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Author Topic: Hello 1st post, need advice on controller, board, drivers  (Read 18925 times)

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Offline jimpinder

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #20 on: April 07, 2008, 10:23:03 AM »
Scott - The clique that is testing the "smooth stepper" is keeping everything close to the chest.

As far as I understand it, all it is is a USB version of the LPT1 printer port.

When Mach3 started, the system to connect the computer to the machine was a printer port cable. This was satisfactory, it had the necessary speed and all computers had one. To be fair, it's cheap and it works well - I am still using mine - because my system is simple.

The big problem with it is the lack of pins (outputs and inputs). There are 8 outputs (mainly to drive the axis - 2 wires per axis), another 4 outputs (mainly for coolant, spindle motor on off and reverse) and 5 inputs. The inputs are a problem. If you want limit switches, home switches, spindle speed reader, and feedback from any measuring device you have on your machine (like servo motors) then there is just not enough input via the LPT1 port.

You could get additional printer ports, but modern computers are now coming out without the old 25 pin printer ports and doing everything via USB.

I understand the "smooth stepper" is just that - a collectionof input and output ports to connect to your machine - and all you do is plug in a USB lead. I understand there is also some sort of driver chip (s) on it, so whereas before your computer generated all the pulses necessary to drive your machine, now the smooth stepper does a lot of the work. This means that the type of computer is less demanding - many of us like laptops in the workshop (but some of these had problems). Smooth stepper will apparently work with any computer that can run USB ( I assume USB 2")

Thats my bit - no doubt I will get shot down in flames if the info is wrong - but as yet I've got to see a spec - come on guys - let us into the secret.

Not me driving the engine - I'm better looking.

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #21 on: April 07, 2008, 11:13:36 AM »
There is info about the SmoothStepper on this forum and also Gregs own forum. 
http://www.machsupport.com/forum/index.php/board,65.0.html   and
http://www.warp9td.com

 Basically the SmoothStepper does away with the need for a computer with a parallel port, it also basically has the pinouts of two parallel ports and also has additional inputs for encoders or MPGs. The normal way of setting up motors and all other I/O will be the same, ie you still use ports and pins and still use the Port column for defining which port they are on.
 The SmoothStepper does the pulsing and as was said this does away for the need of a software pulse engine, leaving Mach to concentrate on the calculations. The pulse rate is at 4MHz max at the moment where the Parasllel Port is 100KHz, thats a 40 fold increase. Also even at 4MHz the pulse is super smooth :)
 I have run the smooth stepper through the Pico motherboard that I am using on my milling machine that I am in the process of retrofitting. This Pico motherboard is tiny (100mm X 72mm), has a 1GHz embedded CPU and up to 1GHz of memory, onboard graphics, LAN, Serial, 4x USB and PS2 for mouse and keyboard. I tried running Machs Driver Test on this board and it wouldnt run, just locked the pico up, however with the smoothStepper it works perfectly, I have not had it running my new mill as its not ready, so I couldnt test at the speeds I will be running the new mill at. However I did have it hooked to my old mill and it ran it perfectly at the feedrate of the 3D programme which was 1000mm/min. see here http://www.youtube.com/watch?v=bApuwkkXTb8
 There is word of addon boards for the smoothStepper that will add to the I/O but not sure what or when.

Hood

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #22 on: April 07, 2008, 11:15:11 AM »
Oh and BTW to let you know how good I think the  SS is, I have ordered 2 for myself in addition to the Beta one I already have :)

Hood

Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #23 on: April 07, 2008, 08:51:14 PM »
I've seen your youtube video and a few others, pretty cool! All sounds great, I can't wait to get it all set up.

Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #24 on: April 15, 2008, 05:29:02 PM »
OK, I found some more info. The motors are DC servos that are fed with 115 volts. They also have a servo amplifier on each servo. I will upload a diagram of the motor and servo combination. I also found a partial diagram of the main wiring from the manufacturer, I believe the L1, L2 ans L3 are the limit switches and it shows the E-stop. I emailed the company that created the retrofit to see if I could get the wiring schematic for the boards and such, they said they could make a set for me for $70.00 that would NOT include the servo amplifiers, they say they are proprietary, I guess that meens they won't give that info out. My questions are, will the smooth stepper work well with the servos I have? Would having the wiring schematics without the amplifiers be sufficient for me to set this up? What is a servo amplifier and what does it do? Do they make the motor work faster?
« Last Edit: April 15, 2008, 05:47:28 PM by NJC »

Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #25 on: April 15, 2008, 05:58:18 PM »
Here is a diagram of the back of my control enclosure, note the listing of the encoders, limit switches, e-stop. Also at the bottom it says the amplifiers are digital and the servos are 280 oz and that is is a closed loop system using the encoders, Does all of this sound like it will be compatible?

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #26 on: April 15, 2008, 06:46:22 PM »
Amplifiers are the Servo drives, its just another name for them.
 The Smooth Stepper is basically just a replacement interface for the parallel port, it uses the USB and allows you to connect all the I/O that you would manage with 2 paralell ports. It also has the advantage of having the pulses preduced on it rather than the software pulse engine. This allows much faster/smoother pulse rates and will allow the use of almost any computer, even those that gave problems in the past like laptops.
 However it will not allow you to use your servo drives if they do not accept step and direction, so if that is the case you will need to either get a Step/Dir to analogue converter for each drive or get new drives or stick with what you have.

Hood

Offline jimpinder

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #27 on: April 16, 2008, 04:15:28 AM »
I think Hood has put the problem simply - I assume the equipment you have got, when it is all put together, will drive your motors - and hence the mill.

Mach3 is NOT a DRIVER - it is a controller - so the question is, when you get it all together - what makes it work - in other words - what signals do you need to put in to make it go backwards and forwards.

It is unlikely that the bits of your system will be all in one. There will be a seperation some where, between the computer that did all the calculations for the system and told it what to do, and then the driver side - which took those signals and converted them into movement.

That is the point on the system you need to find.

Mach3 provides - for each axis - three wires - a "step" wire, a "direction" wire and a "return signal" wire ( the return signal wire might be common to all axis - therefore it might appear as only two wires per axis, plus a common).

On the "dir" wire, Mach 3 puts out a +5v or 0v signal  dependent on the direction the axis is to go, and the "step" wire puts out a +5v pulse (or a 0v pulse - it can be altered) the frequency of which is dependent on the speed of the axis, and the number of pulses drives the axis a set distance (on mine 48,000 pulses = 1 inch or movement)

This is the basic system Mach uses - so unless you can find a place where you can input step and direction pulses, you are a bit stuck.





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Offline jimpinder

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #28 on: April 16, 2008, 04:23:59 AM »
Looking again at the diagrams - are there any controls on this - in other words, how can you control it now ??

I can see a slot for a parrallel port - what is that for.
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Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #29 on: April 16, 2008, 08:35:54 PM »
Ok, I understand what needs to happen here to make the system work. As Jim said, I need to find how it is all going to connect together. Jim, yes there is a controller, they call it a pendant, it is a DOS based computer system that connects to the panel shown above, it works, just doesn't do what I need it to do and will not accept large quantities of G-code. I have considered drip feeding it as well but I think it would be better to just upgrade as much as I can, please correct me if anyone has another suggestions.

I emailed the company that made it back again and asked if the servo drives would accept step and direction inputs, here is his reply

"The motors on the MX3 unit are DC motors not stepper motors. They use a variable square wave signal from the computer to move and to control direction of movement. If the signal is longer in the positive direction than the negative,  the motor will move forward
in the positive direction,  etc.
Tip: The  "brain" for the MX3 is equivalent to a desktop computer, but it contains a special plug-in board that controls movement of the motors."

The special plug in board sounds like a controller board to me? This would be taken place by my PC, Mach and the smooth stepper wouldn't it?

Does the "variable square wave signal" sound like step and directional inputs?

Thanks again all of you for your help,

Scott