Cool tables and spindle ordering fun #6 - Brakpan, S.Africa

[Kobus_Joubert]

Nils, I have just come in from the shop. I cut the 6mm BEE file that was posted a few weeks back. The only difference is that I had to re-calibrate the machine and is still feeling my way around tuning the motors in Mach and using the setup of each tool in Vectric to give me a cut that I am happy with. The cut quality is the same from what I am used with when it was driven by Gecko's.

Now that I can monitor the volts and amps on the power supply I can see what my machine draws. When cutting the bee with a 3mm straight cutter at 2.5mm per pass it never went above 3 amps.

After 45 minutes cutting, everything was a nice temperature...not hot at all. Even running 38 volts compared to 52 volts previously, no speed problems.

So far I am very happy.

My other concern was the lack of Gecko's to respond to my e-mail when I had that failure a while ago. I asked them some questions and up to today none was received. Like Hennie said...nobody can work on this thing and when it fails, you simply throw it away. Compare $48.00 to $148 for a Gecko..... I will go for the $48.00 any day....and have a couple spare in case one fails.

[Belli]

Howzit Kobus,

Yesterday you were on Mechmate and today you are all over the world! ;-)

http://www.cnczone.com/forums/showthread.php?t=106893

Groete,

[uirobot]

Excuse me, we are trying to build up integrated stepper servo system. Hello Kobus, please show them you can spare the control box.

[Kobus_Joubert]

Hi Greg, want one to test ? Did not see that yet on CNC Zone.

But I am still in Brakpan having problems getting my Bee together. Anybody please help as to what goes where ? I am stupid with 3D and drawings as you all know.

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[liaoh75]

Kobus, please keep up updated on your testing. I might be next on board. Second build will begin soon.

[sailfl]

Kobus,

Thank you for taking the time to respond to my question. Saving money is important but you don't want to scarfice performance and it looks like that is not a problem.

Please keep posting what you are finding as you test the units.

[Belli]

Kobus,

Are you going to hook up the 5th Axis to your BOB now? Much easier than swopping the wires.

"Excuse me, we are trying to build up integrated stepper servo system." - I consider myself k*ked out!

Groete,

[Kobus_Joubert]

Not to worry about my little bee. My eldest son sat down and in a couple of seconds sorted it out.

I am thinking of putting in a permanent analog amp meter.. like the idea to monitor the amps...will look impressive I think.. maybe one on each motor and then one on the total current drawn.

I might just do that now Greg. Let me first play with the extra drivers, then maybe one will get a permanent place in the control box.

I told Tiger in an e-mail that I don't see us walking away from a BOB as it has many extras that we use to switch the spindle to e-stop and proxys.

[hennie]

Kobus as I was saying earlier. If you take four of the drivers and place them on the aluminium heat shield the size of the fan 120mm x 120 mm and mount the fan under then, 1 you save space in the control box and 2 they are on top of the fan so heat shouldn`t be a issue.I can`t fit them on my motors as they are round and I am still thinking that I would use the same motors as the ones I used on #23 with the gearbox as up to now they have been giving good service.

I had a client the other day ( another kitchen company competition)that needed something .I did made the item for him and guess what he gave me the wrong measurements so we made another one according to the right measurements. guess what he only wanted to pay for the right one and how can I charge him for his mistakes.Dam if the MM is right you pay for both and did my kids enjoy this afternoon

[Gerald D]

I don't see the argument for mounting them on the motors in our application. Why lengthen the sensitive signal cables and shorten the power cables?

[MetalHead]

Good thread !!! I am looking forward to this one !!!

[smreish]

Gerald, I agree with the motor mounted drives. I was just thinking about application that were not MM specific when mounting these little buggers to the drive. Keep the control wires close to home in the cabinet is a grand idea.

[hennie]

Out of sight out of mind.

[Kobus_Joubert]

Ok, Saturday I was busy...had to cut some stuff for a friend..

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And we had to prepare for my son's 21 birthday party, so testing of the driver attatched to the motor was delayed until today.

Mounted everything....

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But as we expected running 5volt signals ove a 10 meter CAT-5 cable does not work for us.

Voltdrop on the 38 volt was not the problem....measured it and it stayed 38 volt at the driver/stepper combination. Giving the unit pulses to jog, there was some 'jitter and hum' but not movement. Direction I could feel it wanted to change, but it did not drive the motor.

Put everything back to NORMAL and she was singing again.

[riesvantwisk]

@robotdigg:

From what I understand from kobus is that the 5V signals don't arrive in a good conditions at the drivers, this is properly due to the voltage drop in the cable.
Controlling the drivers by RS232 (signals I assume) doesn't make to much sense IMHO, the maximum distance given by RS232 spec is 15m, very close that the distance from control box to our actual drives.

Do you have any drivers available that can be controlled with RS485 signaling? Just out of curiosity..

Ries

[PEU]

Mach3 does not talk to CAN/RS232/RS485 for controlling the steppers, my doubt was confirmed by Kobus, long travels for signal levels aren't a good choice, these drivers are just one more alternative to pricey geckos

[bradm]

robotdigg, I think you misunderstand how Mach3 works. Do you have any evidence that Mach3 works with CANbus or RS232 or RS485?

Unless you can produce a demonstration of that configuration, please don't state that it will work.

Note that many of us would be very happy to see such a configuration work, but we need to see the evidence, as there are technological obstacles to overcome.

[riesvantwisk]

robotdigg, I think you can buy Mach3 straight from the internet.

@pablo, I think it's possible to still use these if the BoB can do a better job in sending signals. One could think of drivers that drives the steppers using current, rather then voltage this will then prevent the voltage drop, and it will work over long signal cables. However, that means you need to make some electronics...

[PEU]

Originally Posted by robotdigg

Pablo,

Our CANbus use simple ASCII orders. So Mach3 can talk to it as our basic driver.

No it can't, at least not in the current stable or develpment releases. Mach3 only sends realtime step and direction signals to drivers.
Mach3 is designed to work with a parallel port or motion controllers like smoothstepper.
The only way I could imagine these serial drivers could work with mach3 would be to have a board in the middle with some intelligence for motion planning, but this would nullify the price difference...

@riesvantwisk of course, but the BoB's that we use do not have this capability


Here is a Mariss post about a serial controller he is developing:

Hobby applications use either the parallel port or USB. Both are limited to a 6' (2m) cable length from the PC to the drives. This is a very limiting requirement.

Sending sub microsecond-wide step pulses over a limited physical interface (printer port) or from a USB controller to a cable can produce problematic results. Our conclusion these signals shouldn't be sent over cables at all; they should remain board-level for maximum reliability. There is no CRC error checking or correction for a STP/DIR interface.:-)

Secondly, a STP/DIR interface requires the presence of a PC or a PLC. This places an unnecessary burden on many applications. For that reason it's much better to have the motion control integrated with the drives.

Our goal is to develop a whole new series of step motor, brush servomotor, BLDC servomotor and step servomotor drives using integrated controllers. The GX (G540 variant) is the easiest and quickest way to develop the hard lessons we will have to learn on this new path.

We build drives that are better than most but they are hobbled with a STP/DIR interface that is fast becoming obsolete. Someday Mach3 or EMC2 will also have to have a modern controller interface. We can't wait for that day anymore so we are moving on.

http://www.cnczone.com/forums/showpo...7&postcount=13

[riesvantwisk]

I have read Maris his post, and although it looks very interesting, I think there is plenty for Mach3 and EMC still. From what I read is that he wanted to push some of the responsibilities from PC to drivers, specially the step/dir pulses to be closer to the drivers.

This is all nice, but you still need a G-Code interpreter (not easy at all!) and I wonder how Maris is trying to make it compatible with some of the (Semi) hobby controllers like EMC and Mach3 for motion planning. I don't read anything about feedback using his board, or he is planning to use parallel again? But some switches or devices must be read in near real time that can be done very well in Mach3 or EMC.

it's something to keep an eye on it though...

[bradm]

It's worth noting that the RepRap people have long been directly interpreting a simplified GCode in their microcontrollers. Of course, they're using relatively large and powerful microcontrollers that are a bit more expensive.

http://reprap.org/wiki/Mendel_User_Manual:_RepRapGCodes

Once you abandon G2/G3 and all the canned cycles, it gets pretty easy. Also note that the RepRap toolchains (several options) generally operate by having the host do the heavy lifting to convert to simplified GCode, and then spoon feed it to the microcontroller.

The RepRap world is arguably ahead of the Mach3/EMC2 world in this area. Not robust yet, though.

[MariusL]

Originally Posted by Kobus_Joubert

Hi Greg, want one to test ? Did not see that yet on CNC Zone.

But I am still in Brakpan having problems getting my Bee together. Anybody please help as to what goes where ? I am stupid with 3D and drawings as you all know.

Attachment 9823

Kobus I think I have a photo of your Bee. I will look for it. I made many 3D items.

[Kobus_Joubert]

Hi Marius, Nice to hear you are still alive. Bee is together thank you, but if you have CLEAN vectors of others they are always welcome.

[MariusL]

I will put some together for you.

[KenC]

Originally Posted by robotdigg

Sorry, my misunderstanding.

If that way, please try out our CANbus stepper controller.

Please pardon my ignorant, is this the same protocol you are referring to? CANBUS Wiki

[riesvantwisk]

robotdigg,

if it's done like that, how do you then keep 3 motors perfectly in sync? With perfectly I mean if I need to make a 45 degree line, I need to pulse two stepper motors at exact the same time. With using USB->RS232 converters this is impossible, unless you can make some 'global' 'pulse now' code.

The only 'solution' I can image is make a parallel port->CAN converter and drive the CAN protocol through software, but honestly, that doesn't sound right, and I wonder what the maximum synchroniz(over our 3 motors) pulse frequency would be.

Ries

[KenC]

Originally Posted by robotdigg

Yeah, you are right we have "global command"
We give every motor and controller an address, and then control individually one by one, if we want to control synchronously, you just need to give global command. One Converter correspond to 112 motors and controllers at most.

This information is not useful to a layman like me to understand.
Would you kindly elaborate on how the system is connected for MM use? such as
How many converters are required,
where should the converter be located, near the PC or on the stepper motor driver?
how we can connect the E-stop circuit?
how the limit switches are wired up?
What motion control software can or needed?
how to interface with our VFD?
Can we use EMC2 or Mech 3?

[riesvantwisk]

ken,

in short... I don't think that the CAN controller is any good for us.
You could connect this in EMC if you know your programming languages (I could...) but for sure not in Mach3.

[Kobus_Joubert]

Another busy Saturday for old Big Blue Brakpan.

First did some coasters from Oak.
Then had to cut some 75mm wheels for a friend. Check how smooth it cuts without gearbox reduction.

Then I wanted to make a 1200 mm diameter plate ...why... just because I can.
Did not have enough wood of the same thickness as my thicknesser is in Hospital.
Decided to make a 500mm diameter plate with a bread logo. Not cut out yet, but will finish it tomorrow after the 1000Bike Show that I plan to go to with my son and our OLD bikes. http://www.classicmotorcycleclub.co.za/1000bike.htm

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The little meter was salvaged from the work scrap room. Calibrated with a digital meter. The 0 - 10 middle scale is what I am working on. Very nice to see the AMP's while you cut. With all 4 motors running it average about 5 Amp. When I was using the 12mm cutter the TOTAL amps went up to just above 6 Amp total.

Video at YouTube ... http://www.youtube.com/watch?v=fPbj0c_Ao1o

[Kobus_Joubert]

Bought the files. As with most DXF file, the vectors were not CLOSED. Also found them to have lots and lots of POINTS. But with the help of Vectric V-carve PRO quickly fixed these issues. Decides to shrink them for cutting on 6mm ply that I had available.
Not a bad buy I would say. Thanks Fabrice

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LOOK MA, NO GLUE !!!!!!!!!!!!!!!!