CNC controller problem

Edited By tractionengine42 on 21/04/2017 20:13:58

The symptoms sound like a software problem to me. The usual Windows advice is to "update the device drivers"; updated drivers can probably be downloaded from whoever developed the controller.

Updating won't do any harm.

Sometimes Microsoft is clever enough to detect and install a new driver (Control Panel). Other times the application has some way of doing it. Is there a manual?

On the other hand, a power glitch may be crashing the controller.  Filtering as you suggest might help.  You can also get isolating USB couplers.  It's also worth trying another USB port or interposing a powered USB hub.  This is because not all USB sockets are equal when it comes to power output.

Dave

Edited By SillyOldDuffer on 21/04/2017 20:51:26

Edited By SillyOldDuffer on 21/04/2017 20:52:00

Hi Dave,

I am doing a similar thing at the moment converting an old Conect milling machine to Mach3 with a UC300. Driving the DC motor controller with a 0-10V supply I also found that the USB port drivng the UC300 stopped working until a reboot. Since driving the motor controller by PWM via an optocoupler that problem seems to have gone away. You could try moving the jumper on the UC300 board and using an external 5V supply to improve immunity.

Andrew

The Conect relay contacts had a 0.1uF 120Ohm snubber across them to reduce arcing - similar to this

**LINK**

Whilst I can't say what the problem is. I can say that I have been running a Denford Easiturn with Mach 3, Windows 7 and a UC300. So far I have had this happen two or three times and it has not been an issue. when it has happened I have felt it was software related but this is intuition more than fact.

Regards.

David.

Thanks Gents for your thoughts and ideas, I have very little electrical knowledge so suggestions are a great help.

The problem occurs only and precisely when I stop and start the motor which at present I am doing manually, not via Mach 3.

OK, as a first attempt to solve the problem I will use a separate independent power supply to the UC300 controller. I also like the idea of adding a snubber across the relay contacts. (I did wonder if it would be worth changing the stop/start relay for a solid state device, this could be a bit of a challenge for me though).

I like the idea of including a USB opto isolator, but as these seem quite expensive I will try the above first. As it will do no harm and is of low cost I will also add an EMI filter to the motor controller supply and use a shielded USB cable.

BTW, I have a separate high speed head using a different motor and motor controller. I've just been trying this one out and so far have had no issues. So that's encouraging.

Much appreciated, I will let you know how I get on.

Cheers, Nigel

Edit - BTW the drivers for the UC300 are up to date.

Edited By tractionengine42 on 21/04/2017 22:53:18

I should have said that my lathe has been up and running for a couple of years, though I don't use it that much but the combination has been very reliable.

Does the motor controller have any kind of acceleration / soft start facility and how close is it to the UC300?

David.

I do not switch the motors on my vacuum cleaner or compressor on or off when I am running a CNC program because it always causes the CNC to freeze. This is an electrical noise problem. I think you need to move all of your motor wiring including its supply point as far away from the rest of the system as possible. I start and stop the mill motor manually but it is a vfd driven 3 phase. The switch for this is only a low voltage system and the motor runs up and down under electronic control without current surging in the wiring.

Is you motor wiring shielded? Is the motor power supply going through a spike suppression filter? These may help.

Martin C

https://uk.rs-online.com/mobile/p/products/2192785/

This is the type of power suppressor I am thinking of. 

Edited By Martin Connelly on 22/04/2017 08:16:54

Hi

Thanks again for your help and suggestions.

David - I have the standard (low speed) head and a high speed head, both ramp up and down on stop and start.

Martin - My control system is close to the motor so this may not have been a good idea. The photo below shows the set up for both low and high speed spindles. The cable to the high speed motor is shielded but not to the low speed motor.

​

I have ordered suppression filters and shielded USB cable.

Originally I ran the high speed motor a few times off the machine away from the control box with no problems but that seems to have been luck.

The current situation is that the UC300 almost always disconnects when either the high speed head or low speed head starts otherwise it will disconnect when the motor stops.

I tried starting the UC300 and Mach 3 with the motors already running, the system ran g code for a short while then the UC300 disconnected. On a couple of occasions the UC300 disconnected with the system running idle (no motors or gcode running).

I removed the UC300 from the control box and placed it 4 feet away from the motors (which meant running a long DB25 cable (shielded) between the UC300 and breakout board in the control box. The results were exactly the same, the UC300 disconnected when the motors start and/or stop. This being the case I'm not sure moving the whole control unit away from the mill will help.

As Said I am waiting for some suppression filters and shielded USB cables to arrive. Adding a powered USB hub has been suggested to remove any possible USB power supply problems.

I think I could spend my hours and GBP chasing my tail, I'm wondering if I should ditch the (expensive) UC300 and just use the computer printer port (I did this before when converting a Sherline mill to CNC and rarely had any problems). The other option is to go with the dedicated cnc controllers now available where no marrying of computers, software and controllers is necessary, I do like Mach 3 though.

Again any thoughts or suggestions appreciated.

Cheers, Nigel

Hi

The electrical noise problem appears to be solved!

I had been running everything from the same socket via a multi point extension cable. After plugging the motor controller into a separate socket (still on the ring same ring main) everything is working fine. just spend an hour doing engraving with the high speed head and no problems at all.

So today is a good day and very happy with my new CNC mill build, fingers crossed trouble free running continues.

I will still make improvements by adding suppression filters etc. to be on the safe side.

So the lesson is don't run VFD's etc from the same electrical socket as sensitive electronic equipment. Allot of lessons learnt here about electrical noise and suppression.

Thanks again for your thoughts and suggestions.

Cheers, Nigel

I had a lot of problems with noise affecting Mach3 while running a Dell PC and a Chinese gantry engraver/router. I partially cured it by moving the VFD behind lumps of iron, and putting a galvanized sheet in front of the PC, but during wind up & down sometimes noise still affected the PC.

Eventually the workshop conditions killed the PC and I went to another, with a proper metal case. No interference at all. When I looked inside the Dell it just had a thin metal spray on the inside of a plastic case, which was inadequate shielding. Lesson learnt for me.

Regards,

Richard

The instructions for many VFDs state that they are designed to be installed inside a screened control cabinet.

Whilst some VFDs incorporate filters to reduce injection of noise into the mains, some don't (and the instructions don't always make it clear if there is a built in filter or not).

Correct earthing/screening arrangements can also help significantly with reducing noise injection to the mains (and radiated noise).

By the very way they work, VFDs can produce a lot of noise - it is worth putting some effort in to following good installation practices for both the VFD/motor and any signal or communications wiring.

Hi All

I have a Bridgeport mill running on Anilam CNC controller, My y axes jumps when moving in Y+ but not in Y-, so first I would like to ask if anybody has had this problem, and how can I stop it.

The next problem is more serious the Y moves on it's own always in the Y+ direction, this can happen in the middle of a job, and when it has done it the servo motors switches off, (this is normal), however when I switch the servo back on it moves again always in the Y+ direction.

Can anybody tell me what is wrong & how do I fix it.

I look forward to hearing from somebody, but please no guessing .

Regards Mike

Blimey, you don't want much, just a correct answer from inadequate information. Count me out, as a professional I'd only be guessing.

Andrew

Given the number of good running systems out there, including mine, I have to say that the thought that it must be the software provided a really good laugh,

Thanks! :D

It's the same on the Mach3 forum, everyone thinks there's a fault with Mach3, perish the thought that it might be their hardware