The Museum of HP Calculators

HP Forum Archive 04

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HP 28
Message #1 Posted by Juan J on 28 Nov 2000, 6:58 p.m.

I just bought an HP-28S. A scaled-down 48 in many respects, I think. But I'm starting to like this puppy.

I installed time and compression software, which works well. I also got curve fitting software. Does anyone have a polynomial evaluation/root finding program? I just don't have enough time to write the stuff.

On the other hand, is it possible to assign functions to keys? The manual says nothing about it, and I'm just curious.

      
Re: HP 28
Message #2 Posted by Andrés C. Rodríguez (Argentina) on 29 Nov 2000, 7:15 a.m.,
in response to message #1 by Juan J

I am not very familiar with the HP 28, but the built in Solver should be enough for most "root finding" situations. And you have also a Plot function that will help to graphically find the roots or estimates.

As for polynomial evaluation, simple programming may do; and you even have some symbolic math capabilities built in your HP28 !

            
Re: HP 28
Message #3 Posted by Juan-J on 30 Nov 2000, 1:31 p.m.,
in response to message #2 by Andrés C. Rodríguez (Argentina)

First of all, thanks, Andres. I became too accustomed to the HP-41 Math Pac Polynomial Evaluation software and the corresponding solver on the 48GX that I always like to have one installed on the machines I use. In the end I modified a 48SX program, and that made it.

Since there has been nothing about assigning keys, I assume that cannot be done.

                  
Re: HP 28
Message #4 Posted by Andrés C. Rodríguez (Argentina) on 30 Nov 2000, 1:48 p.m.,
in response to message #3 by Juan-J

As I said, I am not much familiar with the HP 28, I assume it should be possible to assign program labels or functions to the top row of keys ("softkeys") under the display, in a similar way as the CUSTOM menu of the HP 42S, which I do know well. So my answer is a flat Don't Know; it is not a Yes nor a No. You may check the functionality tables of each model here at the Museum.

                  
Re: HP 28
Message #5 Posted by Erwin on 1 Dec 2000, 3:47 a.m.,
in response to message #3 by Juan-J

Hello Juan,

Except for the user and custum menu's there is no way of assigning key's. There is no user keyboard like you have on the 41C or 48

Lots of pleasure with your 28S,

                        
Re: HP 28
Message #6 Posted by Juan-J on 1 Dec 2000, 7:40 p.m.,
in response to message #5 by Erwin

Erwin:

Thanks. As I wrote, I'm starting to like this puppy. Some people even take it for a 19, and it's funny to see their faces when they see a slightly different keyboard layout and a red shift key.

On another subject, thankfully, I got time software. As a former 41CX/48 user, I feel kinda "incomplete" without a watch. Which has to do with lab assignments back when I was in the university. I even wonder sometimes why HP did not include a stopwatch in their Saturn-powered calculators.

      
Re: HP 28
Message #7 Posted by Dan on 7 Dec 2000, 11:13 a.m.,
in response to message #1 by Juan J

In your last post, you state that you were a 'former' 48 user. Why would you use an HP 28 over an HP 48xx series calculator? I have a 28S and am getting a 48GX from Santa. :) Just curious.

            
Re: HP 28
Message #8 Posted by Ron Ross on 7 Dec 2000, 9:40 p.m.,
in response to message #7 by Dan

I have both and I prefer the 48 over the 28 but that is my opinion. I like the ability to download software vs. keying in programs also.

            
Re: HP 28
Message #9 Posted by Juan J on 11 Dec 2000, 11:38 p.m.,
in response to message #7 by Dan

Hello.

What I meant with "former" was that both the 41CX and the 48GX were the calculators I had used and known most before becoming a collector.

A while ago I got a 48SX and a 32S, started a little collection. Turns out that some functions in both 48 models were "provided for compatibility with the HP 28", so I became interested in what I call the 48 series technology demonstrator, the HP 28.

I finally bought one a month ago, and I am learning about it. My interest in this puppy is from a collector's standpoint, which does not mean I don't use it for serious number crunching every now and then (although I prefer the 41CX for that.)

If you are going to get a 48GX for Christmas, just do it. It is a fine machine with a lot of power and, from what I've seen of the 49, that well known HP feel. I bought mine a year before I graduated and have done a lot with it, including field use and some torture testing. Plug-in cards, PC-downloadable software and IR are just some of the good features of this machine; built-in functions and programming are excellent too.

If only HP could keep on making such good stuff...


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