Re: [CAD_CAM_EDM_DRO] Driver / Controller

David,
I couldn't get to your link, It said "input Error" at the e-bay site
even if I put the whole "unwrapped" link ext in the browser. I can only
assume that by description, you are looking at a device that takes
"signals" and turns them into motion... A motor "driver".

With typical "hobby" PC based controller software, three techniques are
applied. "Step and Direction" Signals are sent out of your parallel port
to "motor Drivers", which in turn tell the motors where to go and when.
This happens when a software designed to do just that, turns common
G-code text files into those pulses and signals. This is typical of
MACH1, Master5, TurboCNC, YeagerCNCPro, Larken, KCam, Jala, IndexerLPT,
Microsystems.... Who'd I miss?

Then you have the Proprietary "Card" method. An ISA card is placed in
the PC. The Proprietary card handles the Signal Generation, supposedly
allowing "realtime" operation seperate from the PC's Processor. (funny
thing though, these seem to be the most fussy about background Processor
operations..) A cable from the proprietary card goes to the drivers.
This is typical of Ah-Ha, and Microkinetics..... Who'd I miss ?. If you
have not noticed, ISA slots are almost non existant, and there is much
reported knowledge that has to be understood to port these type of
applications to recognize PCI slots. I know many get by with the really
old computers that people are tossing out, but at the super low cost of
new computers or barebones kits, I prefer to stay with the times and the
intercommunication that allows.

The one other technique, One that I personally feel is the most
universal, is that proprietary signals are created from your G-Code and
then sent out of your Serial port to a "signal generator", succesfully
taking the critical timing work OUT of the hands of the PC processor
(this is WHY I can browse the web while my machine is cutting with
FlashCut!), and from that signal generator, Step and Direction signals
are sent to your motor "drivers". (watch for this method to move to USB,
USB2 and Firewire as the Serial port literally disappears over the next
year, Parallel port to follow, then again it looks like USB is dated! )
You will find FlashCut, WindeskNC and also a new development underway by
"Gecko King" Mariss, to be the only ones doing this that I know of.

Now, all of this may be way different than ANY of the machines you have
worked with all of those years because this "level" of control all
revolves around "Step and Direction" signals.

Direction Lines: When a "pulse" goes "high" (+5ttl) or "low" in your
direction line, it has an effect, or literally Tells the direction your
driver will turn the motors. Each drive mfg seems to have their own idea
as to what is best, in regards Low or high.....

The "Step" lines then send out pulses. These pulses dictate the
distance your drivers move the motors. You have the option in stepper
systems to dictate just how far one "step pulse" moves your machine
first by Final gearing: how far one motor "notch" actually moves the
machine by final gearing, and you also can adjust this by "microstep"
settings in the driver, where you can effectively say I want 10 pulses
to move my 200 (1.8degree) one single "notch".

To add to the problems with step-dir compatability, Now, we add in the
variances in Driver pulse "timing" requirements. Some demand that the
Step or Direction change indication happen on the "trailing edge" of
that signal. Others want the indication on the "leading edge"......Then
they all want different "pulse widths" so the drivers can have time to
"understand" what they are supposed to do !

Wide Pulse widths like some MicroK drives at 65uS, will eat up your
Controls maximum pulses per second available, unfortunately lowering
your ultimate top movement rate. This will not matter so much on a
machine that will not run at high feed and rapid rates .

On the other end of the "width" spectrum, Tim Goldstiens API's which
require only .05uS to understand what to do. Big difference ! I forget
just what Geckos require but I think they are similar.

If your goal is to end up with Servos, at this "hobby" level, you are
just taking the "step-Dir" signals primarily designed to run stepper
systems and "converting" them to work with Servo Drivers specifically
designed to take "Step - Dir" input. This is popular using Gecko Servo
Drivers. ( great reading on that Gecko Site !)

Far different than those $10k controls you have been used to! I do not
think anyone has a True Servo Control anywhere financially available in
this "hobby" market. ( I call "hobby" control under $1500)

Depending on Cost and sophistication, Some step-dir "servo" driver
setups only give you an indication "when" the machine has gone outside
of the parameters you told it to run in. Outside of that, it just stops
and tells you it is in error. Very few controls at this level actually
work with encoder data to continuously "correct" error, but daily
advancement is made in that arena... I just do not know much about it
because other than Stepper Noise, I've been very happy with Steppers.

Far as I know, Xylos are just "drivers", waiting to take signals from
your PC, or Dedicated PIC, and turn that into the right Voltage
direction and adequate Amperage delivery to the motors.

I'm far from an Expert, but something I said above should make sense :-)
If not, hopefully someone else will jump in and slap me into shape.

Chris L

volitan712003 wrote:

>I'm sorry but I'm still not "getting" one thing and I hope someone
>can help.
>
>The difference between a DRIVER and a CONTROLLER.
>
>For example, if one of you experienced people were to buy something
>like this cool looking thing:
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?
>ViewItem&category=25286&item=1923982111&rd=1
>
>You'd notice that it clearly states: "Pack Driver - Stepping Motor
>Driver"
>
>Would you then expect to hook a controller up to this? Or would you
>expect to make a cable from your PC right to the Pack Driver unit?
>
>PC -> Controller -> Driver -> Stepper
>
>or
>
>PC -> Driver -> Stepper
>
>I don't know why I can't get my head around this, is sounds fairly
>straightforward.
>
>Also, would the Xylotex units be considered a controller and a driver
>in one?
>
>Thanks
>David
>
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