Re: [CAD_CAM_EDM_DRO] Servo hardware Was: EMC2 Servo Loop

Jim Register wrote:

> On 12/22/2010 11:38 AM, Jon Elson wrote:
>
>> timgoldstein wrote:
>>
>>> Not so much an EMC questions, but more the hardware to do an EMC setup.
>>>
>>> If I wanted to set up a small mill or lathe that most commonly used 250 oz/in or so NEMA 23 steppers, can anyone give a list or suppliers and part numbers for a true closed loop servo setup. If I am understanding correctly it would need motor, servo drive, encoder, servo card/interface hardware, power supply.
>>>
>>>
>>
>
> Jon,
>
> That doesn't close the loop in the PC, does it? I thought that would
> best be done with either your product or Mesa's for the encoder counting.
>
>

Oh, HELL! I skipped right over the part about true closed loop! I just
saw "small mill and steppers".

OK, the problem here is that there really is no such thing as "true
closed loop" with stepper motors. You can get error detection, but you
can't do anything about it except declare a following error and halt.
That's better than blindly going on after steps have been lost, but a
stepper drive cannot recover from a stall until you come to a complete stop.

But, if you are willing to replace the motors, too, then there are options.
I have a universal PWM controller that closes the loop through the PC.
I have brushless servo amps, and am now carrying some brushless motors
from Keling. These are size 23, but are so insanely powerful you won't
believe it. I don't sell power supply components, but can recommend
where to get the parts. The power supply is simple.


So, the kit for 3 axis is :
1 Universal PWM Controller $250
3 brushless servo amps 450
3 brushless motors with encoders 360
total $1060


You can see these products at
http://pico-systems.com/oscrc4/catalog/index.php?cPath=3

There are various other options, such as to add a jog pendant, spindle
encoder for rigid tapping, spindle speed control, etc.

Thanks for the heads up that I answered the wrong question!

Jon