Re: [CAD_CAM_EDM_DRO] Re: CNC / DNC
Posted by
Jon Elson
on 2000-05-09 12:40:40 UTC
Andrew Werby wrote:
codes. My
AB will take either, and it needs a particular character first so it can
decide what
code format is being used. You'd need to check the Milltronics
documentation
for that.
older controls had the
paperr tape reader standard, and everything else was an option.
hold the
program, and expect to be able to hold the entire program in memory.
This is a limitation,
as very large programs may not fit.
Backing up is a very important feature, and knowing the last line that
was processed
before stopping or having a fault is really important. EMC is still a
little weak on this,
but one can live with it. The AB had incredible features, so that you
could stop a
program at the end of a move, do manual moves and MDI commands to your
heart's
content, and then resume the program at the next block with two
buttons. There was
even a feature so you could interrupt a move, retract one axis to check,
clean or change
a tool, and then resume the move from where it was interrupted!
vice-versa, so that is
essentially a null-modem. But, X-on/X-off are characters sent through
the normal
data lines, not on other wires. Most PC comm programs handle X-on/X-off
protocols
just fine. There will be a software handshake or software flow control
option to
be set.
control, that should
be fine. That's how mine was set up. I would enter a line like :
READPAPR BORE123.CAM
on the PC, and then hit the AUTO then CYCLE START buttons on the CNC,
and it would
start pulling characters from the simulated paper tape. Each time the
CNC read one
character, the PC would supply the next one.
number.
If you don't have at least operator manuals for the Centurion, forget
DNC, because
you'll never get it working without those manuals. I can't recommend
any DNC
programs, as I only know they exist, but have never used one. The most
important
detail is that they support your Centurion control. Since I didn't have
DNC hardware
or software for my CNC, I went with the paper tape reader interface.
Jon
> This is a muddle. leave out the "output my G-code as step andEssentially right. Some CNC's take ASCII, some take EIA character
> direction
> through the serial port" part, and it makes a lot more sense.
>
> [Actually, that was my assumption, not what the Milltronics guy told
> me. So
> I just have to send it regular G-code, as ascii characters, and let
> the
> mill control do the translation itself?]
codes. My
AB will take either, and it needs a particular character first so it can
decide what
code format is being used. You'd need to check the Milltronics
documentation
for that.
> [But since RS-232 is a serial communications link, I have to goWell, if that is the only interface provided, yes. But, almost all the
> through the
> serial port, no?]
older controls had the
paperr tape reader standard, and everything else was an option.
> A CAD/CAM package (or other machine control) will work a lot betterAgain, depends on the CNC. Some CNC's have a lot of memory available to
> than an
> off-the-shelf comm program. Especially, in some cases, the CNC
> requires the
> tape to be read backwards (to back up a few program steps when a tool
> breaks, for instance).
>
> [You don't get that with DNC, though- it seems like a one-way street.
> As I
> understand it, all I get to do is feed it a set of instructions- no
> backing
> up. But I suppose I might be able to edit the program to resume
> cutting at
> a given place, if I knew where that was.]
hold the
program, and expect to be able to hold the entire program in memory.
This is a limitation,
as very large programs may not fit.
Backing up is a very important feature, and knowing the last line that
was processed
before stopping or having a fault is really important. EMC is still a
little weak on this,
but one can live with it. The AB had incredible features, so that you
could stop a
program at the end of a move, do manual moves and MDI commands to your
heart's
content, and then resume the program at the next block with two
buttons. There was
even a feature so you could interrupt a move, retract one axis to check,
clean or change
a tool, and then resume the move from where it was interrupted!
> [According to the Centurion guy, it's software handshaking: x-on,Unusual, but at least you now know what the flow control is.
> x-off. ]
>Well, you will have to wire transmit data to receive data, and
> [This would come back up the serial port? And the PC would have to
> recognize it? Is this part of the standard null-modem stuff, or
> something I
> have to put in there?]
vice-versa, so that is
essentially a null-modem. But, X-on/X-off are characters sent through
the normal
data lines, not on other wires. Most PC comm programs handle X-on/X-off
protocols
just fine. There will be a software handshake or software flow control
option to
be set.
> [I'm not expecting that- all I want is to be able to run a big programWell, real DNC would be quite nice, but if the PC is next to the CNC
> once.]
control, that should
be fine. That's how mine was set up. I would enter a line like :
READPAPR BORE123.CAM
on the PC, and then hit the AUTO then CYCLE START buttons on the CNC,
and it would
start pulling characters from the simulated paper tape. Each time the
CNC read one
character, the PC would supply the next one.
> [Can you recommend a DNC program to do this? At this point, I'm notYes, many of the old controls requires part programs to be called by
> sure
> the CNC control that's on the machine is capable of asking for
> programs by
> name- there seem to be mostly numbers on its keypad, with only a few
> letters, like "G" and "M". Could I call a program by a numerical
> "name",
> like "123" ? Anyway, thanks for the help, I really appreciate it. As
> you
> can probably tell, I'm fumbling around in the dark here, although
> there
> seems to be some light at the end of the tunnel...]
number.
If you don't have at least operator manuals for the Centurion, forget
DNC, because
you'll never get it working without those manuals. I can't recommend
any DNC
programs, as I only know they exist, but have never used one. The most
important
detail is that they support your Centurion control. Since I didn't have
DNC hardware
or software for my CNC, I went with the paper tape reader interface.
Jon