 50.0”. The question will be followed by the units, the range of acceptable values in between the brackets (45 - 65), and finally the current value: 50.0.
  • Page 15 the power switch. Display blank time, min: 0-360 Time for the display to blank after starting or changing speed. 0 disables feature. Are you using PID and platter sensor? Y / N Have you mounted an IR speed sensor and connected it to the board.

  • Page 16: Motor Parameters

    3.1.3 Motor Parameters Configuration items in this menu relate to the motor and turntable. Parameter / Description Units Range Default value Winding 1 phase is always starts at 0 degrees. This is a statement. Subsequent windings probably require 90, 180, 270 degree phase angles respectively depending if you are using 2,3,4 phase motors.

  • Page 17: Test Platter Sensor Trigger

    Parameter / Description Units Range Default value Enter Kp: Value for proportional term (up to 6 decimal places) Enter Ki: 0.31 Value for term (up to 6 decimal places) Enter Kd: 0.191 Value for derivative term (up to 6 decimal places) Enter Motor frequency to rotation ratio: 0.66666 (to7 decimal places).

  • Page 18: Pid Tuning - Theory

    3.2 PID Tuning - Theory The following explanation of PID theory will help you to understand the control system and common terms that are used. Proportional Gain (Kp)—Proportional gain is the system stiffness. It determines the contribution of restoring force directly proportional to the position error. Restoring force is comparable to a spring in a mechanical system.

  • Page 19: Step Response

    0 rpm to 33.3 rpm or 33.3 rpm to 45 rpm. The system is the combination of the Zeus motor controller, your motor, belt, pulley and platter. To view your system’s step response, use the PIDTuning application, connect the serial port and click the Start button.

  • Page 20: Analysing Step Response Plots

    Commanded Position—the desired position (or rotation speed). In this case, the commanded value is 1,000. For the Zeus motor controller this will be the value in Hz for 33.33 rpm or 45 rpm. Steady-State Position Error—the error that occurs when the system is at rest.
  • Page 21 An over-damped system produces a smoother, slower step response. An over-damped system is characterized by no overshoot, and long rise and settling times. An under-damped system produces a slight oscillatory response that eventually dampens out. An under-damped system is characterized by a large overshoot, a long settling time, and short peak and rise times.

  • Page 22: Tutorial - Manually Tuning From Scratch

    An oscillatory system response produces a constant-amplitude, continuous-position oscillation. An oscillatory system is characterized by infinite settling times. 3.5 Tutorial – Manually tuning from scratch You will need to use the Windows PIDTuning application to change your coefficients. With the application connected after hitting the start button you can see the reaction of your system to changes in parameters on the graph.
  • Page 23 5. Repeat steps 3 and 4 until you achieve a reasonable value for Kp. For most systems, this will mean that the response will approach the set point, and overshoot by 1 or 2 peaks about the with a reasonable amount of dampening. This steady state value may be slightly offset from the set point value, and this offset can be corrected with an appropriate Ki value later.
  • Page 24 quickly without any offset. Observing the WOW value until it gets to a stable < 0.1 or less is a good indicator. In the example below that’s after about 13 seconds. 10. Make a note of your Kp, Ki and Kd values. Set Os% to 5 and click Send. Next use the Auto Zoom feature and observe the running state.
  • Page 25 13. If necessary run a fine tune process for Kp, Ki and Kd to achieve optimum results. 14. Finally use the Save button to write the values to the EEPROM. Please send an email with your Make & Model of turntable and the optimum values of Kp, Ki and Kd and settling time to <0.1 WOW so we can build up a database of common turntables.

  • Page 26: Appendix - Mac Users

    4 Appendix - MAC Users Mac users will need to install USB drivers to connect to the Zeus motor controller. You can download and install from here: https://github.com/ledongthuc/example/blob/master/file/CH34x_Install_V1.3.zip If you do not have a serial monitor program use the one build into the Arduino IDE.

  • Page 28: Specifications

    T500mA 250v Dimensions 20 x 165 x 100mm (HxWxD) Motor Output drive voltage 12v to 110v AC Motor Output drive current 20mA Frequency resolution 0.001Hz <1% 6 Manufacturer Details S.Cobham T/A Valhalla Electronics 50 Chester Road Churchtown Southport PR9 7HD...

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