View Full Version : Techsoft "CamCut 300" cnc machine...

06-16-2005, 05:39 PM
Hi, I just managed to get this machine off my school (after 3 years of nagging) for the mild price of £30...

I will take some pics later, it is half in bits already as it doesnt work..

anyway, it was made in 1994 by "Multisoft Robotique" and "badged" (although no badging physically) by techsoft. It is built like a tank (or at least very sturdily) and after a little probing i came to the following info.

It ran from an acorn, of which i have the software, and acorn (from the school) all the books and stuff, even 3 collets..

It runs via serial

it has 3 "Step-syn" 3v 2A 1.8DEG/STEP motors in it and a router for the main spindle (yet to work out if thats mains, but i am 95% sure it is, even though you could alter the speed in software.

My tech teacher said it worked fine for about 3 years after they bought it, then it just stopped in the middle of a project, and never worked again. Techsoft said they stopped doing them 2 years before that and unless you spoke french, multisoft were unhelpful too. Anyway, that was now 6 years ago...

It blows 2 fuses when plugged in, so i am not sure whats up there.. my view is that uness i get the acorn system set up, software on it and it works (which it wont...) also because the acorn wasnt the origional one it worked with, its an A3000 it doesnt have a serial port

A few questions though:
the motors have 8 wires, they tied them in pairs, makeing only 4 wires, what type of stepper motor are these, i assume bipolar, is that good?
EDIT: they are "Step-Syn" made by "Sanyo Denki" type 103G770-2249 motors.

wire colours are:

Black, Brown White, Orange Blue, Red Grey, Yellow

What is the best driver board for these motors would you reccomend to drive this in the classic way?

i will post some pics later!


06-17-2005, 07:55 AM
I have made an interesting discovery...

I have stripped the thing down now, and have been prodding around, however, 3 things interested me most:

1) it has only 1 limit switch per axis, which i cant work out, how does it home when it has only one switch? I assume the switch is there as a home switch only and not limit, but i am not sure, what happens if it winds to far in the end without a limit switch?

2) the old logic board (HERE (http://hellzbellz.net/screen_dumps/CNCMILL/DSCF0001.JPG) (300kb)) features 3x "Easy Power GS-D200S" modules. (aswell as a multitude of other stuff) after 3 mins of resurch, it turns out that these are fully featured by polar drivers in themselves, accepting a Step and DIR input!! They are basically geckos! assuming they arnt dead, this will be easy! As far as i can tell, most of the othe board is for buffering / spooling data over the serial port and controlling the speed of thespol motor!

3) what is the easyest way to test bipolar motors? these ones have 8 wires (i assume 2 per phase) so i wouldent of thought it would be that bad...

Also, since the motors are 3V, could i use a PC powersupply for this? (3.3V at about 20A! and 5v for the logic! i know it would be like 10% over but surely that wouldent matter too much..

EDIT: Datasheet (http://www.st.com/stonline/products/literature/ds/2666/GS-D200.htm) for the Easy Power modules

am i missing something or can i just connect step and DIR lines to parallel port via a breakout board?

06-17-2005, 08:17 AM
Hi there,

I'm no expert on this stuff, but I can tell you that I'm going to run my 4.5V 2.5A stepper motors off a 35V supply (yes, a LOT higher than the motors' ratings).

I am using a Xylotex unipolar board and as far as I know, the reason why this can be done is because it is a 'chopper' drive. As I said, I don't know an awful lot about this stuff (and nothing about your drivers in particular...), so don't just plug your board into a big supply (and then blame me if it goes up in smoke:D ) - rather wait for a more experienced 'electronics' guy to help you out.

Sounds like you got quite a lot for £30 though...


06-17-2005, 09:06 AM
to be honest, i have yet to figure out exactly what "Chopper" boards do, i understand the principle between fullstep and halfstep (which these drivers support!) but not chopper. since PC supplies give out 3.3V and 5V couldent i just use that to power this whole thing?

06-17-2005, 09:33 AM

Sadly, I couldn't explain how a chopper drive works, but I do know that it allows you to run much higher voltages through your motors than they are rated at.

I had a quick look at the datasheet for those drivers. It looks like they are chopper drives. It also mentioned something about the supply voltage being between 12 and 42V. I'm not sure if that means that lower voltages than 12V won't work??? I was also advised to run a higher voltage as the performance increase is quite significant - mainly in speed I think.


06-17-2005, 09:49 AM
yes, i noticed that the input must be between 12-42V, since these were in the machine and the motors in the machine are 3v, it is fair to say that choppin seems to be in play here...

I face a perdicimant -> unsolder the Easy Powers (proably) and make up a new system using the parallel port

Try an get the old board working (probably now as it is serial, porbably uses a weird protocul and the acorn i have has no serial port. and this thing didnt work anyway..

so basically:

Assuming i use a PC PSU for this (i could use the 12V line instead of the 3.3v one then) i can use the PG line to switch the enables on these things so thats ok (i could switch it manually to) and a reset button on the Rset lines etc..
I could join the Sync lines together for the chopper (WHATS A CHOPPER!!!)
leave it in half step mode (is half step better than full step, are there any advantages in having full step?)

Also, whats slow decay and fast decay?


06-17-2005, 11:36 AM
this thing has a torroidal transformer mounteed in the case outputting 24V and the main board has a whipping sized cap (4700uf - 63V) and a large bridge rectifier so i assume that was the origional power for these drives, i might as well reuse it. (if it aint borked)

also, i think i have the limit switch system sorted, the Easy Power modules feature a "Home" and "reset" lines, from what i gather, if you get it where u want home to be, you take Rset low for a sec and whenever the motor is in the same place again (3 bit counter it says) it takes the home output line on it high (so no limit switch needed) to be honest i still dont see how this works...

HERE is a test schematic i am going to use if none of you say something along the lines of "OH GOD WHAT AN IDIOT -- he should do this this and this..."

Before i get underway designing a PCB and circuit utalising my 3 drives and motors, i want to check them (as this thing doesnt work ATM, i want to ensure none of the motors are burnt out etc...)

using the datasheet for the drives, i whipped this really bad pain schematic up (<2 mins)


hopefully the 555 oscillator will be able to make the motos spin and hitting the DIR pin (7) i can change direction. i will monitor the "Home" output with my scope as well as the 555 output. Sync and Osc (2 &8) are left open as i am not using many of these when testing and Ioset is floating to enable 2A output. Control is also left floating to enable Slow Decay (What does this mean)

if anyone can tell me:
1) what chopping is
2) what slow and fast decay is (sound like radioactive measurements!!)
3) if i am doing anything wrong
4) what the input voltage should be... i assume this has something to do with the chopping but i am not sure... chopping is at 17khz BTW.

06-17-2005, 01:26 PM
I will try to answer your questions, but I think that there other people on this board who have more knowledge of the subject.
But allright, here we go.

1) Chopping is a way to limit the current, when you use the search you will find some very detailed explanations :


2) This is my guess, I think it has something to do with the acceleration/deacceleration of the steppers (However radioactivity sounds much cooler ;-)). Or it has something to do with the logic, the rise and fall of the pulses ?

3)As far as I can see you're doing nothing wrong. Not in the livethreatening sence anyway .Only instead of using a 555 I would use Mach2(demo) and wire step and direction and ground to your parallel port. This way it's easier to change things like the frequency of your step pulses or even make little test program with different speeds.

4)I couldn't open the pdf of the driver but I should start with 12V since a higher voltage only will make your stepper run faster and stronger (more torque) at higher speeds. Chopping only affects the current, as far as I know it has nothing to do with your input voltage.

I also read that your steppers have 8 wires, this make them very versatile.
You can wire them uni-polar or bi-polar with 2 windings parallel (more torque) or bi-polar with 2 windings in series (higher max. speed).

BTW I would realy love to see some pictures of the machine.

06-17-2005, 05:27 PM
ITS ALIVE! By following that circuit above i had a motor whizzing the Z axis up n down at different speeds! The motor growled a bit but the VS power (motor power) was only 12V - it was 24 in the machine, so i susspect this accounted for that. One of the easy power modules took me 3/4 of an hour to unsolder, very very hard to do without a proffesional desoldering station. (i only had a manual sucker thing)

Still to work out about Home limit switches, the origional PCB had nothing connected to the EP (easy power) modules home or reset I/O's (which, as far as i can see) work using a counter and give a output when the motor is in a specific location, but weither this is globally (I.E one place on teh axis) or when the motor / phase sequence is at a specific stage is something else i have to test.

anyway, some pics of the machine and the knoledge that atleast one motor / controller works. just 2 more motors and 2 more controllers to test, PCB to design, old PC to aquire, TurboCNC / Mach2 to fiddle with, wiring to be done.... It goes on... :cool:


::300kb each:::

Have abrowse around here (http://www.hellzbellz.net/screen_dumps/CNCMILL/)


06-18-2005, 07:58 AM
may i ask, if i have a torroydal transformer and it says
SEC 25VAC @120VA

that is not 120Amps is it? How many amps would this be?

BTW: got the other 2 drivers out so testing today!

06-18-2005, 08:42 AM

Judging by the units (VA), I would imagine that that is the power rating.

The max current would then be 120/25 = 4.8A


06-18-2005, 11:53 AM
ok, cheers!

got all 3 drivers working fine planning a PCB now...

only issue is that the spindle is a 240V router which spins at 30'000 RPM if directly connected.. in the origional circuit it was triac / SSR controlled (still cant figure out how, it had a BT139 600 M9432 Triac on its feed as well as a S212S01 SSR (Solid State Relay) which appears to be a optoisolater..

any simple meathod of controlling the spindle speed either manually (like a light dimmer) or via PWM on the parallel port?

06-24-2005, 12:31 PM
just finished building my new controller system and 80% of it works

one of the modules takes alot more juice than the others and makes the motor sing.. it also gets hot (as well as making the regulator for 5v logic get hot)

any ideas what i might have done? will post pics etc in a mo...
attached is my PCB layout, it is in 3 parts as i cant do a PCB that big, so i split it and it is joine by 15 amp hard core wire (like in walls) across the gaps to hold it stiff.

everything else on the board works... the SSR seems to conduct a bit even when off, which is weird...

datasheet for drivers:


i would appreciate any help on this... driving me nuts...
the module that makes the motor scream BTW is the "Master" (page 13 of that datasheet) cheers!