1 Sep
1999
1 Sep
'99
2:01 p.m.
At 09:00 AM 9/1/99 -0600, Dick wrote:
My plotter, admittedly not exactly identical, but VERY
similar, requires
that you load the paper, press the button that says "chart hold" or some
such, then, after allowing the plotter to look for the edges of the paper
(an important step because it initializes the origin to the center of the
paper), press "on-line" at which time the DTR light becomes really
important. Now, the plotter will work from a null-modem arrangement if you
use X-on/x-off but I've had my best luck with the cable hooked up
differently. I'd go into detail, but that was with the old v3.22 OrCad
drafting utility and it had to have a specially wired cable to work
correctly.
I've also opened the box and socketed and replaced the components on the
little serial interface board, which uses a Z-80 Dart and some 1488 and 1489
drivers and receivers. If this little comm interface module isn't happy,
the whole plotter knows about it and doesn't work well.
Back in the late '80's, when I got mine, the HP support for these (they were
still selling them) was terrible. No one really knew what was necessary to
make them work.
I know. AFTER you bought it you found out that you needed all kinds of
optional I/O ROMs and the like to make it work.
Nowadays, there's nobody there who'll even
talk about them.
Yeap.
If you want to test the thing thoroughly, you'll have to get some of the
toilet paper that fits it, (mine only uses cut forms) making sure you still
have the cutoff blade located in the little groove at the front and then
load the paper in the paper path (straighforward, assume the obvious) and
then send it various drawings which use different size paper in different
orientation.
Sounds like a HP 7221 plotter with paper feed. I have one of them and a
9874 that's similar but has a HP-IB inteface. Someone dropped the 9874 on
one corner and bent the whole thing out of kilter. I've tried everything
but I can't get it to feed paper right. The framne is too heavy to try and
straighten out. Perhaps if I took it to someone that has a puller for
straightening car frames .....
These machines will feed the appropriate amount, but don't
mind wasting paper, i.e. they feed the 36"-wide
paper 14-15" for a portrait
'A'-size form, wasting most of the paper. That was the reason I got the
single-sheet version. I don't need it to run all night unattended, but I do
have to pay for the paper. You'll see that's not cheap.
I always use mine if single sheet mode. BTW any idea where I can find a
roll of paper for it? I only have a small amount of paper left and I'd
like to have a roll to go with it.
That may explain
why the drawings in most manuals are so difficult to
read, having been
reduced from already-too-small drawings.
The manuals may still be available somewhere, but I would get right on
trying to find them if I were you.
I have a PRETTY GOOD bunch of plotter manuals. In fact, I have a good
bunch of all of the HP computer and calculator manuals. I grab everyone
that I can get my hands on! What model plotter do you have?
I made the purchase of my plotter
contingent on complete manuals, so they were included.
That became a
condition after I found that Martin Marietta, after buying 20 or so of these
still hadn't received a complete set of manuals even though each plotter was
supposed to come with them.
Boy! Does this bring back memories! When I was working in Canada for
Martin Marietta we could never got any of the drawings and other documents
from MM in the US. I keep calling and they kept telling
me that they had
been sent. In fact some of them were sent three times with multiple
copies
everytime. I finally got the name of the guy that they were sent to in
Canada and I went found him. It turns out that he kept one copy of
EVERYTHING that went through his office. I checked the next office that
handled the stuff and they did the same thing. So did the next office. And
the one after that! As it turns out the handling people kept everything and
the ones of us in engineering never got the stuff that was supposed to be
coming to us. I think that was SOP for MM!
If you have access to a Windows box with AutoCad 12 on it (I don't have a
later version to try this) you should be able to put it through its paces,
as that has an internal plotter driver which operates independently of the
one in WIndows. I've had no luck at all getting the Windows driver to do
anything. I suspect (after watching the lights on the breakout box) that
there is some incompatibility in the way they work their handshaking.
Perhaps the '488 port will work for you, if you've got one with drivers in
your system.
Well I'm using a HP 7550 on the PC so it may be more compatible than
your older model. But I think you need more than a null MODEM cable to make
the plotter work. I have a manual with the cabling schematics somewhere
and I think the HP requires more of the pins to be connected than most
serial devices do. I'll look for the cabling drawings if you want them.
Joe