1st time setting up.. whats normal..

[Marlin]

Thank you for the link, I think I understand this and I shall be able to apply this a little further down the line. For now I just need to know what works (or doesn't) with the Kit I have.

On the Roadrunner GCode there is only XY&Z DRO.. No 4th motor! I could just un-enable No. 4 perhaps?

It was always my intention to slave 2 motors for the Y axis and as much as I have seen references to it I can't find any definitive instructions on how it is done.. Any links?

Re: my final question, that was my thought that the stuff supplied was just a suggestion rather than being specific.. I do feel my problems lie in this area.. understanding the PP Pins and their route..

I have not heard back from Longs yet.. we shall see..
Thanks again.

[EddyCurrent]

You can just trace the wires out as shown in the first video

[Marlin]

Just spent a few minutes watching the Video's, I hadn't seen these before. Thank you.
The 1st doesn't so much apply to me at this stage as I have the combined board but will be useful if (when) I get separate drivers and a BOB. The second video was very helpful and have followed along and all my Drives (apart from my dead Y..) seem to do what they should.. so I feel the Pin No.s I have are correct.. yay

Thanks Neale for your comments about the heat, I have now taken to spitting on the motors to keep them cool.. Do I need to spit on the PSU too..? Bzzzt
I am taking this to mean that whilst a program is running and a particular motor may be stationary it is not idle.. ie.. it is powered to maintain that position and will be making some sort of noise rather like revving a car engine in a gear on a hill to maintain ... blah.. Like, riding the clutch..! (I'll get there eventually..)
Does 'Tuning the Motor' seems to help with this heat problem though..?

At the end of the 2nd Video a tantalising reference to slaving Motors.. But.. (I thought it would be quite a common practice.)
I am assuming that the slaving has to happen in Mach3 prior to the driver boards so the same signal is going out to 2 drivers but the actual Motors have 2 wires reversed (on one motor) to allow mirror action..? Sounds straightforward..
Thanks again

[Clive S]

Re the heating on the motors have you set the drivers to the correct motor current setting? With the first 3 dip switch settings .. Clive

[JAZZCNC]

I found in life paying more for something doesn't necessarily get you something better. Hence, the learning curve. Anyhow, I am sure I have read posts with you chastising someone for spending too much and wasting money..

Let me assure you when it comes to drives and motors it really does make a difference paying more for good stuff.! . . . . This is why Eddy doesn't have heating motors or issues.!
I'm not having a go at you and I class telling you this as helping because the way your going the outcome will be you blow the drives which is wasted money and the motors are just rubbish.

Now most of your problems come from the motors and the fact they are are 6 wire motors with high inductance connected to poor drives.

First you have them wired Full winding which is effectively like using Series winding and this means you should run them at half the motor rated current. Your motors are rated 1A but your giving them nearly twice what they would want wired in series and thats why they are getting hot.
Because of the way steppers work they draw most current when at rest so again they are getting hot because your providing too much current. Decent ddrive do indeed drop current to lower amount when at rest. Yours probably don't.
Next the 14mH inductance means you need high voltage to any kind of performance out of them, 24V just is now where near enough to be of any use so between too much current and not enough volts you have shitty running motors with poor performance at best.

To help your over heating problem then wire the motors half winding. So use Black & Yel and Red & White cap the others. This would be like wiring in parallel and use the full amp rating of the motor.

The Road runner G-code is done in imperial units so if your using metric units then the moves will be tiny and can appear like judders. If the G-code says 1 it would mean 1 inch but your in mm so 1=1mm hence the small size and tiny juddery moves. If you scale the axis by 25.4 you'll see a difference in the motors. (Remember to reset the scale factor)

Slaving is completely done in the software and you DONT wire the motors in mirror wire them all the same.
If you have motor going wrong way then you can just change the active high/low pin state in motor outputs.

[Marlin]

Hi Jazz,
Thank you for your response, (I have been a bit un-well for the last few days so apologise for not responding.)
Taking my highlighted comment, I wasn't having a go.. it was more about understanding more about the motors so when it is time to purchase more suitable ones I have more knowledge.
eg : I could pay £5 for my favourite Muller yoghurt's from Waitrose or £2 from ASDA.. Same product. That was my point. VFMoney

With Motor and driver choice, 'Optimum' seems to be the main criteria here, not too big and not too small, but just the right one. There is a natural tendency to go 'bigger' if in doubt it seems..

I will gratefully try and learn from your advice but your 'rubbishing' the hardware just based on price is not helpful. You could equally argue that 'New' hardware is better than 'Old' as progress tends to improve things (not always the case..)

On my bench setup so far, I have 3 motors running and am trying to figure some way of checking the non working 'Y' axis to see if the problem is with my stuff. (Longs are just ignoring my requests for a replacement board..)

As per my heading for this post, I have limited knowledge of what 'normal' is.. which is what I need for my baseline..

(aside) I would love to visit someone's working machine if they would let me (I am near Southend in Essex) as that could answer many questions.. anybody?.. pls.. Will bring BEER.. (No, Yorkshire is too far..)

I have spent much time trying understand what effect having UNI/BI polar, series/parallel actually has.. I have seen the graph of 'speed versus torque' but in this hypothetical state I am currently in, it does not point me in any particular direction..
I feel I have to actually build the beast to then see where my weak points are. I have always learned this way and do not mind spending a bit of cash for my education.

If 'Hot' running Motors are not the norm them I have to assume that Neales motors are not set to their optimum.. I have no idea what 'overheating' means in this scenario.. I accept the motors generate heat whilst working.. Too hot to touch..?

I shall try your 'half winding' suggestion.. I assume I should not damage anything..? What results should I expect? Will it lose torque or rotational speed.. or just lower temperature.?

I tried the roadrunner in Imperial and it didn't like it at all.. It seems to be quite happy in Metric.. But again.. No baseline..

I did find a very useful Youtube video from MachMotion describing slaving (as you say) all done in Mach3 and he wasn't persistently saying 'I am now going to go ahead and....' which seems very popular with out US cousins in their vids..

Would it help if I started a 'Build' log to show my Frame and then perhaps solicit opinions on the best Hardware..? I have done some designs in Sketchup but would rather do a little video viewing the actual build but am unsure as to the best way to post it.. I had tried to put up an Avatar but even my small jpeg was about 5 times too big.. advice please..

[Neale]

A few odd comments...

My motors run hot, depending on how they are being used. For example, a while ago I was cutting some 3D profiles which meant continuous running in the X direction (back and forth) for maybe 6 hours and occasional sideways steps in Y (at the end of each X pass). The Y motor became warm but not hot; the X motor was too hot to touch although it passed the "spit" test. I was a bit worried about this but doing some googling came up with the answer that stepper motors should be able to run like this. Given the capabilities of my machine, I could probably have reduced heating by reducing the current and still had enough torque available, but it didn't seem to be a big deal so I left it, and it did a number of those runs apparently without any harm to anything. Other cuts such as profile cutting out parts where both axes run maybe 50% of the time on average mean that neither motor gets that hot.

As for windings/current/torque, etc, it's all a bit complicated and some of it is not that intuitive, even if you've read the books. I'll try and hand-wave it, to see if that helps. For a given motor, torque is developed proportionally to the current through the winding(s). Double the current, double the torque. Torque also depends on how many turns of the winding the current goes through. Double the turns for a given current, double the torque. In effect, your 6-wire motors have two windings, each having a connection to the ends and one to the middle. For each coil, you could think of it as two windings in series, joined internally and with the common point brought out. So, based on my earlier comments, if you put some fixed current through the whole winding, you will get X amount of torque. Put the same current through half the winding (connect to end point and centre point) you will get X/2 torque. So why would you ever want to do that? The problem is that all the above is talking about "steady state" current, some time after you apply current and things have stabilised. When you first put a voltage across a coil, current will start to flow, but it takes a while to build up. It doesn't start flowing at full value immediately. How slow or fast it builds up depends on the inductance of the winding. Inductance is a bit like inertia - try pushing a trolley with a given force and it will start to accelerate. Put a load on the trolley, increasing its inertia, and the same force will make it accelerate more slowly. You might get up to the same speed, but it takes longer. Same with a stepper motor winding and its inductance. You are sending a series of pulses to the motor, and on each pulse you want the motor to turn to the next step. Low inductance coil/winding - current and therefore torque builds up quickly, motor moves to next step quickly. High inductance winding - current and therefore torque build up slowly and motor takes longer to respond. Put a load on the motor, and the low inductance version will be able to run faster as it builds up the torque on each current pulse to move the load more quickly; same load with a high-inductance motor and if you don't give it enough time on each pulse of current to build up enough torque to turn the load, it's going to sometimes fail to turn (missing steps) or in an extreme case, sit there vibrating a bit and not turning at all. That's why the recommendation is to use low-inductance motors. With a 6-wire motor, the best compromise is probably to use half the winding, which means only half the maximum torque, but also halving the inductance so you can keep up the stepping rate. With an 8-wire motor, you can choose to put each pair of windings in series (high inductance so limiting speed) or in parallel - low inductance so higher speeds, but you will need double the current capability from the power supply and driver as you will be putting the same current through each winding. The other way to get speed up is to increase the power supply voltage. Double the supply voltage and (roughly) you double the rate of rise of current. So you get to the final value more quickly on each pulse, so reach the torque needed to move the motor more quickly, so can run faster. If you read the data sheets, you might well see that a motor is rated at a nominal 4V but in a practical system, the power supply driving that motor will be at 65V. That is purely to make sure that the current rise is fast enough to develop max torque. The driver sorts out current limiting and so on to make sure that the motor is not overloaded - that's what the current setting on the DIP switches does, and you would typically set this to around the max motor current rating and ignore voltages. So the typical cheap drivers with their 24V supply will not allow you to run a motor as fast as you could with 48V or 70V. However, the higher voltage drivers and power supplies cost more.
As I say, that's all a bit hand-waving and there's plenty of theory that I've skipped or simplified, but having that kind of picture might help put some of the advice you've been given into context. It's all built on a sound technical background! Higher speeds come from low inductance motors driven by high voltages and drivers to suit; cheap kits have high inductance motors, low voltage supplies, and sometimes rather flaky drivers built down to a price. Tends to lead to disappointment all round!

[Marlin]

Thank you Neale, I actually understood quite a lot of what you say even on 1st reading but I will refer back to it as my knowledge hopefully grows and it will make more sense.
I don't think I will ever truly understand electronics, I would love to but I just don't think my brain is wired that way.
I particularly like your use of Analogies (induction) and would ask you to try and assist me with one..
Here goes..

I am in a Car driving up an endless flight of stairs, step by step..
I (my brain) is Mach3 sending information to my hands and feet (Gcode).
The Engine (Stepper motor) is on and I am in 1st gear (Manual gearbox) and my front wheels are sitting on a step while the rear wheels are in-between steps sitting on the nosing of a tread. I am 'riding' the clutch to stop me rolling backwards.. ie the stepper is using ('Gas') electricity to hold it's position..
I wish to move up the steps so I need to send information to my accelerator foot to give just enough Gas (pulse) to move the front wheels up to the next step.. (a line of gcode..) and, Stop.

The variables are many.. Do I have a large Car with a very small engine.. or a Veyron FU..
How good is my clutch.. How good is my clutch footwork..
What fuel am I using, Diesel will generally give better torque than petrol.
Do I have an Old Car that has Carburettors or a newer one with Injection and engine management systems..

I am trying to equate this analogy with the path through from Mach3 to Motor..
So..
1st problem to me is making sure all the separate components actually work.. and then, are they compatible with each other..
Assuming they all are & do, then joining all the wires to their correct home seems well documented and reasonably straightforward.
Configuring the system I think comes next..?
If continuing with the Car analogy then this system seems to relate back to Model T Ford era where each element has to be set in the correct order, Ignition on, fuel pumped, magneto magnetoed (no idea..) apply Choke (and I'm sure, lots of other jobs) prior to starting the Motor.. Then, as you trundle off, modifying things as you go..
(Rather than modern Cars with their 'Key In and Go' simplicity.)
I feel this is similar to the complex 'setting up' process with CNC Machine Building. Is this reasonable?

I have run out of Analogies but perhaps you could offer (or direct me to) your particular story of how you chose what you did and why and how you the put all the pieces together.

I am concerned that many of the Build Logs are quite old now and I don't know if new products/knowledge have superseded them..
Also..
Are there some critical measurements that can be proffered by newbies like myself.. Like, Table size, weight of Gantry or ? to assist the Elders in guiding us to relevant information..

Thanks again Neale for your help.

[JAZZCNC]

eg : I could pay £5 for my favourite Muller yoghurt's from Waitrose or £2 from ASDA.. Same product. That was my point. VFMoney

With Motor and driver choice, 'Optimum' seems to be the main criteria here, not too big and not too small, but just the right one. There is a natural tendency to go 'bigger' if in doubt it seems..

I will gratefully try and learn from your advice but your 'rubbishing' the hardware just based on price is not helpful. You could equally argue that 'New' hardware is better than 'Old' as progress tends to improve things (not always the case..)

Ok first let me say NO where did I rubbish based on cost.!! . . . I rubbished based on fact and experience that these TB based drives are RUBBISH and Hi inductance motors give poor performance.! . . . If that's not what you want to hear then that's your problem it's still a fact.!

Also they are not value for money when the don't perform as desired or has often the case they let the magic smoke out.!

The fact no one is telling you what to buy is mostly because they can't accurately recommend anything without knowing more about the build.! . . . It would be wrong to give explicit recommendations without knowing more details.

What can be given is ball park setup that is generic to most machines of the size your suggesting. For some it will be OTT for others spot on but in all cases it will give great performance and reliabilty. . . This will be value for money.!!

What it won't be is very cheap as the simple fact of matter is to do this correctly so you get correct level of performance along with reliabilty requires a certain amount of investment.
This is what I've been saying regards you wasting money because what you have bought will be woe fully slow and under powered due to components being completely unsuited to each other and also configured in the worst way.

Hi inductance motors require higher volts compared to low inductance motors to push the current thru there windings and when wired in series like you have they require much more than 24v to get anything like decent performance. The drives won't allow more volts other wise magic smoke appears so your stuffed with this setup.! . . . . . Completely NOT value for money.!

Now your comment about "tendency to go "bigger" " is correct but also wrong at same time. This common tendency to go bigger is often done with nema 34 motors and fatal to performance for similair reason's. Mostly lack of voltage/cuurent and therefore speed/torque.

You only have to look around the forum to see the COMMON setup that works. This is not "Drive" or "Motor" snobbery or sheep following sheep it's simple fact that it this setup works for a wide variety of machine setups.

The setup is as follows. Now whether you pay the little extra and get the digital drives is a choice you may decide based on your wallet. Personally I will only use digital drives because of the advantages they give over analog drives. They are smoother, run motors cooler and in some cases give more setup options which can be life savers if resonance plagues you.!
One other thing is that often digital drives are better protected against wiring wrong or loose connections falling out which would other wise kill lesser drives (I know of several on this forum who have had there arse's and wallets saved by these features.!!) . . . . But analog drives still work good if correctly matched so it is choice based on cost that doens't have a massive affect on performance.

8 wire 3Nm 4.2A nema 23 motors wired in parallel. (inductance around 3mH when wired parallel)
2 common setups for drives upto 50Vdc or upto 80Vdc (80Vdc prefered for safety margins)
PSU 44Vdc upto 50Vdc drives: 68Vdc for 80Vdc drives.

The higher voltage setup is better not just for performance but also there's a larger safety margin drives and back EMF while still getting great performance.

One last thing regards belt drive. It often ends up costing the same or not much less has buying ballscrews from china by the time you have bought pulleys etc so check it out.

[EddyCurrent]

The 1st doesn't so much apply to me at this stage as I have the combined board but will be useful if (when) I get separate drivers and a BOB.

It does apply because it shows how the pin numbers were derived, about 5 minutes into the video. I'm not convinced you have the pin numbers right in Mach3.