Citizen SRP-320G

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production:   Display type: Graphical display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 5½"×3"×½" Display size: 35×23 pixels and 11+3 characters
Weight: 3 oz    
    Entry method: Formula entry 
Batteries: 1×"CR-2032" Lithium Advanced functions: Trig Exp Hyp Lreg Grph Ab/c Cmem BaseN 
External power:   Memory functions:  
    Programming model: Formula programming 
Precision: 12 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 26 numbers Program display: Formula display  
Program memory: 400 program steps Program editing: Formula entry  
Chipset:   Forensic result: 9.0000296195  

srp320g.jpg (32244 bytes)The Citizen SRP-320G is a graphing calculator. Looks nice and unique, but upon closer examination you may find that it is not really unique and not as nice as you might expect. You see, this machine turns out to be no more than an imperfect clone of the Casio fx-6300G. Why imperfect? The Casio fx-6300G didn't have buggy firmware, but that, unfortunately, is the case with the SRP-320G. One of the first things I try on a new calculator is Mike Sebastian's calculator forensics algorithm; on a formula entry model like the SRP-320G, I'd enter sin-1 cos-1 tan-1 tan cos sin 9-9 to compute the result. Except that it computed the wrong result. Closer examination revealed that the calculator executed the last sin-1 operation in Radians mode despite the fact that it was in Degrees mode. I was able to get the correct result when I broke up my expression into two lines: cos-1 tan-1 tan cos sin 9 followed by sin-1 Ans-9. Very sloppy indeed.

Equally sloppy is the manual. At first, my heart was filled with joy: finally, a calculator with a decent-sized manual! It sure is a thick book, reminiscent of the manuals you got with early HP calculators. But when I looked more closely, I found the reason on the title page:


Scientific Calculator


Instruction Manual


Manuale di istruzioni

Manual de instrucciones

Manual de instruçőnes

Рук оводство по эксплуатации

Mode d'emploi

It's easy to make a brick out of a manual if you publish it in seven languages.

By the way, the typos aren't mine. I know how to spell Bedienungsanleitung. And it gets worse. Inside the manual, mathematical expressions are often unreadable. Keyboard symbols and graphics overlap text. The only good thing I can say about the book is that it appears someone ran it through a spell checker: spelling mistakes and grammatical errors that are so common to Far Eastern manuals are missing from this volume. But that is no excuse for the incredibly sloppy, substandard typesetting job!

The program below I wrote originally for a Casio programmable. It runs identically on the SRP-320G. It demonstrates the calculator's capabilities by accurately computing the logarithm of the Gamma function using the Lanczos-approximation. A conditional expression is used to compute the correct result for negative arguments (the machine must be in radians mode):

Abs X→Z:
ln (2.506628275+6.3E-10+(225.5255846+1.9E-8)÷Z-
(Z-.5)ln (Z+4.65)-Z-4.65→G:
X<0⇒ln (-π÷X÷sin πX)-G→G:G