Re: Advice sought re: driver interface

Ken, I dont think that you have to use inverters at all. The inverter
symbols could be interpreted as meaning that the step and direction
signals are just active on a low input. You could set up your step and
direction software to output high to low step pulse transitions. Of
course the direction line would be set to suit your machine. ie If it
moves the wrong way, invert the direction output (in the software).

I have a parallel interface board available at my website if you are
interested.
http://plaza.powersurfr.com/deanc/db1v20.htm
Your drives could be connected directly to the interface and there is
+5V available for each axis (as well as ground wich would not be
used). The "enable" line to the drive and the "enabled" line from the
drive could also be used if supercam supports it. I'm not really
familiar with supercam.

Dean Couillard
plaza.powersurfr.com/deanc

--- In CAD_CAM_EDM_DRO@y..., Ken Jenkins <kjenkins@n...> wrote:
> I'm a little rusty when it comes to some interfacing
> issues so I humbly cast my inquiry regarding a "current"
> (no pun intended) issue facing me in my Taig mill
> conversion onto the great bubbling pool of experience
> and wisdom which constitutes the CAD_CAM_EDM_DRO group.
>
> I am converting my Taig to Step&Dir using 4 PacSci
> NEMA 34 bipolars and 4 matching 6410 bipolar drives.
> The choice was primarily economical ... the above were
> free ... long story ... interesting ... possibly involving
> South American drug cartels and missing persons ...
> but long ... custom equipment, ordered, paid for, but
> unclaimed after nearly 4 years ... off the books ...
>
> Them: "Ken can you get rid of this stuff I'm tired
> of moving it around"
>
> Me : "Well of course ... if you insist ... (trying
> to keep from grinning insanely) ..."
>
> I'm using the original three motors and phase drive
> which came with the Taig CNC mill (which I bought 2nd hand)
> on my Taig lathe CNC conversion project (ain't I havin'
> fun!!!!)
>
> anyway ...
>
> I'm going to use SuperCAM through PC parallel port to
> handle the S&D to the 6410's. I don't know a lot
> about the electrical properties of the parallel
> ports on a PC and there seem to be a few flavors
> as well. The 6410's inputs are opto-isolated
> (this is good) and PacSci shows a little schematic
> of the interface (see group files section under
>
> http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/
> files/KWJ-files/6410interface.jpg
>
> The schematic shows single input NAND logic gates
> feeding the inputs (which, if you think about it
> is a tad odd in and of itself) and these gates are
> sourced with +5VDC. Now the parallel port doesn't
> have a +5VDC pin. I know there are some on the
> game port (pin 1 for example) but I don't want
> the the extra cable just to get +5VDC from the
> PC (unless I have too). I have built myself a
> breakout box to separate out the 25 signals from
> the parallel port from an old disk drive. As an
> aside, these old disk drives are great project
> boxes. Tear out the 30MB drive and can it, and you
> have a nice metal box, +12, +5, a fan, some connectors,
> an LED power on light, D-power cord connection and
> AC switch. Funny that they are worth more for those
> components than for the drive itself.
>
> So ... finally to my question 2 parts ...
>
> 1. Can I build up a little logic circuit on a board
> inside my HD case to drive the opto's in the 6410
> and power it using the old HD power supply in my
> case even though the logic inputs to the gates
> are coming from the PC (as long as I tie the COMMON
> from my box to the ground pins from the PC) or does
> this create some type of potential ground loop problem
> and a possible source for noise? If anyone wants to
> wax eloquent regarding ground loops and noise issues
> further, you would certainly have my undivided attention.
> I can bring out the +5 off the PC game port but it's not
> as clean as just having the one cable from the LPT port
> by itself also there may be additional logic, limit
> switches that need +5 and perhaps some Solid State relays
> I might add to my box later and I don't know what is
> left over from the PC's +5VDC supply after taking care
> of it's own business. Also I kind of like the idea of
> having some logic ahead of the opto's in the 6410 because
> I know what they can drive whereas I'm unsure what the
> current sourcing/sinking of the parallel port signals
> are.
>
> 2. If you look at the interface schematic referenced above
> two lines are shown terminating in thin air which make up
> the ENABLE function input for the 6410. I can show those here:
>
> | inside 6410
> ?___________ENABLED (collector) _____J1________ | -o 5Vdc
> | |----/
> | | / ---photo diode
> ?___________ENABLED (emitter) _______J1________ | -0 DRIVER ENABLED
(NOT)
> |
> How do I provide the correct circuit and signal to these lines
> in order to produce the ENABLE signal? The signal out from the
> PC (and SuperCam) is ENABLE (logical high sourcing) and I want
> to feed this signal to all 4 motor drives simultaneously.
>
> ok ... 3 parts.
>
> 3. When I do the logic circuits, what are the best devices to
> use? TTL, Low power TTL, Schottkey TTL? I always remember TTL
> being very susceptible to noise especially when there are brush
> motors near by ... or am I just paranoid?
>
> Sorry it's so long ... I figure if you're going to ask a question
> then you're obligated to provide as much info as possible.
>
> Since this is fairly specific to what I'm doing you may want to
> spare the group and respond to me directly.
>
> Thanks in advance for any help, pointers, info,
>
>
> Ken Jenkins
> kjenkins@m...