Losing steps/position, again

[JAZZCNC]

Maybe worth taking a video because missed steps don't really knock.? A knocking would certainly make me think mechanical.

[ngwagwa]

This is the knocking noise https://lozharroplures.co.uk/my_images/Xaxis.m4a

[JAZZCNC]

This is the knocking noise https://lozharroplures.co.uk/my_images/Xaxis.m4a

That's not missed steps. It could be something electrical or computer related with parallel port causing problems with the pulses, possibly? However, the first place I'd start is with Motor and pulley couplings, belts etc and checking out the mechanicals.

[Kitwn]

The fault is now present all the time except every now and then after turning everything on I can sometime jog smoothly for a few minutes before it shows.

Is anything getting hotter than it used to? Have you dusted the PC processor heatsink and fan lately?

[ngwagwa]

Well, having just been browsing I was looking at Ethernet (as it is one thing I understand)

My spindle is controlled via a serial port and a plug-in so that is one thing I don't need to worry about.

Saving up is not an option as having the router misbehave is costing me money, so having just spoken to my pension provider it is time to start planning.

By my reckoning I need:
1) an Ethernet based motion controller
2) a connection block and cable to the controller
3) PSU
4) 3 drivers

Mount all these on a board, (now it gets tricky) connect the outputs from the current drivers and the limit switches/probe switch to '#2. Rip out everything from the control box and install the new setup.

[ngwagwa]

I have just had my head in the control box and I can't see anything that may be the drivers for X,Y and Z. It looks like the guy that converted it to mach3 thought the easiest way was to hang an old plastic kitchen chopping board to mount the new BOB on right in front of the original control board.I will just have to wing it and make sure I find the stepper motor leads when I remove the existing circuitry.

After spending last night looking at possible options I am drawn to an AXBB-E Ethernet motion controller and breakout board combined controller as includes a BOB plus it is in stock at https://www.stoneycnc.com/axbb-e-eth...r/a4753?c=3479.

Can you suggest suitable drivers and PSU?

[dazp1976]

If I did it again I would get drivers that are rated upto 80Vac/110vdc and use a 70Vac toroidal transformer.
Something like a 2*35vac secondary outputs wired in series for 70vac.
Doesn't matter wether you have Nema 17/ 23/ 34size motors etc, the drivers regulate output voltage to the motors themselves.

For the bb-e it needs 5v and 24v. Could use either voltage stepdowns from the toroidal or seperate switched psu's. Depending on how many relays you have will determine what amp rating they will ideally need to be.

[JAZZCNC]

If I did it again I would get drivers that are rated upto 80Vac/110vdc and use a 70Vac toroidal transformer.
Something like a 2*35vac secondary outputs wired in series for 70vac.
Doesn't matter wether you have Nema 17/ 23/ 34size motors etc, the drivers regulate output voltage to the motors themselves.

That's WRONG information your giving out, the drives don't regulate the voltage they regulate the current. 70Vac which is 98Vdc would destroy those little motors in no time at all. It would also make them run like a bag of shite.

You cannot stick any voltage you like into a stepper, there is a limit where it starts to have very negative affects. Namely iron losses and motor heating which kills them.

Those Large voltage Ac drives are only really any good for larger steppers Like Nema 34 or very high inductance NEMA 23's. Your typical 3-4Nm 4.2a Nema 23 with 3-4mh inductance doesn't like to be run much more than 80vdc and at that, you are pushing them past there design threshold so are shortening there life.

For the NEMA 23 motors, which this machine will have fitted he'll only need drives with a max rating of 70Vdc and would run them around 55-60Vdc. Or 50Vac drives running at 40-45Vac.

[ngwagwa]

That's WRONG information .......

Thanks - obviously reducing the power I supply will also reduce the initial outlay (as well as havingto replace everything including burnt oout motors).

Could you be so kind as to point me in the right direction for what you would suggest and is there ay advantage with a toroidal transformer (a plug and play box suits me if possible).

Although I have asked elsewhere on this forum have you any reasons why I shouldn't use the AXBB-E motion controller?

[JAZZCNC]

Thanks - obviously reducing the power I supply will also reduce the initial outlay (as well as havingto replace everything including burnt oout motors).

Think I've just answered this one in last post but sorry you need larger not smaller for the reason stated below.

Could you be so kind as to point me in the right direction for what you would suggest and is there ay advantage with a toroidal transformer (a plug and play box suits me if possible).

Ok well the advantage with toroidal transformer, when used with capacitors and bridge rectifiers that make up a DC PSU, (yes you need these as well) is that it means you can get away with lower power rating than you would need with a switch-mode supply. You can also build to the exact power requirements you need.

It gets complicated but in a nutshell, let us say you have 4 motors all pulling 4a which means you'd need a 16a for a SWM supply to work reliably and keep up with drives/motors demands when working hard. In practice, the actual rating needed will be higher for reasons I won't get into now. But all this means a Large SWM PSU this size gets expensive quickly.

Whereas a Toroidal/capacitor-based PSU allows you to get away with PSU size only 60% of the motors total draw. It does this by drawing from its bank of capacitors and how the drives work. It also ensures a smoother flow of power because you always have a reserve in the capacitors.
So again, in a Nutshell, yes it's best for these reasons and the fact can size to exact needs and it's often much Cheaper when higher power is needed which is why it's used so much on routers and DIY builds.


Regards the AXBB-E Controller I have never used one personally so I'm not recommending you use it but I do know several people who have used them and are very happy with them. I've fitted several of its Big brother the Uc300ETH and they are also very good so I cannot see these being a bad card. The UCCNC software is also very good so I wouldn't hesitate if it was me.