Re: [CAD_CAM_EDM_DRO] Re: Analog Output controller?

Jon Elson <elson@...> wrote:
vrsculptor wrote:

>>Ideally I'd like to have closed loop, where the computer knows the
>>position of the motors, but open loop like the stepper systems is
>>fine too.
>>
>>
>>
>I would go for a simpler non-integrated approach using generic
>stuff. PC based boards are expensive to buy or repair. If you build
>from inexpensive blocks the pieces are cheap and if you blow
>something (and you likely will learning) you won't break the bank.
>
>Rutex sells an R991H driver that accepts step and direction signals
>and outputs a +/- 10 volt signal to control the axis. Cost about
>$100. The Rutex needs an encoder connected to the motor/screw in
>order to monitor its speed. USDIGITAL.com encoders are about $50.
>
>http://www.rutex.com/us/cart.php?
>target=product&action=view&product_id=15&category_id=5
>
>Mach2 controller software ( www.artofcnc.ca ) @ $150 can drive up to
>6 axis using step and direction signals. It's not rocket science. I
>figured it out and its working fine.
>
>

The Rutex convertor does not bring position info back to the computer.

Mach2 does not continuously monitor actual machine position. It apparently
reads the machine position with software (can lose pulses at higher speeds)
and will switch to the read-back position when the machine goes to e-stop
mode. (What a kluge!)

Jon


Thats a good point you make Jon. However, in 14 months of using Mach2/Bridgeport on a daily basis it has NEVER lost position during normal operation. I'm sure it could be modified to keep up with position when powering down but, is it really necessary? I just set my handwheels to zeros with machine zeros at night if I'm running the same setup in the morning and make sure its still in position in the morning. Losing position during an E-stop is not that big of a deal, it only takes a few minutes to reference out again. Its hardly fair to discount Mach2 because of this one feature, it has many others that more than make up for it.

Ron








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