Machsupport Forum
Third party software and hardware support forums. => SmoothStepper USB => Topic started by: XLR84x4 on June 03, 2008, 12:58:26 AM
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I have been struggling with the GREX so it's tie to give it the flick.
Which bob can someone suggest. I wish to run high feed rates of +5000mm/min on a material cutting table using a tangential knifeJason
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Hi,
The idea of the SmoothStepper is to look like 2 parallel ports. So, any of the parallel port BOBs should be fine.
Cheers,
Peter.
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I am also wondering what board to use... I need something without built in features, all I need is screw-terminals, and selectable direction (for pins2-9) and some protection...
i would add relays and fancy circuits separately.
Am I right to suppose that as SS goes from the USB there is no need for charge pump circuity? Or there is still good use for it, to output the ENABLE signal for the drives?
The PMDX-122 looks nice, it is almost what I need, but its price is quite high... (And I am in the EU, ordering and customs is problematic)
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I would certainly recommend the PMDX122, it may be more expensive than some of the others about but the quality is excellent and reliability seems to be excellent. I have them on 4 different machines and the first one was purchased at least 4 years ago.
Hood
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Thanks, Hood!
What do you say for the charge pump issue with the SS ? Can be omitted, or useful to trigger device`s ENABLE?
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Will let others comment on that, dont want to upset anyone again ;)
Hood
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Why would anyone be upset because of your opinion / advice? :)
Ok, So as I am in the EU, I do not have much chance to see such BOB... Since you have them, I would like to ask you (or anyone who has such device) to post a picture of the board// I just want to see the layout, on the web I have not found any good pictures... I checked the user`s manual, too, but it is not clear e.g. where are the LED-s, etcetc...
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I will take a pic today if I remember ;) The LEDs are surface mount so they wont be glaringly obvious on the pic but you will see them once you realise that.
Hood
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Heres a pic of the PMDX122 thats in the Beaver Mill cabinet.
Hood
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Hi Hood, in the above picture I notice that cable from the smoothstepper is not plugged in to the PMDX, was this to make for a clearer picture? Is it possible to provide more detailed pictures or diagrams of the larger layout, just for me to get a better understanding.
Cheers
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Yes thats correct, normally the ribbon cable would fit right into the socket on the left side just beside the centronix connector.
Are you wanting a bigger pic of the PMDX or are you meaning a bigger view of the cabinet and its components?
Hood
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Probably just a wider shot of the PMDX and SS. I've contacted the company that sells this unit and requested postal charges to Australia so I'm close to buying one.
Thanks in advance
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I am also wondering what board to use... I need something without built in features, all I need is screw-terminals, and selectable direction (for pins2-9) and some protection...
i would add relays and fancy circuits separately.
Am I right to suppose that as SS goes from the USB there is no need for charge pump circuity? Or there is still good use for it, to output the ENABLE signal for the drives?
The PMDX-122 looks nice, it is almost what I need, but its price is quite high... (And I am in the EU, ordering and customs is problematic)
Hi,
Have a look at the MB-02 that I sell. It will be in stock by next weekend. It can connect to the Smoothstepper via a 26pin-26pin IDC cable. It has buffers on all inputs and outputs along with a few other features.
http://homanndesigns.com/store/index.php?main_page=product_info&cPath=22&products_id=59
Cheers,
Peter
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That's a nice looking BoB Peter. .. Nice price too!
Checked the link, not much description there. Pretty straightforward.
Is there a pdf for it ?
Can you explain the "few other features" mentioned above ?
Can see the 5v or 0v common, 2-9 as IN or OUT and optional ENABLE.
Also, what is the shipping to USA ?
Thanks,
RC
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No worries Pete, sorry I should have checked you first. I have subscribed to be notified when stock arrives. I have not bought anything yet.
Cheers
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That's a nice looking BoB Peter. .. Nice price too!
Checked the link, not much description there. Pretty straightforward.
Is there a pdf for it ?
Can you explain the "few other features" mentioned above ?
Can see the 5v or 0v common, 2-9 as IN or OUT and optional ENABLE.
Also, what is the shipping to USA ?
Thanks,
RC
RC,
The BOB has 2 enable inputs, one for a logic hi enable and 1 for a logic lo input. Either one will enable the BOB.
The BOB inputs and outputs have pullup resistors. You can set wither they are pulled hi or lo depending on your setup.
The Common jumper allows you to set the common pins to either 0V or 5V depending on your drives, etc.
The D2-D9 jumper allows you to set the parallel port pins D2-D9 to inputs. This is useful for when you are using a 2nd BOB connected to a 2nd parallel port.
The BOB has a USB connector so you can power it off your PC if desired.
Shipping to the USA is about US$15.00
Cheers,
Peter.
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Hi Peter,
Thanks for the info.
Please verify that "It has buffers on all inputs and outputs" implies opto-isolation ?
Regards,
RC
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Judging by the photos that board is not opto-isolated :(
It has a few ICs that act as buffers. The LPT can't sink or source much current, by running through a buffer gate you get the same logic signal but greater fan-out (stringer signal).
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Hey thanks for that Jeff.
Some folks use the terms interchangeably.
I may go another route then.
As I recall, Warp9 recommends isolation with the SS.
RC
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I recommend optical isolation whether your using a SS or not. It is simply the best way to prevent most of the little gremlins from getting into your controls. Some of the Gecko drives have the Step/Direction lines optically isolated at the drive, the G540 has built in optical isolation on all inputs/outputs. So, in those cases your set.
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Hi All,
Appreciate the additional questions and replies as i have been "kind of" looking at BOB's.
A rock solid BOB "without gremlins" is worth the elimination of possible aggrivation even at a increased
price. Not passing judgment, just trying to gain knowledge for down the road decisions.
RICH
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Probably just a wider shot of the PMDX and SS. I've contacted the company that sells this unit and requested postal charges to Australia so I'm close to buying one.
Thanks in advance
Heres a pic of more of the cabinet, not sure its much of a help though.
Hood
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Hi All,
Appreciate the additional questions and replies as i have been "kind of" looking at BOB's.
A rock solid BOB "without gremlins" is worth the elimination of possible aggrivation even at a increased
price. Not passing judgment, just trying to gain knowledge for down the road decisions.
RICH
Hi Rich,
Whether you use a BOB with opto-isolation, is a decision that is made when looking at your system as a whole. If you have stepper drivers that already have opto isolation, then an opto-isolated BOB is likely to introduce problems.
If you are using opto sensors on inputs, then again you don't really want an opto isolated BOB. If your input switches are mechanical, then opto-isolation is good.
So in the end it depends on what other components you plan to use.
Cheers,
Peter.
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Here is another nice pic of a Smooth Stepper installation with PMDX-122's.
http://www.machsupport.com/forum/index.php/topic,6406.msg43351.html#msg43351
Also, in response to post #2. hunserv said "and some protection"...the PMDX 122 is only buffered, not isolated.
Thanks,
RC
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Has anyone tried the C23 board from CNC4PC ?
I am looking into getting that one but it is 198.00 , little pricey BUT after checking out what it has on it , it doesn't seem too bad , It is opto isolated and has 2 relays for motors and vacuum...
I do live in the same city as him but have never bought one or met him..
Any Opinions on this board?
Here is a link http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=182
Thanks
Gary
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Never used that board but my personal opinion on any board and not particularily this one is that the more you have on a board that is sharing the 5v signals to Mach then the more problems you are likely to have. I prefer to have seperate boards for relays etc but this is however just a personal opinion so take it as such.
Hood
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Hi Hood,
So one cable from your SS goes to a PMDX board... and the other one? (which seems larger and uC equipped?)
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That board is the Acustep BOB that CNC Building blocks made (no longer making them).
The reason I used it was twofold, firstly it has Index homing on it and secondly it has differential step/dir outputs. I have been rewiring the cabinet the last few days and have now done away with that BOB as I do the index homing in my servo drives and I have made up a small board that clips direct into the PMDX and converts the single ended Step/Dir outputs to differential.
Below is a pic of the cabinet now(red arrow points to differential board), I welded up a single Aluminium cabinet and everything is now in there instead of two seperate cabinets as before.
Hood
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Neat! Are you using the encoder inputs of the SS as well? Generic inputs, or for spindle encoder?
I have also a single cabinet, but I do not use differential signals. However, I had some noise issues (from freq converter) so I had to shield the SS and the USB cable and put them as far from the converter as possible.
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I have the spindle encoder in to the SS but only the Index pulse will be used at this time. The other inputs on port 3 I will connect to the MPG.
Never had a problem with noise and the SS but I try to shield all 5v signal wires and I use 24V for most things.
Hood
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Hood,
Why would you want to convert the step/dir signals to differential? Did you have problems with them being single ended?
Daniel
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Differential signals are much less prone to noise and as my drives accept them I prefer to use them. I have never tried with single ended inputs as I believe it is better to wire in such a way that the chances of noise are minimsed rather than trying to fix problems at a later stage.
Hood
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I have used C23 from cnc4pc and they work great and have all the features you will ever need, that being said they are horrible running on the smoothstepper. If you are uisng two/one parallel ports they are fantastic, the SS is really buggy it dose some strange stuff and I would not recomend it on a production machine, or if you are cutting expensive material or care about safety. If and when the unit comes out of beta which I doubt we will ever see, use the parallel port until it dose, its not ready for prime time as the beta version suggests. If you need really high stepping frequency you may have no choice, I dont know if the kflop is ready or if it has issues but might be a better alternative.
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Works fine for me on both my mill and lathe, not mass production but used on a commercial basis. From what I see the main issues are with people that have a noisy environment.
Hood
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It must like 50hz better lol.
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Maybe but also a lot of people running on 60Hz with no issues ;)
Hood
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If and when a new update comes out I will give it a shot again, but too many little bugs at the moment and have seen it do dangerous stuff, I dont have any ground loops and the VFD is outside the case and its only supplied with isolated 0-10v and direction line of course. have not had issues on the parallel port as of yet, I just liked the idea of having it usb thats why I tried them, I was hoping they would be out of beta by now and the minor stuff fixed. I fear alot of people maybe left in the cold but I hope not, its like its just an update away from being very good.
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WHat problems did you exactly encounter with the SmoothStepper?
Earlier I payed attention on the GREX, But I did not buy it as it was not ready for what I wanted. SS looked better, but I waited more than a year, till I decided it is good enough to do what I need. Then I bought 2 pieces. Have not regretted so far.
There are no bugs here, But I am not using it on the advanced level. (sometimes when I press buttons repeatedly and rapidly, SS can lockout, bot no other issues discovered)
- Noise isolation has surely to be done carefully.
- High freq Stepping signals have to be handled carefully. E.g. there are not too many optoisolators that can handle MHz ranges...
Don't expect 4MHz performance from a breakout board that was designed to a few kHz range!!! /as with PP/
For this reason I am making my custom BOB, so that it will fill all requirements.
- Tapping, Threading: I do not know how this is, I hope it will be ready by when I need it. I can't imagine however why is it hard to do it, what I imagine: threading/tapping code section should be handled copletely by SS, and it could stream out the step signals for feed directly based on the encoder input from the spindle... why is it so hard? (Mach generates the path, SS just does not give it out based on a standard clock, but rather based on the clock of the spindle input, which better be a quadrature encoder, not just an index signal)
- Expanded I/O: I hope in the near future tis will be available, too.
All in all I am satisfied with the SS, the only thing making me annoyed is that there is no update since the beginning of this year...
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"and it could stream out the step signals for feed directly based on the encoder input from the spindle"
When?
Mach / SS - Just a quess, but the "horse and wagon may need to be able to travel together"
and don't think you will see anything until Mach 4 is released.
Only Warp9 can speak for itself.
There is a post on that site on requesting slaving the spindle to the Z axis, which could be done rather easily, but was limited to only one direction and not both. Haven't pursued it since that posting which was months ago.
RICH
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Well, that was rather a quick brainstorming, I do not know how exactly communication works, but that method would be quite straightforward, but I'm lacking knowledge about what Mach+SS do exactly, that's why I put the question "why'
Slavign spindle to Z? Hard to imagine, the other way around, slaving Z to spindle would be clearer for me. But it's possible that we are talking about the same thing.
Whatever, as I will have no chance to help the development of SS, I am just hoping that soon all those functions will work. (And the I/O expansion as well)
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You got it correct, "slaving Z to the spindle", with the SS. I have have questioned how that is going since it's been 9 months now. Don't hold your breath! ;)
RICH
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I'm patient, and won't need this function in the near future... Maybe next year...
Where is this thread anyway? On the warp9 site?
Thanks!
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Yes, on the warp9 site. I just asked for an update about it recently.
RICH