Valhalla Zeus User manual

Zeus
Turntable
Motor Speed
Controller /
Tachometer

1Product Overview ..................................................................................................3
2Installing and connecting the controller.................................................................3
2.1 Safety...............................................................................................................3
2.2 Overview.........................................................................................................4
2.2.1 Connecting the FFC ribbon cables...........................................................4
2.2.2 Basic installation overview –LP12 .........................................................5
2.2.3 Configuration menu and tuning software ................................................6
2.2.4 Configuration menus and parameters - introduction ...............................7
2.2.5 Setup Menu - item entry ..........................................................................7
2.3 Mounting the platter internal IR sensor –LP12..............................................7
2.4 Mounting OLED Display –LP12 .................................................................10
2.5 Adaptive Speed Control –PID......................................................................12
2.5.1 Turntable PID values .............................................................................12
2.5.2 Final installation note.............................................................................13
3Configuration menus and parameters ..................................................................14
3.1.1 Setup Menu - item entry ........................................................................14
3.1.2 System Parameters.................................................................................14
3.1.3 Motor Parameters...................................................................................16
3.1.4 PID Control parameters .........................................................................16
3.1.5 Test platter Sensor Trigger.....................................................................17
3.1.6 RequestedvsProgrammed Values...........................................................17
3.1.7 Write to eeprom .....................................................................................17
3.1.8 Motor ON/OFF ......................................................................................17
3.2 PID Tuning - Theory.....................................................................................18
3.3 Step response.................................................................................................19
3.4 Stability in the time domain..........................................................................19
3.4.1 Analysing step response plots................................................................20
3.5 Tutorial –Manually tuning from scratch ......................................................22
4Appendix - MAC Users.......................................................................................26
5Specifications.......................................................................................................28
6Manufacturer Details ...........................................................................................28

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. The following parameters may be
adjusted using configuration values defined and stored in the on-board
microprocessor: phase drive voltage, frequency and phase delay. Adjustable values
mean the user may adjust the parameters to achieve minimum motor vibration and
noise in their turntable which is highly desirable.
The microprocessor also incorporates a Proportional, integral and Derivative (PID)
control algorithm. By utilising an optical sensor to read the turntable platter rotation
speed and using the PID algorithm adjustment of the AC signals fed to the motor is
possible. The feedback loop created by the sensor and PID result in accurate speed
control and low WOW values and compensate for turntable wear and tear, also stylus
drag.
2 Installing and connecting the controller
2.1 Safety
WARNING: The Zeus motor controller MUST be installed inside a
turntable plinth that does not allow any physical contact with the Zeus
printed circuit board. Hazardous voltages exist on the printed circuit
board that may result in injury or death. If in doubt consult your dealer
who will be happy to install the controller board for you.
WARNING: Only ever connect a Laptop/PC USB connection via USB
cable routed out of your turntable plinth –do not operate the board
with the plinth baseboard removed as hazardous voltages exist within
the Zeus board.
INFORMATION: It is usual for the heatsinks to get hot during normal
operation typically 70-80 degrees centigrade.

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.
Figure 1 - Pictorial wiring for a 2 phase synchronous motor
The on/off/speed switch is a standby switch. The board may be configured to go into a
low power sleep state after a period of inactivity.
The procedure for installation is in two parts. Basic installation and adaptive PID
speed control.
2.2.1 Connecting the FFC ribbon cables
Slide the black retaining clip forward about 1.5mm away from the connector –this
will release the latch. When connecting the cable back the contacts face towards the
PCB. Slide the blue tab in and push the black retaining latch back so it clicks into
place. This will lock the FFC cable in place. When inserting the FFC cables the
contacts on the FFC cables always face the PCB.

2.2.2 Basic installation overview –LP12
1. Remove the turntable power cord from the mains supply, inner & outer platter,
arm counterweight and secure your tonearm with its retaining clip or use
masking tape to secure. To prevent oil leaking out the baring, ensure you tape
over the top of bearing or use a bung
2. Remove the platter base board.
3. Mount the Linn internal cross-brace using plastic stand-off clips. The Linn
bearing should be central in the large circular cut out on the Zeus PCB.
4. Connect the motor to the controller board using the Motor connector block.
The board has legends that should match RED, BLUE and GREY standard
motor colours. If your platter runs backwards the colour coding on your motor
does not match the Linn/Airpax standard so reverse the BLUE & RED wires.
5. If using the original Linn Valhalla switch and flexible cable attach to the black
connector marked LINN-PSW1 with the copper contacts uppermost. If using
the supplied switch remove the existing square LINN switch and replace with
the square switch/PCB assembly. You will need to angle the switch into the
hole –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.
7. Connect the supplied USB cable to the board Serial connector and route
outside the plinth using the mains power cable cut-out.
8. If you have purchased the OLED/Speed Sensor, route the cables for these
next. See section 2.3 and 2.4 for detailed instructions. Calibrate the sensor.
9. Replace the platter base board.
10. Connect the turntable to the mains supply.
11. Switch on depress the start switch briefly < 0.5 second. The platter should turn
now at 33.3 rpm. If all is fine test 45 rpm by depressing the switch until the

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. This section requires critical placement
and adjustment of the IR sensor which you will do after a brief overview of the
configuration menu and software.
2.2.3 Configuration menu and tuning software
It’s best to get your turntable platter spinning first without using the IR platter sensor
and PID control. The motor controller is pre-configured with a set of defaults that
assume you are using a 110v synchronous 2 phase motor. These defaults should get
you through the basic testing for the board.
To configure the board for basic testing use the PIDTuning application (or a serial
console application set to 9600,N,8,1). Interaction with the controller firmware is via
the serial command input and output area:
A configuration menu should be displayed upon initial connection. Note that in later
steps when PID tuning the menu will not display, however, you can always get the
menu to print by inputting the “M” character (not case sensitive) in the Serial Cmd:
Input area and pressing Enter/Return (CR). Any values that you input will remain in
place until power is removed unless you use the Write Current Values to EEPROM
option. On controller power up the EEPROM values are read back into the program.
Your Anti-Virus (AV) program may block the PIDTuning.exe program or show a
warning –this is normal as the program is not digitally signed. You may need to
create an exception in your AV software.

The PIDTuning app is only available on Windows. Although this program makes it
easier to tune the board PID parameters a standard serial console application may be
used on other platforms (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. -
introduction
The PIDTuning app is only available on Windows. Although this program makes it
easier to tune the board PID parameters a standard serial console application may be
used on other platforms (e.g. Mac/Linux) for board configuration. The board is
already pre-configured for LP12 users.
2.2.5 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. Either provide a new value within the range
specified or press the Return key (CR) to accept the current value. The section
questions will repeat until the Q key is pressed. The Q key can pre pressed at any
time, not just at the end of a section to exit the current setup menu. You must be back
at the main menu to save any settings to the EEPROM.
2.3 Mounting the platter internal IR sensor –LP12
For Linn LP12 turntables (or turntables with a large space under the platter) an
internal platter IR sensor mounting position is available. Route the 4 way FFC
connecting cable through the central bearing hole (or other available access point).
However, ensure there are no sharp edges to damage the insulation of the FFC cable.
Often the bearing bolt heads have sharp edges so endure the FFC cables are routed in
the spaces between the bolt heads.

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).
Position the IR sensor diodes to the outside of the platter. Use the supplied black label
approx. 10mm in width, and affix to the inside edge of the platter. Mount the IR
sensor close so that the transmitting and receiving diodes can register the passing of
the tape.

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. Hand rotate the platter and adjust the position the
speed box so that, each time the marker passes the trigger message is displayed. (Also
brief flash from the IR sensor registration indicator LED flashes –it may be possible
to see this light by reflection on the plinth top).
The trim pot location is accessed either through the top or underneath (depending on
the IR sensor supplied). Adjustment of the IR Sensor Trim pot may be required with a
small screwdriver.

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.
2.4 Mounting OLED Display –LP12
Route the 8 way FFC connecting cable through the central bearing hole (or other
available access point). However, ensure there are no sharp edges to damage the
insulation of the FFC cable. Often the bearing bolt heads have sharp edges so endure
the FFC cables are routed in the spaces between the bolt heads.
Position the OLED case outside of the outer platter wherever you find it aesthetically
pleasing. Lightly tack down the FFC cable. Use either double sided sticky tape or a
couple of small balls of blue/white tack to stick down the OLED case. Connect the
other end of the 8 way FFC cable to connector P1 on the underside of the motor
controller PCB (silver contacts towards the PCB).