HP 30b Business Professional User manual

The HP 30b Business Professional
Gene Wright
What is it? The HP 30b is Hewlett Packard’s new mid-range financial calculator. This
machine is a very welcome addition to HP’s financial calculator line. The HP 30b comes
with a very small printed manual, which certainly seems to be the continuing trend. A
larger PDF manual is available online as well as 40 learning modules that go into greater
detail on how to use the HP 30b. This review will focus on the new features found on the
HP 30b and differences between it and the HP 20b.
Physical differences. First off, the HP 30b uses rotate and click keys. This is a welcome
improvement over the HP 20b keys, which many found to be inadequate. While the
author never had any real problems with the HP 20b keys, it certainly is nice to have a
good click when pressing a key. Secondly, the HP 30b comes with a metallic-looking
faceplate compared to the shiny black faceplate on the HP 20b. The accompanying
picture on the HPCC website does not quite do the real color justice – the real calculator
color is more bronze/copper than pure silver as the picture would suggest. The back of
the HP 30b is the same black plastic as on the HP 20b. The HP 30b comes with a slip
case to protect it.

Bond calculations. The HP 30b includes two bond duration calculations – the modified
duration and Macaulay duration. These measure a bond’s price sensitivity to fluctuations
in interest rate movements by giving what is essentially a time value of money weighted
average time to maturity. While the modified duration has been in other manufacturer’s
calculators before, this may be the first time the Macaulay duration has ever been on a
preprogrammed calculator.
MIRR and FMRR. The HP 30b extends the usefulness of the HP 20b’s cash flow
analysis tools by including Modified Internal Rate of Return and, for the first time ever in
a financial calculator, the Financial Management Rate of Return. Both of these tools
address a problem with the basic IRR that occurs when the signs of cash flows switch
from negative to positive to negative, etc. – there can be multiple interest rates that make
the present value of the cash flows equal to the cost, which is the definition of the IRR.
That’s a particular problem if you’re trying to use IRR to make a decision. MIRR and
FMRR provide one rate of return that more accurately reflects the return an investor
receives. They differ on how they manipulate any negative cash flows after the initial
cash outlay.
Black-Scholes. The HP 30b includes a menu that computes put and call option prices for
European options using the Black-Scholes method. While Tony Hutchins provided the
programs to compute these for the presently shipping HP 12c calculator manual, this is
the first preprogrammed financial calculator from HP to have this built-in. This menu is
invoked using the shift+hold method and is labeled on the keyboard above the BOND
key.
Canadian Mortgages. A new Mode menu setting allows the choice of TVM Standard or
TVM Canada. When TVM Canada is chosen, the compounding periods per year can be a
different value from the payments per year. Canada is the name given since Canadian
mortgages compound interest semiannually while having monthly payments, but any
combination of compounding and payment frequencies per year can be specified.
Other. The Probability sub-menu in the Math menu has been extended by including the
binomial probability distribution. There is also a choice in the Stats menu for frequency
statistics, which is quite useful for analysis of grouped data. The Math menu has two new
functions: IP for integer part and FP for fractional part.
Still missing? In the earlier HP 20b review, several
things were listed as missing. Of these, the shift key
position being more centrally located and the lack of
a primary key for storing numbers remain on the
wish list.
Found? Programming. Yes, that’s correct. The HP
30b contains programming abilities that are a
mixture of several things: key recording macros,
RPN and RPL too. Programming commands are
mapped to the shift-hold positions of the top 4 rows
of keys. These commands are not printed on the
faceplate and will not execute in run mode, but only
in program editing mode. To help the user who

wants to write programs more easily remember the command locations, a clear, thin,
sticky overlay is provided which lays over the top four rows of keys.
The program catalog is entered by pressing shift and then the close parenthesis key.
There are 10 program slots available in the program catalog (Prgm 0 through 9) and 290
bytes of programming space available on the machine. Note however that program
memory cannot be backed up to any external device. Programs can be assigned to
primary keys, shifted keys and shift-hold key positions. Six conditionals are present
comparing two values. Each comparison pushes a 1 if true or 0 if false to the stack.
Conditional transfers are goto if true (displayed as GT in a program but GOTOT on the
keyboard overlay) and goto if false (displayed as GF in a program, but GOTOF on the
keyboard overlay), but note that these conditionals consume the argument on the stack. A
quick test for x=0? and a branch to a label if true is (of all things) merely to place a GF
XY instruction in a program and if the value in X is equal to zero, a branch to label XY
will occur. This works because a zero is a false argument and GF will branch to the
indicated label if the display contains a zero. An unconditional goto is also provided.
Destinations for these gotos are any of 100 global numeric labels, 00 through 99. Four
levels of subroutines are available using the CALL and RTN commands. Values can be
displayed while a program is running using the DISP command. Even a short prompt of
letters can be displayed using the MSG command. This has been put to good use to make
a “high – low” number guessing game more fun.
If viewed as primarily a “macro recording” ability then some of the operating
characteristics of HP 30b programming will make more sense. For example, to access the
inverse sine function in the Math menu, the program steps will look like this:
:sI<=, which will take four program steps, take four bytes and show as
Math Input Down = on four lines in the program listing. Each keypress required to
navigate through a menu is recorded as a separate step and uses a byte. Some commands
are merged and shown as one step, however, such as store, recall, and gotos.
For what are 290 bytes good? More than you might think. It is very easy to use these
abilities to bring functions buried in menus out to the keyboard for much easier access. If
you find yourself needing access to the inverse trig functions, short programs can pull
them out of the Math menu and be assigned to the shift-hold locations for sine, cosine
and tangent. If you find the need to use the built-in probability distributions, they can be
brought out of the Math menu and assigned to keys. This is a great time saver. Short
programs have also been written for things such as a prime factor finder, a translation of
the HP 25 lunar lander game, base conversions for bases 2-10 and more.
Found? HP Solve. The solver is accessible by first writing a program that evaluates an
equation such that it would equal zero, using memory registers to represent variables in
the equation. For example, an equation of X – Y = Z would be rewritten as X – Y – Z = 0
and entered as a program like this: RCL 1 RCL 2 – RCL 3 – RTN. Memory 1 would
represent X, memory 2 represents Y and memory 3 represents Z. Store values into
memories 2 and 3 and SOLVE 1 will find the value of memory 1 that makes the equation
equal to zero. This forms the basis for the generalized odd days loan solver program
found in the HP Solve examples learning module. This program includes conditional tests
and branching and is an indication of the usefulness of the included HP Solve
functionality.

What are some other goodies included? The mode menu settings can now be stored
and recalled by pressing store or recall and then :u. This key sequence brings up a
12 digit number with each position corresponding to a mode menu item and its setting.
The two rightmost digits for example control the number of decimals displayed. Pressing
4:$:u in run mode or in a program will change the number of decimals
displayed to four regardless of the original value. Pressing 314:$:u
will change the operating mode to RPN and since 14 is an invalid value for the number of
decimal digits displayed, will not change the display setting. This is described and a table
of these values shown in the Programming Reference learning module.
The 100 memory locations used to store up to 50 pairs of statistics or cash flow data can
be addressed indirectly using a location stored in memory 0. If 5 is stored in memory 0,
the key sequence :$:y will store the value in X into the 6th position of the
statistics data area, since it is addressed starting with position 0. This allows for the use of
a rather large data set and has already been used to compute and store nearly 700 digits of
PI on the HP 30b as shown in the Programming Examples learning module.
And, of course, all the existing scientific functions (and other financial functions) are still
present in the HP 30b.
Conclusion. This is a good financial machine that addresses many wish-list items left
unfulfilled from the HP 20b. In many ways, this is the most powerful financial calculator
HP has ever made. It is certain to give fits to the financial calculator designers at a certain
company near Dallas, since there are a large number of empty spaces next to their models
on any comparison chart. Now, HP, we’re all still hoping (and waiting) for a new low-
end scientific model …