Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: graymachine on May 09, 2011, 03:18:58 PM
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Hi, I have a commercial cnc lathe I'm thinking about running with Mach3. I have done searches with no results, and other than reading every thread,
is there anyone who could answer some basic retrofit questions?
1: I have analog dc servo's with resolver encoders and need to figure out exactly what or what kind of servo interface card, motion controller, breakout board,
quadrature encoder, etc., I need to get them to work with Mach3.
2: Can I use my existing operater panel for all the buttons, switches, jog wheel, etc. (manual functions - spindle off/on, collant off/on, tailstock fwd/rev, jog x z,
home, work light off/on, tool changer)
Thanks for any help, or point me in the right direction.
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Not really easy to answer these questions without being a bit vague I am afraid.
1. There are several motion controllers for Mach that can integrate with analogue servo amps, Galil, DSPMC, Kflop/Kanalog and then there are the YASPC cards which I believe are kind of DIY boards.
I think for all you will have to replace the resolvers with encoders or get resolver to encoder interface cards which would likely be more expensive than just replacing the encoders.
Depending on your motor type/specs you may be better to replace the drives with ones that can accept Step/Dir input but whether that is the best option or not all depends on what you actually have.
2. You can most likely use the panel again but it will need rewired to interface with your chosen motion controller, so basically you can use buttons but probably not the way they are connected at the moment.
Hood
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Hood, thanks for the reply. If I just replaced the servo's with steppers, where would I be?
Would I still need an encoder to guarantee proper position?
Would I still need motion controllers or does Mach3 do that?
Do I understand correctly that a breakout board is optional but offers protection to your pc.
Thanks.
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Hi
Here is a link to my Colchester refit.
http://www.cnczone.com/forums/viper_servo_drives/82579-colchester_master_anilam_viper_200_a.html (http://www.cnczone.com/forums/viper_servo_drives/82579-colchester_master_anilam_viper_200_a.html)
My refit was not as complicated as your lathe with turret and tailstock but may give some ideas.
I kept the brushed servos. The old thyrister drive exchanged for step / dir drives - the resolvers were replaced with encoders.
Any of the control gear / contactors / breakers etc were re-used too.
I wouldn't exchange to steppers, as you would need new motors and drives - I think you would be better off keeping the servos already fitted and go for new drives.
Much of the wiring "should be" back to the panel already.
Some photos of your lathe would be great.
ATB
Derek
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Hood, thanks for the reply. If I just replaced the servo's with steppers, where would I be?
That to me is a backward step. Steppers have their place but I am presuming your machine is a medium sized mill and for that servos are superior. I have had a Bridgeport CNC with steppers but also have a Beaver NC5 with servos. The rapids are 4 times greater and could be more and the acceleration (most important in my opinion) is 8 times more with servos.
Would I still need an encoder to guarantee proper position?
Mach is open loop and to guarantee your axis is in the position Mach tells it to be is to have servos with encoder feedback and the motors/drives need to be tuned well to allow a small following error to be set. If you had steppers then as long as they are properly sized they are accurate but there is no real guarantee that they will be where Mach thinks they are. But as said if they are properly sized then the likelyhood of them not being where Mach thinks is very minimal, the only time that has happened on my Bridgeport was when I tried to rapid through the vide ::)
There is a board sold by Ron Rogers which allows you to hook up encoders to monitor the commanded position and the actual position and fault Mach if it is outwith a user set following error but to me it is not really a great idea. Sure it will stop if you are out of position but if that is the case then your steppers are not up to the job so thats all that it is really telling you. Of course others may have different opinions on that ;)
Would I still need motion controllers or does Mach3 do that?
If using steppers then the parallel port could be used, this could also be used if using servo drives that can accept step/dir input but if your encoders are high count then rapids could be limited. I get over this issue by using the SmoothStepper, it pulses externally to Mach and is a very smooth pulse of up to 4MHz per axis.
Do I understand correctly that a breakout board is optional but offers protection to your pc.
Thanks.
Depends on the way yougo, if using one of the cotrollers mentioned in the first post they will likely need some form of making easy connections. If using the parallel port or the SmoothStepper then again a BOB makes connections easy. Most BOBs can also buffer the parallel ports voltage which means you can use the modern computers 3.3v ports and the BOB will buffer it to 5v.
So to answer your question, a BOB is probably best but not always needed but is a big convenience.
Hood
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Oh sorry see its a lathe ;D but my points probably still apply.
Hood
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BTW what size/type/make lathe is it. I have done a Churchill Computurn 290 lathe which is around about 3000Kg and can swing 500mm.
Hood
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Thanks everyone for the reply. My lathe is a 1986 Mazak QT10 Universal with Mazatrol T2 controller. (Universal means it has a tailstock)
It's rated at 10" swing, 20" between centers, 8 position turret, programmable chuck and tailstock. The whole problem started when the
spindle controller went out. Apparently it shot some high voltage back through some of my controller boards. I replaced the spindle
controller with a VFD and can run the spindle manually, but with bad boards I cant get the rest of the machine to function properly. I
have replaced some of the boards, but obviously not the right one, and they all are going out one by one anyway. It has dc servo's on
X and Z axis. I think 25 years is enough for the controller electronics and it's becoming a money pit. The pc controller looks like it would
do the job and appears simple enough. I just want to make sure I know what I need before I start buying stuff.
A list of everything I need would be helpful. I already have the pc with Mach 3 running good on it. Next step is to deal with the dc servo's.
Thanks.
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Sounds like you are thinking of replacing the amps(analogue drives)? If so then Specs of DC servos would be needed to advise which drives may be suitable.
Depending on which controoler you choose or if PP or SS then it will be likely you will need a PLC for the extra I/O you will need for things like chuck, turret etc.
I have two 6 position turrets on my lathe, originally it had a rear 6 pos turret and a front 4 position toolpost but I replaced the toolpost with a turret I aquired from a friend who was scrapping a fire damaged bullard lathe.
Hood
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Hood, Is it possible to keep the analog drives I have now and the board in my existing controller that sends the signal to them
and add a step/dir to analog converter card in my computer. My drives still work good. I can home and jog just fine with them
now. I guess I would just be replacing the brains and plc of my controller with the pc running mach3. That would control
my spindle, turret, tailstock, coolant, chip conveyer, chuck, and send a signal to my drive board. I could add the external plc
if i had to.
Thanks.
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Yes, if the drives are good then its likely the way I would go also. You would need one of the above mentioned controllers though. The YAPSC can do Step/Dir to analogue but I dont know much about them and have not heard a great deal but a search on the CNC Zone may bring you some answers as I think that is where most activity on them is.
The KFlop/KAnalog would maybe be the way I would go although DSPMC also seems good but more expensive. Having said that I have a 4 axis Galil here that I bought on eBay a while back so maybe that would be the way for me.
Suppose it all depends on you, have a look at the Kflop/Kanalog and DSPMC sites and see what you think, the Galil site may not help you much but there are sections here for Galil which should give you info, also section for DSPMC but dont think the KFlop/KAnalog has a section here.
How does your turret work? is it all hydraulic or standard DC motor or servo? Also tailstock, is it hydraulic or servo driven for positioning?
Hood
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Does what I'm thinking make sense. I could just take out all the other boards in my controller box and leave the one
that drives my dc servos. Basically remove the brains and use mach3 as the controller. Would I need an add on plc?
Also, what would you want for the galil 4 axis card?
Thanks.
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If you are meaning the servo Amps then yes you would need to keep them but if you are meaning a board that is in the control that sends the analogue voltage to the amps then its unlikely you could use that with Mach.
If using something like the DSPMC or Galil or possibly the KFLOP/KAnalog then you will likely have enough I/O from them to not need a PLC. I must admit though personally I like a PLC as ladder logic is relatively easy and very configurable and makes integration simple.
As for the Galil it probably wouldnt be cost effective for you buying it from me even if I was to sell. I am in the UK and paid £150 for it and with postage to the USA I am sure you would get one cheaper on eBay in the USA. The downside of the Galil for me at this point is the breakout boards are fairly expensive and certainly in the UK they are very scarce on eBay, the USA may be different.
Hood
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Oh as a side note, check with the Galil part of this forum as to which models are suitable as not all are. The one I have is a self contained unit but you also get PCI card versions which work with Mach. The older ISA ones dont as far as I know but maybe that has changed.
Hood
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Please forgive me for being a little slow on terminology. I have been running these things for years
and letting other, more qualified people work on them. That's all different now.
When you say "servo amps" you're talking about the power amplifier that sends the required amperage
to run the servo motor? The actual controller board in my controller box would be replaced by the
galil or equivilent driver card?
I understand about the galil card you have.
Thanks.
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Servo Amps or Drives, one in the same although Amps (amplifiers) are the more usual term for the old type that these machines of that vintage tend to have.
The amps are likely to be a series of cards, one or more for each axis although they may be multi axis cards. They will likely be in a rack in your cabinet and also likely to have a power supply in that rack. That is what you will need to keep but the brain part of your control will be what is replaced by Mach and the Galil, DSPMC or whatever.
Hope I am explaining it OK but if not ask more as its not easy for me as I am also not a technician so just learned as I have gone.
Hood
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Galil cards of the ISA variety work as long as they are of the 17XX series.
The 10XX series don't work.
I also have a USB Galil controller and it works. The PCI and Ethernet varieties work as well.
The Galil controllers should work well on your lathe up to the point of threading. Threading is being worked on but is not yet ready to be released.
The 5 and more axis has lots more I/O than the 4 axis or less units. If you buy the board to control the extended I/O then you will have plenty.
The DSPMC, of which I have 2 of, works real well and is supposed to be able to thread but I don't have one installed on a lathe(yet).
DSPMC V2 has 96 I/O which should be more than enough for any lathe and most mills. Pricey when you get the 4 breakout boards but industrial strength.
The Kflop, of which I have none, is another analog output option that supports threading. Looks like a good bit of kit but again I have no personal experience.
HTH,
Mike