TVM program for HP20S



#2

I wonder if someone out there has a TVM program for the 20S. My wife needs those functions but she refuses to use any thing RPN or RPL.
Thank you.


#3

You can probably program in a simple payment program, but with only 99 steps and NO SOLVER, you might not get a nice TVM program like the 12c or other Hp's.

The Hp21s has TVM via a loadable program (and I do have that out of storage). If it works well, and I can look at, I will post code so you can use on 20s (should work key for key).

But a far better and more reliable way to handle might be to buy an Hp10B (not the Bii, in this case).

Another approach is to buy an Hp38G and use its solver (Hp38G has nice HP quality keyboard). Or buy an Hp17B (cheaper than an Hp17Bii since it is NOT RPN selectable). Also Hp18C's sell fairly cheap (looks just like a 19B, but with a lot less RAM and no Trig)

If you can find it or get very lucky, an Hp27s is the calculator of choice (but you could get an Hp17Bii or Hp19Bii for less). An Hp22s also has TVM in a built in library, I believe.

If she doesn't mind colorful and rubber keys, an Hp49G has TVM and can be set to algebraic. Hp39G's are dirt cheap and behave just like the Hp38G's (aside from rubber keys) and give you access to lots more features ie RAM, programs, and other goodies.

Lastly, if you can bear it, a Ti-83 (graphics) or a BAII plus would work nicely. Both are actually pretty good, I just am Highly biased myself to Hp calculators.

Cheap and Fast solution: Buy an Hp10B. Simple easy to use calculator.

Best solution: Hp27s but $$$$ and hard to find.

I also like the Hp19BII+, but I can't say anything about the keys (I haven't touched one).


#4

my votes-

the 20s is going to be rought to solve for, but you cna maybe do it.

the 10b (not ii) is great, and makes a matching pair with the 20s if she needs to do 'other math stuff' ever.

the 17Bii and 19Bii are probably the best, hands down- anytime you are dealing with finance you will have to deal with lists, equations (solver), and statistics. (and the 17Bii+ has a lot more RAM)


the 38G is really cheap, though :)

let me see how short any kind of usable tvm progrma can be....

#5

Hi Chan,

I programmed it in once, but in a very simple way:


I just translated the equation into the program space, but you have to know what you want to solve for, first--and arrange the equation to isolate the chosen variable. I am not sure if the 99 lines is enough so that you could have 4 different routines: for P, int, N and B (assuming no FV or initial value variation).


Regards,


Bill


#6

Thanks RR and Bill for the responses. I think I can get something working here but more suggestion would be greatly appreciated.
Let me explain a bit about my situation here. My wife as in my original post won't use any RPN or RPL machine. She also won't let me make any purchase as she knows that I love to buy calculator stuff.
For the calculators in my collection they are:
HP20S
HP32SII
HP41CV and 41CX
HP48SX and 48GX
HP97
TI58C
TI55
TI85

Now I am pretty sure that the TI85 can run some nice TVM program but I am not familiar with the thing and downloading software is not possible because I don't have the link cable. (buying the link cable is not an option).
I am familiar with the TI58C so may be it's an option but since this is an HP forum I didn't want to post such a question.
The HP20S is about the only other alternative.

Again thanks for any suggestion.


#7

Kind ok clumsy but it works.

http://www.hpmuseum.org/software/20stvm.htm

#8

Hi Chan,

Your other option is to let her use the 32sii----you put the TVM equation into the equation list, and you can solve for any variable.

Or, if you are doing the 20s route, just translate:

Most likely, you want to find out hte payments, given a set initial balance and a fixed interest rate and number of payments. So:

Given that

-B = P*[1-(1+I/100)^-N/(I/100) ] + F*[1+(I/100)]^-N

It is a simple matter to program your 20S to solve for -B: Just STO the appropriate values for payment ,interest, and number of payments, and then run a program that does this equation:

LBL A
RCL P
*
(
1
-
(
1
+
RCL I
/
100
)
y^x
RCL N
+/-
)
/
(
RCL I
/
100
)
=
+
RCL F
*
(
1
+
(
RCL I
/
100
)
)
y^x
RCL N
+/-
=
RTN

for the variables, use 0 for P, 1 for I, 2 for N, and 3 for F

If you enter exactly what is here, it will run fine.

Example, a 5 year used car loan at 4.8% APR, with 100 per month, and no value at end of the loan:

-B = $5324.89

so, first you store 100 in register 0, 0.4 in register 1 (that is, 4.8 / 12) and 60 in register 2, and 0 in register 3.

If you want to solve for P, you have to rearrange the equation and reenter it in the calculator. If you are lucky, it will fit along with this program, just as "label B".

There are 47 lines, and the checksum (assuming no other programs in memory) is 8A8b (leftshift show ["."] in program mode)

BTW, I entered this equation after writing it straight down, and ran it, and it worked fine. The 20S is a fine little simple algebraic machine!

Best regards,

Bill Platt


Edited: 4 Sept 2003, 2:29 p.m.


#9

OK, so here is the equation rearranged equation, solving for "P" (payment)


We assume that the operator can handle the -B business in the front end, so there is no +/- call. You can also save lines in both these routines if you make sure to enter the "N" as a negative number (then you can remove those +/- lines as wll).

Given: P = -B-F*(1+I/100) / { [ 1-(1+I/100)^-N] / (I/100) }

B = register 4,
F = register 3,
N is Register 2, I is register 1

LBL B
RCL B (assumes -B is stored in B)
-
RCL F
*
(
1
+
RCL I
/
100
)
y^x
RCL N
+/- (don't need this if N is saved as negative)
=
/
(
(
1
-
(
1
+
I
/
100
)
y^x
RCL N
+/- (dont need this if N is saved as negative)
)
/
(
RCL I
/
100
=
RTN

I have not attempted to totally optimise this--saving a few lines where possible. But both porgrams fit!

Best regards,


Bill

#10

Sounds like the rest of us. I buy anyway, but have to wear earplugs on many occasions. Your Ti-58C is a poor substitute even if you have the finance module (but then agaaaain, you might make another Hp convert). But then I shouldn't need to tell you, since you do have one.

The Ti-85 does have some software available via download (I know, not an option) and it also has a simple solver that can easily handle the TVM eq. It is your best bet without shelling out any bucks under your constraints. It is superior to an Hp20s for versatility (quality and feel are a different matter). This was Ti's answer to the Hp48G (didn't quite measure up, but got them in the game). If you no longer have manual, Ti website either has or you could probably use an 86 manual for reference which is definitely available via download from Ti.

If the wife gets tired of carrying around a graphics, then suggest a $20-30 pocket calculator such as the Hp10b or the BAII+. I suggest the BAII+ for versatility, but the Hp10B is still a quality calculator (unlike the more recent 10Bii trash, I haven't played with the latest and very newest of course).

Good luck!


#11

I have to agree with what Ron and some of the other folks have mentioned: sneak off and buy a dirt-cheap 10B! I bought one years ago for my wife, who also is RPN-challenged. She recently decided to get a "fresh" Casio or some other non-HP unit, so I sold the 10B for peanuts on eBay. They are nice, solid business calculators with decent keys.

#12

I say take away her algebraic calcs!! ;-)


#13

I say, TAKE AWAY ALL OF THEM! (Except for a museum collection, of course).

(sigh)

#14

Hi...

I hate to say this - in this HP forum but the TI-58C has all the financial formulas built-in in the Master Library ROM, which was included with each and every 58/59 calc.
I still have mine and also the manuals, if you need info on how to use it I will be glad to help.

This is, if you must use the TI, the LED and rechargeable batteries may not be the way you want to go.

Regards;

Roberto


#15

Roberto!
Yes I need info to use the library. I have the module installed in the calculator but I lost the instructions for the module. It would be great if you can help. I would like to use other programs in the library too.
Thanks

#16

There's a kind of cable that you can make for it, that requires no electrical parts (just cable and ends). Check google

and programming it may not be that hard- I am fairly certain the manuals can be downloaded...


#17

Thanks Gordon,
I looked at a few drawings for the cable and they don't look that difficult. They do requires some resitors and diodes but that's not a problem. The connectors used are readily available unlike the one on the 48 and 49.


#18

the manual:


http://education.ti.com/us/product/tech/85/guide/guides.html

cable plans (there are more on the web)

http://www.ticalc.org/hardware/cables/index.html

-C

#19

You can buy a HP-10B cheaply!


#20

Thanks for all the good suggestions and assitance. This is what I did.
I wrote a simple program that would only calculate the payment based on interest rate, number of payments and present value. It basically what my wife needs.
I got the instructions to use the master library for the TI58C. I can get the TI58 to work but not the 58C but it's not a problem. Thanks.
I will be making the link cable for the TI85 and look for some program to download. Thanks again for the info.

So look like I am OK.

Thanks.


#21

I did get my 21s out and load the TVM program. It takes ALL 99 steps, is in keyboard code and would have taken me a while to re-code to standard label keystrokes for the 20s. I could easily SCREW this up and my 20s's are still in storage, so I had no way to check if my translation was successful.

I still suggest an HP10b, if your wife complains about the large graphics calculator.


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