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Author Topic: Hello 1st post, need advice on controller, board, drivers  (Read 18928 times)

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #10 on: April 05, 2008, 12:09:42 AM »
Honestly, it's a little hard to tell but, if someone was putting a gun to my head, I would say, "Yes, those are Servos".  Steppers typically have 4, 6 or 8 wires to drive them.  Seems like you have more than that inside that 'cozy bundle'.  Plus it seems like there is some kind of PCB board in there which I would venture to guess is your Encoder output.


HTH,
Sid

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #11 on: April 05, 2008, 04:14:21 AM »
Going by the pic of the motor it looks like they are brushed DC servos. Not sure what that is inside as you say you have glass scales then I would have thought an encoder wasnt needed so it could be some form of Tach although Tachs usually dont look anything like that.
 I tried doing a quick search for the motors but cam up a blank but from your specs it seems they are 160V 2.97Amp. I would imagine your drives to be analogue input so you probably wont be able to use them with Mach unless you get an Step/Dir to Analogue converter. You could probably drive these motors with Geckos, Tek10s etc but your top speed would be reduced due to the voltage these drives can handle. There are drives from Rutex that have higher voltage which might be suitable but I have no experience af them.
 Firs thing you really need to do is try and find out from the motor manufacturer as much as you can, also try to find out about your drives, make, model etc.

Hood

Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #12 on: April 05, 2008, 07:58:10 AM »
Thanks, I will check with the motor manufacturer for the exact specs and repost them. In the meentime, on the fisrt page of this thread, last picture, this seems to be one the coordinate sensors, there is one on each axis, do these look like glass scales or something different? If so, are glass scales the best to use or should I be considering something else? Do the "Stepper Motors" have a position sensor on them?

Scott

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #13 on: April 05, 2008, 08:25:52 AM »
Yes they look like glass scales (linear encoders) You could probably use them if they put out TTL with A and B chanels. If not then it would be no hardship to get rotary encoders and fit them to your motors. Your motors may have encoders already and the scales are used as a comparison but I doubt it.
 You have servos by the looks of it, the encoders tell the servo drives the position. You may have tachs on your motors which detect speed of the motors but you dont need them with mach.
 Glass scales are accurate but if you have any play at all in the machine it can cause problems, often it is better to have the encoders directly on the motors.
Hood

Offline jimpinder

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #14 on: April 06, 2008, 02:36:28 PM »
I dont think they are steppers either.

Whatever type of motor you have, basically Mach3 puts out two signals for each axis. One is a step pulse, and the other is a dir pulse. Both - coming from the computer either via LPT1 printer port output, or the new smooth stepper USB output, are at 5 volts.

If, in the end, you decide to replace your motors, then, if you pick stepper motors, you will find that the drives will operate directly from the computer signals. You merely put in a drive voltage from your power supply, and connect up your motors. If you then input the two signal wires (three with the signal return line) to the step and dir inputs, the motors will drive, It is that simple.

I might be preaching to the converted here if you are used to CNC.

Although you can use feedback from measuring instruments to confirm Mach3's position, it does not need any. Mach3 keeps a record of it's own position through the program by counting the number of step pulses it puts out - the only problem is if (for some reason) your motors miss steps. This is usually caused by trying to get too much speed or acceleration on G0 moves - but all in all it is accurate, and if you run well within the limits of your machine, it will be accurate.




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

Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #15 on: April 06, 2008, 09:15:09 PM »
Hey Jim, no I'm not converted, I appreciate all of ythe input you guys have given. I'm no expert, just have some cnc machine experience. I'm finally starting to get how the whole cnc thing works, it's pretty involved, more than I thought. I put my name on the list for a "Smooth Stepper" and I have purchased the Lic for Mach 3, so I guess I'm on the way. I'm not having much luck finding info on the motors that I have and even if I do, I still have to wire them to the new system and I don't have any wiring diagram. Also the circuit board that is in the motor end cap, I have no clue what it is and it was installed by the company that provided the retrofit kit, (it has their logo on it). I think it would be best, especially if  my system will be slow with the servos to replace them and the rest of the drivers, boards, ect. Does anybody have a suggestion for stepper motor size, oz, voltage, amps, ect? They will have to be fairly large to run a bridgeport I would think.

Scott

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #16 on: April 06, 2008, 09:19:00 PM »
If you want fast then you want to go servos. I have steppers on my Bridgeport Mill and get 2500mm/min but on the new mill I have servos and theoretically I could get 20,000m/min
 Steppers are good for smaller machines but as you get up in size servos are the way to go.
Hood

Offline NJC

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #17 on: April 06, 2008, 10:35:13 PM »
Hood, I thought you were saying in a previous post that it would run slower with servos, I guess you were refering to the drivers? Wow, I'm glad to hear that, I just found a schematic of my system, well some of it, it doesn't go into too much detail. You were right when you said the motors looked like they had encoders, they do and the glass scales are for back up. Apperently, the glass scales were an option with the retrofit. The schematic shows the E stop and limit switches as well. This is looking better and better, just a matter of figuring out the details. Is the "Smooth Stepper" still the best option with servos?

Scott

Offline Chaoticone

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #18 on: April 07, 2008, 12:51:24 AM »
Quote
Is the "Smooth Stepper" still the best option with servos?
Yes. You'll love it.

One thing, is it deffinatly glass scales? Not by chance a cover for limit switches is it? Reason I ask, I got fooled on the Hurco a while back. Thought for sure it was glass scales. the way they had those switches in there was nice.  :)

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!

Offline Hood

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Re: Hello 1st post, need advice on controller, board, drivers
« Reply #19 on: April 07, 2008, 03:19:36 AM »
Yes what I was meaning was if your motors are higher voltage that was common on the older DC servos and you ran them from lower voltage drives then your rapid speed would be reduced accordingly. If you can find out what voltage your motors are or even what the power supply transformer puts out then we can go from there. Also have a close look at your drives to see what inputs they have, there is a slight chance they may accept step/dir.
 As Brett says the SmoothStepper would be a good option for you, especially if yous encoders have a high count.
 Hood