7470A Plotter Purchasing Assistance Required



#27

I think I need a 7470A Plotter. I've noticed that they come in 3 different flavors: Serial/RS-232, HP-IB, and HP-IL.

Questions:

  1. HP-IL models are rare, very rare, I've never seen one for sale. Since I want to use with my 41 and 71, can I use a HP-IL to Serial Interface (82164A) or a HP-IL to HP-IB Interface? I own the former, so that would be better. Has any done the former? I'd also prefer the former so that I can test PC-based 7470A emulators. NOTE: I have scanned the archives and a post indicated that using the 82164A would not work, but I thought I'd ask just in case.
  2. Replacement pens suggestions.
  3. Any thing I should look for ask when getting a used plotter? Never owned or used (or seen) one.
Thanks.

#28

Quote:
NOTE: I have scanned the archives and a post indicated that using the 82164A would not work, but I thought I'd ask just in case.
I haven't tried it, but I can't think of any reason it wouldn't work, except that I have a 41cx with the XIO module integrated with the HPIL module, so I tend to forget which functions might not be there if you only had for example a 41cv with HPIL and no XIO or XFCN module. I have the plotter manual and the plotter language is pretty easy.
#29

Quote:
I think I need a 7470A Plotter.

Do you really "need" it, or want it?

I had one 20 years ago, and basically got rid of it when/because computer graphics and color printers far surpassed its capabilities. So, if you need to do computer graphics, there are other better ways.

Of course, if you want to play with it for old time's sake, which I suspect it the case, then go for it. In fact, just two days ago, I pulled out of a drawer an RS-232 adapter that I made for it. I think it is basically a pin 2/3 swapper. If you want/need it, I'd be glad to send it to you.

I got mine from an electronic leasing firm (it may have been Leasametric). I have seen them for sale in the last year or two from such outfits, but the prices were outrageous. The advantage of buying from such a firm, though, is that it will come in working condition, they will almost certainly warrant it for some time period, and it probably will come with a manual, whereas on e**y you never quite know. I'd ask any e**y sellers to show you a plot they have made recently.


#30

Quote:
I had one 20 years ago, and basically got rid of it when/because computer graphics and color printers far surpassed its capabilities.
They definitely do not surpass a pen plotter in ease of programming though, and there will always be applications where the colors and typset-looking 2-point characters that a modern printer can do are of no value. There will always be that odd lab job for which there's no commercial software available but you could write your own HP-41 program for it in an hour, including graphing results on a pen plotter.
#31

Quote:
Do you really "need" it, or want it?

I "want" to create a 7470A emulator for Nonpareil, so I think I'll "need" one to do a proper job.
#32

Buy one with an HP-IB interface, they are not so hard to find as those with HP-IL interface. Together with an HP-IL -> HP-IB interface they work fine. For the 41 you can use a plotter ROM, for the 71 you can directly send the appropriate plotter commands. Be warned: with the 41 plotting is sloooow; it's so slow that it's not too much fun. The 71 is faster, but I would suggest using a 75. Pens are not a problem; replacement pens are available at eBay or from Internet shops, Google will help you.
I did some drawings with the HP-85 and an 9872B, and my daughter (and of course me, too) was fascinated when she saw the pen moving around and drawing a nice rose curve. There are other calculators/pocket computers with plotters like the Sharp PC-1600 or the Casio PB-700. Not the good HP quality but nevertheless interesting and a lot of fun.

Best Regards from Switzerland,

Juergen

#33

llo Egan:

While I cannot help you with your interface issues, I own and use several different types of HP plotters via RS232 interface on my HP48. Email me for details if you like.
Regards,
TomC

#34

Egan,

If you try a serial version of the 7470A with the 82164A interface, please let us know how it works. I have been looking for an HP-IL 7470A for awhile, but they are very difficult to find. I bet many of them have ended up in the trash when someone looks at the interface jacks and thinks "What is this? It can't interface to anything I know of." I found one about 10 years ago, but did not want to pay the price at the time.

Dan


#35

According to this it is not possible: http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv013.cgi?read=36100. I hope someone has actually tested to determine a definite yes or no.


#36

Quote:
According to this it is not possible: http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv013.cgi?read=36100. I hope someone has actually tested to determine a definite yes or no.
That seems to refer only to printing bar code with it; but in the other thread referenced there, Emmanuel in Normandy, France says he has done it.
#37

BTW - if one has to go via HP-IB, any reason one should not go for the 7475 which has 6 pens? Can the 41 address all siz pens or only 2 pens? And the 71? They both seem to be equally hard to find...

Cheers

Peter


#38

There's no reason you can't form the instructions to use more pens with the 41. Use the "SPx" ("select pen") instruction where "x" is the pen number. HPGL instructions are just text, with semicolons separating the instructions. If you can form and output text over the appropriate interface (HPIB, RS-232, etc.), you can feed the plotter. With a 41, you would form each instruction and send it with ACA. I have the manual in front of me. The plotter has quite a rich instruction set. Each instruction is two characters (like "PU" for "pen up") followed by one or more parameters when appropriate.

Besides the number of pens, another difference with the 7475 is that it can handle 11x17" paper, not just 8.5x11"

Edited: 17 Mar 2009, 2:47 a.m.


#39

Thanks Garth!

#40

One more question - I just spoke with a vendor of used 7470a's and 7475a's and he said the the true problem is to calibrate the plotters. For which one needs a calibration sheet from HP which they sell for the bargain price of $700. I searched the forum but could not find anything about this here. Any one has any experience in this?

Cheers

Peter


#41

We used a 7475 at my last place of work to plot PC boards (back when we had to plot them ourselves instead of just Emailing files to the PC board manufacturers), and we were always amazed at how extremely accurate the 7475 was. As I remember, it has stepper motors, not servos, and the pen is moved by a notched belt, and the roller that moves the paper has something like carbide particles on it, so it won't wear down. I would say calibration is a non-issue. It's not an analog X-Y plotter.

Edited: 18 Mar 2009, 5:07 p.m.


#42

Thanks Garth, you are a well of information! I think I'll give it a shot. Prices for 7470a and 7475a are almost the same so might as well go for 6 pens :-)

One last question, I did not find a place online with the manuals for the 7475a, do you know of a place? Or can I use the 7470 for starters?

Cheers

Peter


#43

Quote:
One last question, I did not find a place online with the manuals for the 7475a, do you know of a place? Or can I use the 7470 for starters?
I don't know where to get one. The graphics language (HPGL) would be the same, although there might be limitations on one unit, for example not being able to select pen 5 if it only has two, or going for an X-Y coordinate that does not exist on the smaller paper.
#44

I used an HP plotter way back in my undergraduate days in engineering school 25 years ago. The precision those instruments provided was amazing to me. I was not involved in their calibration, but I would assume that the cost of the calibration sheet or fixture was related to the precision and linearity requirements for the plotter output. The specs were likely very stringent, but would not be required for anything but the most demanding applications.

Besides some basic data plots of the tested physical properties of materials, I also used the plotter to make custom Christmas cards! They were very unique! Although I doubt I was testing the limits of precision or linearity with either of my applications.

By the way, does this vendor of used 7470A's have any Opt. 3's available?

Dan


#45

Dan,

Good to hear from you.

I have never found an opt3 anywhere so far... Would love to, but no luck so far.

So this means I have to go via HP-IB anywhere which is why I thought why not use 6pens instead of 2. They both are about $110 inkl of shipping but I'm hoping to find something cheaper. Problem is that shipping is normally very expensive...

Cheers

Peter


#46

Just joined today and caught this message thread.

Years ago I attended a talk given by an HP engineer that said that the rollers actually imprinted the paper with small indentations that effectively registered the paper with the plotter so that alignment is maintained extremely accurately. Such that even they were impressed with their achievement.

Reading my HP-41 Plotter Module Manual, though it gives examples with the 7470, it states that it will work with any HPGL device. When you initialize the plotter module it will read the X-Y limits (in mm) from the plotter. And the plotter determines what pen it uses when you do a pen select, the 7470 uses the left pen for any odd value and the right pen for any even value, so it should work just fine with the 7475.

(I have a 7470A with HP-IB and drive it from my HP-41 using a HP-IL/HP-IB interface)


#47

Thanks John for the information, much appreciated!

Cheers

Peter

#48

Hallelujah! I think I got one. I've got a tracking number, I'll let you know what shows up in the mail.

Dan


#49

awesome! HP-IL or HP-IB?


#50

HP-IB seem to be quite common.

No, I have snagged an HP-IL version, or so the vender said. "Refurbished with 90 day warranty, and some new pens". Have tracking number, UPS says to expect delivery on Monday.

I've had the HP-41 Plotter module (actually two of the, NOS) and have been dying to try them out. May finally get my chance.

I wasn't even this excited at Christmas time.

Dan

#51

Hooray, Hooray. I am finally the proud owner of a 7470A Opt. 3 Plotter. I received it today, it is in very good condition, and my HP-41CX talked to it nicely. It is a pretty cool peice of gear. I can't wait to dust off the Plotter module and run the equipment through some tricks.

Dan


#52

Awesome Dan, congratulations!

Let us know how it goes!

Cheers

Peter


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