Archive for May, 2008

Spindle Motor Controller

Friday, May 30th, 2008

This OZO has a spindle motor, with a proprietery controller card.  This evening I took the first stab at trying to reverse engineer this circuit card.  From my research so far, I think that it may be possible.  There are 8 output devices all appear to be the same 32N20E, these are 32Amp 200Volt Power FETS, WOW!

There is an LS7262 brushless motor controller chip and a 555 timer which may provide the oscillator input for the servo controller chip.

This is a picture of the Board with the IO pins labled:

Close up of the Board with Pins Labled

Pin out:

The bottom right 5 card edge connectors seem to be associated with the output drive to the motor.

1A Power for the motor (Probably High Voltage like 30 Volts)

2A Fat Trace to FET Bank 4

3A Fat Trace to FET Bank 3

4A Fat Trace to FET Bank 2

5A Fat Trace to FET Bank 1

6A Ground (Also connects to 1B)

The upper card edge connector appears to be IO for the LS7262 Chip

1B Ground (Also connects to 6A)

2B Connects to S1 on LS7262 (PIN 15)

3B Connects to S2 on LS7262 (PIN 16)

4B VSS which is actually V+ for the LS7262 (PIN 11)

5B Brake of the LS7262 (PIN 9)

6B -V of the LS7262 (PIN 18) Also connects to the CS1 and CS2 and Ground

7B VTRIP of LS7262 (PIN 13)

8B FWD/REV of LS7262 (PIN 19)

9B ENABLE of LS7262 (PIN 10)

10B V+ also goes through Pot to open jumper pin to CS1

It will take some more reading of the data sheet to figure out what signals EMC needs to send to control the servo.  It seems like it revolves around the Vtrip pin as far as speed control.  That pin seems to go to one of the IO pins on the other proprietery card.  It will take some more time to begin to understand that card.  I thought that it was mainly centered around the  encoders and limit switches, now I am beginning to question that assumption.

Its nice to think there may at least be hope of getting the existing orginal spindle going again.  We shall see…

Tuning the Machine

Thursday, May 29th, 2008

OK, now to get the OZO purring like it otter…

First I visited EMC Wiki and followed the latency test directions.

These directions are basically the same ones in the integrators manual, however there are a couple of new wizards mentioned on the Wiki page, that came out with release 2.2.2. I first ran the latency test the old fashioned way, and then the newer way by just typing latency-test into a terminal.

The results:

Old way reports 22,778 nS

New way jitter reports 20,020 nS

I decided that I would take an average 20,544 nS and round down to 21 uS

Now to figure out thread pitch, using the method described here I came up with:

X Pitch Count=5 Pitch=.200 in.

Y Pitch Count=5 Pitch=.200 in.

Z Pitch Count=8 Pitch=.125 in.

My motors are 1.8 degree per step 200 steps per revolution.

From the best  manual I could find, my stepper controller requires 15 uS step hold time, there is no timing information for the direction pin. So, rather then configure step time, step space, direction hold, direction setup times individually, I will use 15uS + 21uS = 36uS as the Base Period for now.

The driver I have can only run full step and half step, I am going to assume half step for now as I can not easily access the jumpers in order to verify.

Next I ran the stepconf wizard and set the IO pins for the parallel port and tried to fine tune and measure each axis.  I followed the directions in this PDF as well as this Tutorial.  There was some error with the Z travel distance and I had to run the program again after the initial configuration.  I was able to edit just the sections of the Z axis that I wished with out issue.  Really nice job on the Wizard/Druid thanks to EMC team.

In the end I decided on 2 revolutions per inch on the Z-Axis, had to open up the motor housing, measure with a caliper and then rotate the stepper shaft by hand.  Seems to be scaled right with what I can measure at this point.

I plotted a couple of the examples from the EMC examples directory just try everything and this is what the machine drew, using the pen tool on the Z-axis.

It Moves…

Tuesday, May 20th, 2008

Just a quick post, I am very happy.

This evening I finished tracing out the main signals to the parallel port. Copied the default files from emc sample_configs into my home directory and edited the default pinout hal file to reflect my findings. Changed just a couple of things in the default stepper ini mostly just to reflect filenames, and …

Figured what the heck, lets give it a go. I was a little nervous about trying to run the machine without isolation, and the ground traces don’t line up between the computer and the machine, but hey!!!

It worked!!!

I had to invert the direction pin for the X axis, but that was a simple edit of the pinout file. Sweet! I ran the test gcode, and moved the machine around manually. Its way out of tune, the scale is way off. However, all of that can be fixed. At least it moves, and thats a very big deal indeed!

EMC Documentation list the very nice User Manual as Well as Integrators Manual. The Integrators manual has a section on tuning stepper motors.

Some Notes from a person explaining how they set up there steppers and adjusted for scale. Seems like the variable to change is INPUT_SCALE in the ini file.

EMC Configuration

Sunday, May 18th, 2008

I have decided to use linux EMC as the initial control software.  First I love linux, second this is fantastic software for machine control.  It runs with on top of a real time kernel and has a nice GUI interface called axis.  As I ramp up on GCODE and CAM/CAD software I have been using AXIS to simulate my produced code.  Its all been working very well.  I have a bit of experience with EMC in the past, using it to help some Senior Design Students retrofit an old StarTurn CNC Lathe.  So, for now its an obvious choice for machine control.  I’ll use this post to document some of the install notes and configuration changes.

Using Ubuntu Dapper LTS for now, even though Hardy Heron LTS is recently out.  My machine for control purposes right now is an older 700Mhz Pentium.  Dapper has been running on this machine for over a year, so for now, just installing EMC along side, will reboot into the realtime kernel to control the machine.

First Step:

Used the install script from the EMC website, changed permissions to executable and it ran fine rebooting into 2.6-15 Magma realtime kernel EMC2 works!

Next Step:

Review standard_pinout.hal to see how its configured by default standard_pinout

A little Research

Sunday, May 18th, 2008
  • Proxy Statement This is Document outlining the exchange of the company to Jot Engineering gives interesting details about the number of this type of machine and cost etc…
  • OZO Support Some ex OZO technicians that will repair and work on these machines, they have a history page images of the machines and, sell replacement parts, software.
  • Servo Spindle Motor Driver Chip DataSheet link for the chip that controls the spindle motor drive electronics
  • Anaheim Automation The people that make the stepper Motor Controller Module
  • User Manual Link to a user manual that is very similar to the controller box in the OZO machine not the same one, however email to Anaheim yielded no return on the exact model number of the box thats in the machine, so far this is the best reference for the hookup.
  • Stepper Motor A catalog from EADmotors Eastern Air Devices, list the stepper motor in the machine. model LA23DGK-23 in unipolar configuration (6 leads) (6.00 VDC) (1.76 amps) (3.40 ohms) (8.4 mH) (168 oz-inch) in bipolar configuration (8.50 VDC) (1.25 amps) (6.80 ohms) (33.4 mH) (210 oz-inch)  Not sure right now the motors are in bipolar or unipolar configuration.
  • 4N26 Opto-Isolator the chip I plan on using to isolate the computer parallel port from the machine controller.  Mainly just because I have some.
  • Parallel Port Link to the Hardware Book parallel port pinout page
  • A Chart of the Pin Out of the Ozo Machine as I manage to trace out the existing connections
Pin Parallel Port OZO Machine
1 Ground Ground (Wired to Pin 1 OZO)
2 N.C. Red Unused (Wire runs to near controller N.C)
3 N.C. Purple Unused (Wire runs to near controller N.C)
4 Clock (Z-Axis) Red Clock (Z-Axis) (Wired to Pin 4 OZO
5 Direction (Z-Axis) Purple Direction (Z-Axis) (Wired to Pin 5 OZO
6 Clock (X-Axis) Red Clock (X-Axis) (Wired to Pin 6 OZO
7 Direction (X-Axis) Purple Direction (X-Axis) (Wired to Pin 7 OZO
8 Clock (Y-Axis) Red Clock (Y-Axis) (Wired to Pin 8 OZO
9 Direction (Y-Axis) Purple Direction (Y-Axis) (Wired to Pin 9 OZO
10 Probe Input Probe Input (Wired to Pin 10 OZO)
11 Y Home Switch High Open Low Closed N.C.
12 X Home Switch High Open Low Closed N.C.
13 Z Home Switch High Open Low Closed N.C.
14 N.C. Y Home Switch (Wired to Pin 11 computer)
15 N.C. X Home Switch (Wired to Pin 12 computer)
16 N.C. Z Home Switch (Wired to Pin 13 computer)
17 N.C. N.C.
18 GND N.C.
19 GND N.C.
20 GND N.C.
21 GND N.C.
22 GND N.C.
23 GND N.C.
24 GND N.C.
25 GND N.C.

Lets See Whats inside

Sunday, May 18th, 2008

Just a few shots to document the innards of the machine. Whats really fantastic is that I found a 3rd party stepper motor driver. This should make motor drive interface at least possible to sort out. Really, I was expecting to find some proprietary hardware controlling the stepper motors, this find is a huge bonus. There is some custom hardware for the spindle motor controller, however at least one of the chips gives a great clue as to how the board might be set up. Some images to clarify the insides.

Front view with covers off testing stages:

Front Panel:

Front Panel

Close up of one of the stages drive mechanism

Stepper Motor

Controller Aneheim Automation

Spindle Motor Controller Chip

Main Board

Note Sheet

–Begin CNC Rebuild–

Sunday, May 18th, 2008

First Steps:

Built Metal and Wood Platform with Castors to support the machine

Cleared a Path to the machine in the Tin Shed

Friends gathered to help move the machine (very exciting)

Open machine to see whats inside…

Similar Machine Model 18