I vote "yes".
I don't know if there is already an open source Mach3 turn on/off and speed controller interface for a Sieg X1 or X2 type spindle drive (for the original DC motor) keeping the original Sieg drive and the manual speed control option.
Some time ago I started working on a converted Sieg X1 and made one interface for my own use. Since my free time was very limited at that time, I made it on a protoboard on the fly and have no schematics. Parts used were the ones available at my home shop and I don't think I used more than $20 on parts.
Now I have a little more time and would like to document the interface, design, send gerbers to a fab and assemble a proper PCB for it.
The circuit uses 3 small relays. 1 opto coupler, a few transistors, a couple of small signal mosfets and one IC (it uses the charge pump signal from a K4 board, otherwise it would need to duplicate the charge pump detection circuit using another IC). Spindle controller is completely isolated from the PC. Just disconnecting the interface cable or pushing EMG stop in Mach3 restores manual operation if required.
Forward/Reverse is still manual I don't think it is difficult or too expensive to add but I didn't need it. You can also manually turn off the interface and no remote control is possible (for safety). Note: My interface does not replace the original Sieg motor drive. It keeps the original "potentiometer' switch behavior" functioning because I consider it a safety mechanism.
Before dedicating more time to this thread, Is there any interest on this subject?
Last edited by kreutz; 04-09-2012 at 03:07 PM.
Anyways, I am planning to do it for my own X1 CNC converted so at least you will receive a copy of the documentation if you want it.
The complete schematics, PCB gerbers, assembly and setup instructions, etc. won't be available right away, I need to dedicate some time to re-design them and after my new board is populated and working I will post everything. I would like to include also a feature that is not in my original board; as a safety feature any error condition on the spindle drive should trigger an emergency stop so the whole system stops. I haven't had any issues yet but it seems like the correct way, it is very easy to overload the spindle drive.
I've been dragging my feet on converting my X2, so while I'm interested in seeing your work, I'm certainly in no rush.
Whenever you do get to the point of publishing your work, if you want a volunteer to do some testing on the X2, I will probably be able to help.
More information about my original speed controller implementation.
As I wrote before, my original design was done on the fly (no schematics) and the parts were soldered on a Radio-Shack's proto-board. No pictures will be available because the wiring was really a mess and the board was wrapped in xray film as insulation, it was really intended to be a proof of concept but it survived for three years.
The board contained a microcontroller (Atmel ATtiny2313-20PU), a 10 pin connector a few 2N2904 transistors and some 2N7002 mosfets, a 20 MHz xtal, optocoupler, some resistors and capacitors. Attached to the board were a couple of 24 volts dc DPDT relays (my controller box uses 24Vdc for the power relays and safety circuit) and a 40 Amps Solid State Relay (I know it was an overkill) for powering up the spindle.
The pwm signal, M3/M4 and EMG stop signals came from the K4 PC interface board's external interface connector and were RF isolated from the PC.
One of the 24 vdc relays was dedicated to emulate the potentiometer switch, the second set of contacts were used to discharge the PWM integrating capacitor that produces the 0 to 12 Volts signal to emulate the potentiometer.
For the new design I will keep most of the original components but the user will decide which relays to use, so they won't be mounted on the PCB, there is also no need to use a big (and expensive) SSR for the spindle power control.
I was browsing the web and came into the following options for the relays so you won't have to use the same model as the ones I found around my shop:
RLY-453 120Vac DPDT 12Amps@250Vac contacts 1/2HP.............$1.75 each
SRLY-19 1 Amp SSR 3-8 vdc input, 120Vac output @ 1 Amp.........$3.25 each
(could used to drive the above mentioned 120Vac relay)
RLY-497 12Vdc DPDT relay, 5A contacts @250Vac.....................$2.50 each
The above mentioned part-numbers are from All-Electronics and I don't have any relationship with that company.
The second 28 Vdc relay I used was the one controlling the Mach3/Manual drive mode on the original design.
The microcontroller's function was to simply emulate manual mode at power up and power down.
On the new design the microcontroller (which could be a different chip) gets new roles:
1. Trigger EMg stop when the spindle drive is overloaded and shutdown the spindle power.
2. Optional RPM meter (triggered by inductive or opto sensor) with 7 segments LED display.
There will be no need for the K4 interface and you could use whatever B.O.B. with isolation. The original speed potentiometer/switch will probably be re-assigned and taken away from the original drive and interfaced to the micro-controller in order to use only two relays and eliminate the third one. Manual control will still be available but the interface board will provide the pwm signal instead of Mach3. This modification will make wiring more simple.
Last edited by kreutz; 04-11-2012 at 01:31 AM.
It certainly sounds straightforward enough...
I'm not sure what a K4 interface is, but I do have a BOB with some spare outputs that I can use. I have no atmel experience, but could probably substitute a PIC. The rest of the parts (other than perhaps the SSR) I might have in my junkbox (but All Electronics is a pretty good source for parts in case I don't have a suitable relay or two).
New design will keep a few things from my old (prototype) board but relays and SSR will be off-board, so everyone will have freedom to choose whatever is available (or cheap) for them. I will include (on the board) a couple of 2N7002 mosfets to drive the dc relays or SSRs. The original potentiometer (with attached switch) will be attached to the interface board, so you can keep manual speed selection but the interface board will be still simulating the original potentiometer. The Attiny2313 micro-controller will stay (why?, just because I have a lot of them... ).
The way it is going to work is as follows: As soon as you turn on the switch on the manual potentiometer the controller is going into manual mode providing the X1 or X2 controller the 0 to 12Vdc voltage to set the desired speed (as the original potentiometer did). The controller simulates the potentiometer switch actuation using a pair of relay contacts. The potentiometer now won't have any lethal voltages (will work from 0 to 2 vdc) supplied by a low voltage (5V), low current, power supply provided by the user.
When the potentiometer's switch is in the off state (closed) the system is in CNC mode and receives step/direction signals (or PWM + M3/M4 signal + charge pump as enable) from Mach3 /parallel port/ B.O.B. of your choice. When the command cable is disconnected the system will work only on manual mode, so it will be immune to noise from the connector/cable when not connected (there will be a safety interlock jumper on the B.O.B. side of the cable).
Last edited by kreutz; 04-27-2012 at 12:42 AM.
The interface board will (probably) be compatible with the mini lathe. I don't have any mini-lathe spindle controller's schematics available to be 100% sure now.
I have a mini lathe also, but not sure that I have seen a schematic of the spindle power board.
There used to be someone in the UK who repaired spindle power boards for mini mills and lathes, and he might have had schematics on his site at one time, but I don't think he is in that business any more, and I don't know whether or not I once downloaded such a thing from that site - I could be mistaken.