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  1. #1
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    Default Servo motor setup

    Hi all,
    Am back in the process of rebuilding a large plasma table, and am changing to servo setup,
    Just few questions
    What is the best for smooth results
    17 or 20 bit encoder's. ??
    I need about 400 watt,
    I have real good gear boxes on table
    The old motors was brushed, using tachometers,

    I would like a simple setup where I could buy motors, drivers and what ever else is required.
    and preferred something that is easy to
    set up
    Any ideas where I could purchase from, and somewhere that won't cost the earth.

    Similar Threads:


  2. #2
    Community Moderator Al_The_Man's Avatar
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    Default Re: Servo motor setup

    A lot depends on what controller you are using?
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  3. #3
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    Default

    Hi Al
    I have no controller purchased as yet,
    But have been looking into the
    fangling F2500TF-B controller, made by a chinese company
    It seems to have alot of options on it,
    With also THC built in, not sure how good it will be,,



  4. #4

    Default Re: Servo motor setup

    Hi,
    17 bit encoders are more than adequate.

    I have some Delta B2 series AC servos. They are fitted with a nominal 17bit incremental encoder, in fact it is 40,000 line or 160,000count per rev.
    That is serious resolution, excepting really expensive highspeed controllers you'll never be able to exploit all that resolution.


    All AC servos do some version of 'electronic gearing' which allows you to adapt the very high resolutions obtainable with modern servos to some
    lesser amount that is eminently practical. In my case my servos are direct coupled to 5mm pitch ballscrews. I have determined that 1um resolution
    is entirely adequate and so I require an effective encoder count of 5000 counts per rev. Note that this is but a small fraction of what I could achieve,
    but if I can properly and fully exploit 1um resolution I'll be doing well.

    Any good modern servo will have ample encoder resolution for smooth operation. Even cheap Chinese entry level servos all have Tamagawa type encoders,
    or a copy thereof. They have 10,000 count per rev, even they would be perfectly adequate.

    The way you couch your question makes me wonder if you are trying to decide between Delta B2's (17 bit) or Delta A2's (20 bit). As I have just explained
    the extra resolution of the encoder is just too much of a good thing, either will be absolutely fine. One difference between the A2 and B2 series is that the
    later model A2's can have dual position sensing. That is, they use the rotary encoder like all AC servos, but can also monitor another encoder or linear scale
    attached to the load (axis). This is the last word in accurate position control, it includes any lash, flex or lost motion within the position loop without the need
    for a feedback capable (read really expensive) controller.


    I was unaware of this difference when I bought my B2 series servos, had I known I might have been tempted to pay the extra $50 or so to get them.
    As it turns out the resolution of the B2 is way more than I could ever need and I have no intention of fitting linear scales jus to chase that last um.
    None-the-less I would have paid a bit more for them just so that I had that extra capability 'up my sleeve' in the years to come.

    Craig



  5. #5

    Default Re: Servo motor setup

    Hi,
    as you have guessed I like Delta, a Taiwnese brand made in China, quality at a fair price.

    I bought a 400W B2 servo/drive/cable about four months ago for $468USD including 3 day DHL to New Zealand.
    From the same company two months ago I bought three 750W B2's, one with a brake. The non braked units cost $440USD plus shipping to New Zealand.
    The company now send me emails and as a result of their sales they are going to get an even better deal from Delta and they wish to pass
    some of that on, I think you could get a 400W B2 servo/drive/cables for about $380USD plus shipping.

    fasttobuy2012 | eBay Stores
    This company do a brand 'ToAuto' which look to be really good value.

    I'd have to recommend that you buy a programming cable, you only need one to do all Delta servos, which allows you to use software on a PC
    to program the drives, really REALLY good stuff!! I got the IEEE1390 to USB C adapter for $67USD including shipping to New Zealand. Well worth it.

    https://www.ebay.com/itm/NEW-ASDA-B2...72.m2749.l2649

    Craig



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    Default

    Hi Craig,
    That's great info, just what I was looking for
    Good explanation.

    Is it tricky to set up the motors through the PC





    Quote Originally Posted by joeavaerage View Post
    Hi,
    as you have guessed I like Delta, a Taiwnese brand made in China, quality at a fair price.

    I bought a 400W B2 servo/drive/cable about four months ago for $468USD including 3 day DHL to New Zealand.
    From the same company two months ago I bought three 750W B2's, one with a brake. The non braked units cost $440USD plus shipping to New Zealand.
    The company now send me emails and as a result of their sales they are going to get an even better deal from Delta and they wish to pass
    some of that on, I think you could get a 400W B2 servo/drive/cables for about $380USD plus shipping.

    fasttobuy2012 | eBay Stores
    This company do a brand 'ToAuto' which look to be really good value.

    I'd have to recommend that you buy a programming cable, you only need one to do all Delta servos, which allows you to use software on a PC
    to program the drives, really REALLY good stuff!! I got the IEEE1390 to USB C adapter for $67USD including shipping to New Zealand. Well worth it.

    https://www.ebay.com/itm/NEW-ASDA-B2...72.m2749.l2649

    Craig




  7. #7

    Default Re: Servo motor setup

    Hi,
    Is it tricky to set up the motors through the PC
    The servodrive and servo are a closed loop. Thus any step/direction controller will have no difficulty in commanding these servos.
    Mach4, UCCNC, Centroid and LinuxCNC are all worthy contenders.


    Craig



  8. #8
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    Default

    Ok,
    So just to clear things, as am a dummy when it comes to servo,
    Am well experienced in steppers,

    The controller I will be going for is not pc based, but has step dir output control.
    So do these motors have to be setup through a PC to set the speeds/ tuning, or does that be done on the servo driver,
    Or does it be done on the CNC controller, just like you would setup steppers on the like of Mach3,

    Regards Gary

    Quote Originally Posted by joeavaerage View Post
    Hi,


    The servodrive and servo are a closed loop. Thus any step/direction controller will have no difficulty in commanding these servos.
    Mach4, UCCNC, Centroid and LinuxCNC are all worthy contenders.


    Craig




  9. #9

    Default Re: Servo motor setup

    Hi,
    modern AC servos have a programmable drive. There are a lot of parameters to set. In most cases you can set them by pushing buttons on the drive
    like programming a watch, but its a real PITA and mistake prone. Most manufactures offer software assistance that resides on a PC by which you program
    the drive. Once the drive is programmed to your satisfaction you can install it in your machine without the need of a PC. Programming drives with a PC is highly
    recommended.

    The only 2D standalone Step/Direction plasma controllers that I've had anything to do with are cheap Chinese ARM based units. One customer had several, all of them
    blew up eventually and the standalone THC controllers blew up regularly. In the end I convinced him to go for Mach4, a Hicon motion controller with realtime THC
    control and he hasn't looked back. Now Mach4 has a script based THC feature which as far as I'm concerned leaves those cheap and nasty ARM controllers
    for dead.

    As for the Fanuc/Seimens type controllers, well the sky is the limit, I hope you have plenty of money, you'll need it if you want a good industrial control.

    So do these motors have to be setup through a PC to set the speeds/ tuning, or does that be done on the servo driver,
    Or does it be done on the CNC controller, just like you would setup steppers on the like of Mach3,
    Both. In the servodrive you will program absolute max accelerations, velocities, voltages, currents and more. Then in the controller you will have to
    program desired max accelerations and velocities, at least a little less than you have programmed into the drive. It doesn't matter whether the controller
    is a PC type or an industrial standalone type you will have to program it with these parameters.

    Craig



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    Default Re: Servo motor setup

    UCCNC is easy to operate, has realtime plasma THC control. I'm using it on my plasma machine for over 2 years now.



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    Default Re: Servo motor setup

    For servo motor, what is the min speed for servo motor as axis motor ?
    I found on fasttobuy a 1 kw servo motor 1000 rpm with 10 Nm and 1.5 kw motor 1500 rpm with 10 Nm, which one the better to choose ?
    If 1000 rpm speed is enough, I will choose 1 kw servo motor.



  12. #12

    Default Re: Servo motor setup

    Hi,

    For servo motor, what is the min speed for servo motor as axis motor ?
    That depends on your machine.

    If you direct couple the servo to 5mm pitch ballscrews then the max axis speed will be 1000 x 5 =5000mm/min or 5m/min, pretty slow
    for a plasma. If however you have 20mm pitch ballscrews then the max axis speed is a much more respectable 20m/min.

    Note that a 1kW or 1.5kW servo would usually be fitted to a VERY large machine, are you sure that you need all that power?

    Craig



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    Default Re: Servo motor setup

    Note that a 1kW or 1.5kW servo would usually be fitted to a VERY large machine, are you sure that you need all that power?
    I plan to retrofit my cnc lathe Wasino LN 32 A II for X axis and Z axis. She used Fanuc motor 2.6 kw frame 130 on both axis for such small cnc lathe. I will use Acorn CNC for this lathe. I think it will be OK if I replace both motor with 1kw 1000 rpm ? Or I must go with higher RPM motor 1 kw 1500 rpm ?



  14. #14

    Default Re: Servo motor setup

    Hi,
    the rotational speed required is dependant on how quick you wish your lathe to travel. I imagine that with 2.6kW per axis it used to
    move at lightning speed, if you wish to maintain that then get even more powerful/faster servos. If however you are happy
    with the axis speed with a 1000 rpm 1kW servo then use it.


    What pitch are the ballscrews? Are they direct coupled? These questions need to be answered before you can do any calculations.

    Craig



  15. #15
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    Default

    Ok thanks Craig,
    Hopefully Mach 4 is better that the Mach 3 I was running,
    It kept lossing steps, and would take the odd idea of running a straight cut of the parts already cut.

    Quote Originally Posted by joeavaerage View Post
    Hi,
    modern AC servos have a programmable drive. There are a lot of parameters to set. In most cases you can set them by pushing buttons on the drive
    like programming a watch, but its a real PITA and mistake prone. Most manufactures offer software assistance that resides on a PC by which you program
    the drive. Once the drive is programmed to your satisfaction you can install it in your machine without the need of a PC. Programming drives with a PC is highly
    recommended.

    The only 2D standalone Step/Direction plasma controllers that I've had anything to do with are cheap Chinese ARM based units. One customer had several, all of them
    blew up eventually and the standalone THC controllers blew up regularly. In the end I convinced him to go for Mach4, a Hicon motion controller with realtime THC
    control and he hasn't looked back. Now Mach4 has a script based THC feature which as far as I'm concerned leaves those cheap and nasty ARM controllers
    for dead.

    As for the Fanuc/Seimens type controllers, well the sky is the limit, I hope you have plenty of money, you'll need it if you want a good industrial control.



    Both. In the servodrive you will program absolute max accelerations, velocities, voltages, currents and more. Then in the controller you will have to
    program desired max accelerations and velocities, at least a little less than you have programmed into the drive. It doesn't matter whether the controller
    is a PC type or an industrial standalone type you will have to program it with these parameters.

    Craig




  16. #16

    Default Re: Servo motor setup

    Hi,

    Hopefully Mach 4 is better that the Mach 3 I was running,
    It kept lossing steps,
    Mach3 is no more prone to losing steps than Mach4. Losing steps is a classic symptom of stepper overload and no software will
    prevent the laws of physics from taking its toll.

    Having said that Mach4 does have a much more comprehensive suite of features for plasma tables, including a script based THC solution. It is the only
    Windows based CNC solution that does so, all the others require realtime hardware which is supervised by the Window app.

    The script based THC has a very modest bandwidth of around 20Hz, so any system that demands HIGHLY compliant THC will not be satisfied with Mach4's
    script based solution. There are two manufacturers of external motion control boards suitable for Mach4 which support realtime THC, the Hicon Integra and the
    Ethernet SmoothStepper. The Ethernet SmoothStepper in particular is matched to TMC3in1 plasma THC controller.


    With Mach4 then you have four alternatives to enact THC:
    1)Use a Proma Voltage detection unit feeding Machs script based THC (note the bandwidth limitations)
    2)Use a TMC3in1 unit and an Ethernet SmoothStepper for a highly compliant fully featured THC solution
    3)Use a Proma unit and a Hicon Integra which also offers realtime THC and a nice feature set albeit somewhat reduced from the TMC3in1
    4)Use a completely stand alone THC controller that manages the Z axis entire. Cheap Chinese controllers of this description blow up regularly. Good ones like
    Hypertherm cost a fortune.


    Craig



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    Default

    Hi,Craig

    Did you find them B2 servo drivers hard to wire,
    There seems to be alot of pins on the port going back to the controller, maybe 40!
    Are they all used,
    I would have thought 4 pins is defo needed for
    The control of direction for+- etc
    And maybe some pins for axis limits, emergency stop etc

    But I didn't think all them pins need to be used
    ????




    Mach3 is no more prone to losing steps than Mach4. Losing steps is a classic symptom of stepper overload and no software will
    prevent the laws of physics from taking its toll.

    Having said that Mach4 does have a much more comprehensive suite of features for plasma tables, including a script based THC solution. It is the only
    Windows based CNC solution that does so, all the others require realtime hardware which is supervised by the Window app.

    The script based THC has a very modest bandwidth of around 20Hz, so any system that demands HIGHLY compliant THC will not be satisfied with Mach4's
    script based solution. There are two manufacturers of external motion control boards suitable for Mach4 which support realtime THC, the Hicon Integra and the
    Ethernet SmoothStepper. The Ethernet SmoothStepper in particular is matched to TMC3in1 plasma THC controller.


    With Mach4 then you have four alternatives to enact THC:
    1)Use a Proma Voltage detection unit feeding Machs script based THC (note the bandwidth limitations)
    2)Use a TMC3in1 unit and an Ethernet SmoothStepper for a highly compliant fully featured THC solution
    3)Use a Proma unit and a Hicon Integra which also offers realtime THC and a nice feature set albeit somewhat reduced from the TMC3in1
    4)Use a completely stand alone THC controller that manages the Z axis entire. Cheap Chinese controllers of this description blow up regularly. Good ones like
    Hypertherm cost a fortune.


    Craig[/QUOTE]



  18. #18

    Default Re: Servo motor setup

    Hi,
    Did you find them B2 servo drivers hard to wire,
    There seems to be alot of pins on the port going back to the controller, maybe 40!
    Are they all used,
    No, they are not hard to wire, and no not all 40 or so lines are used. You can operate the servo with just four lines, Step and Direction,
    Enable and Reset. Many of the other pins are programmable, for instance you might want an analogue output to reflect servo current, then
    you would program the drive to do so. Then you could hook that output to an analogue voltmeter display servo current, easy!
    You can also program different faults, for example you might want an Over Voltage and/or an Over Current event to cause an immediate Estop
    whereas a Following Error event might cause a Feedhold. Thus you would program the drive to have two alarm outputs, one causing Estop
    and another causing Feedhold.

    Modern AC servos are SO MUCH MORE FLEXIBLE than servos of yesteryear and any stepper ever made!

    Craig



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    Default

    Ok, super stuff
    I'll go ahead and get ordering parts, also will order all the extras showing in wiring ,
    EMI filter
    Electro magnetic Contactor
    External resistor,

    I also have to look into maybe more filters on the entire setup, as the plasma source am using is a
    Hypertherm HT2000,. And they give off quite a bit
    Of HF

    Best Regards


    No, they are not hard to wire, and no not all 40 or so lines are used. You can operate the servo with just four lines, Step and Direction,
    Enable and Reset. Many of the other pins are programmable, for instance you might want an analogue output to reflect servo current, then
    you would program the drive to do so. Then you could hook that output to an analogue voltmeter display servo current, easy!
    You can also program different faults, for example you might want an Over Voltage and/or an Over Current event to cause an immediate Estop
    whereas a Following Error event might cause a Feedhold. Thus you would program the drive to have two alarm outputs, one causing Estop
    and another causing Feedhold.

    Modern AC servos are SO MUCH MORE FLEXIBLE than servos of yesteryear and any stepper ever made!

    Craig[/QUOTE]



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    Default Re: Servo motor setup

    Hi Craig, I bought 4 servo drive and motor from Fast to buy (no name and no information ) , as a nerd in servo I find my self in a dark room with on light around .I'm at the point where my drive are ready to receive code or information but to much confusion and no information around.
    Where to start ?
    what to use as step/dir for motion on controler card .
    Programming servo , noname compagny don't have software to offer , so what to use ?
    Can you give me/us some information or place to go for info .
    Thanks.
    Alain



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