Casio fx-7400G Technical document

Appendix
Appendix A Resetting the Calculator
Appendix B Power Supply
Appendix C Error Message Table
Appendix D Input Ranges
Appendix E 2-byte Code Table
Appendix F Specifications

170
Appendix
Appendix A Resetting the Calculator
Warning!
The procedure described here clears all memory contents. Never perform this op-
eration unless you want to totally clear the memory of the calculator. If you need
the data currently stored in memory, be sure to write it down somewhere before
performing the RESET operation.
uu
uu
uTo reset the calculator
1. Press mto display the main menu.
2. Highlight the MEM icon and press w, or press i.
3. Use cto move the highlighting down to “Reset” and then press w.
4. Press 1(YES) to reset the calculator or 4(NO) to abort the operation without
resetting anything.
• If the display appears to dark or dim after you reset the calculator, adjust contrast.
1234

171
Appendix
Resetting the calculator initializes it to the following settings.
Item Initial Setting
Icon RUN
Angle Unit Rad
Exponent Display Range Norm 1
Fraction Reduction Automatic
Mixed Fraction Display
GraphType Rectangular coordinate (Y=)
Statistical Graph Automatic
Variable Memory Clear
Answer Memory (Ans) Clear
Graphic Display/Text Display Clear
View Window Clear (initialized)
View Window Memory Clear
Graph Function Clear
Enlargement/Reduction Factor Clear (initialized)
Table & Graph Data Clear
List Data Clear
Statistical Calculation/Graph Memory Clear
Program Clear
Input Buffer/AC Replay Clear
• Performing the RESET operation while an internal calculation is being per-
formed will cause all data in memory to be deleted. Make sure that no calcula-
tion be being performed before starting a RESET operation.
• If the calculator stops operating correctly for
some reason, use a thin, pointed object to
press the RESET button on the back of the
calculator. This should make the RESET con-
firmation screen appear on the display. Per-
form the procedure to complete the RESET
operation.
RESET button

172
Appendix
Appendix B Power Supply
This unit is powered by two AAA-size (LR03 (AM4) or R03 (UM-4)) batteries. In addi-
tion, it uses a single CR2032 lithium battery as a back up power supply for the memory.
If the following message appears on the display, immediately stop using the calcula-
tor and replace batteries.
If you try to continue using the calculator, it will automatically switch power off, in
order to protect memory contents. You will not be able to switch power back on until
you replace batteries.
Be sure to replace the main batteries at least once every two years, no matter how
much you use the calculator during that time.
Warning!
If you remove both the main power supply and the memory back up batteries at the
same time, all memory contents will be erased. If you do remove both batteries,
correctly reload them and then perform the reset operation.
The batteries that come installed in this unit when you purchase it are for factory
test purposes, so they will probably not provide normal service life.
kk
kk
kReplacing Batteries
Precautions:
Incorrectly using batteries can cause them to burst or leak, possibly damaging the
interior of the unit. Note the following precautions:
• Be sure that the positive (+) and negative (–) poles of each battery are facing in
the proper directions.
• Never mix batteries of different types.
• Never mix old batteries and new ones.
• Never leave dead batteries in the battery
compartment.
• Remove the batteries if you do not plan to
use the unit for long periods.
• Never try to recharge the batteries sup-
plied with the unit.
• Do not expose batteries to direct heat, let
them become shorted, or try to take them
apart.

173
Appendix
(Should a battery leak, clean out the battery compartment of the unit immedi-
ately, taking care to avoid letting the battery fluid come into direct contact with
your skin.)
Keep batteries out of the reach of small children. If swallowed, consult with a
physician immediately.
uu
uu
uTo replace the main power supply batteries
* Never remove the main power supply and the memory back up batteries from
the unit at the same time.
* Be sure to switch the unit off before replacing batteries. Replacing batteries
with power on will cause data in memory to be deleted.
* Never replace the main power supply battery compartment cover or switch the
calculator on while the main power supply batteries are removed from the cal-
culator or not loaded correctly. Doing so can cause memory data to be deleted
and malfunction of the calculator. If mishandling of batteries causes such prob-
lems, correctly load batteries and then perform the RESET operation to resume
normal operation.
* Be sure to replace all two batteries with new ones.
1. Press !O to turn the calculator off.
2. Push the battery compartment cover on the
back of the calculator in the direction noted in
the illustration and remove it.
3. Remove the two old batteries.
4. Load a new set of two batteries, making sure
that their positive (+) and negative (–) ends
are facing in the proper directions.
5. Replace the battery compartment cover and
pressototurnpower on.Thememory back-
up battery provides power to the memory while
the main batteries are removed, so memory
data is not lost.
• Power will not switch on if you pressowhile
the main power supply battery compartment
cover is open.
• Do not leave the unit without main power sup-
ply batteries loaded for long periods. Doing so
can cause deletion of data stored in memory.
• If the figures on the display appear too light and hard to see after you turn on
power, adjust the contrast.
P.11

174
Appendix
uu
uu
uTo replace the memory back up battery
* Before replacing the memory back up battery, switch on the unit and check to
see if the “Low battery!” message appears on the display. If it does, replace the
main power supply batteries before replacing the back up power supply battery.
* Never remove the main power supply and the memory back up batteries from
the unit at the same time.
* Be sure to switch the unit off before replacing batteries. Replacing batteries with
power on will cause data in memory to be deleted.
* Be sure to replace the back up power supply battery at least once 2 years, re-
gardless of how much you use the unit during that time. Failure to do so can
cause data in memory to be deleted.
1. Press !O to turn the calculator off.
2. Push the battery compartment cover on the
back of the calculator in the direction noted in
the illustration and remove it.
3. Remove screw ion the back of the calcula-
tor, and remove the back up battery holder.
4. Remove the old battery.
5. Wipe off the surfaces of a new battery with a
soft, dry cloth. Load it into the calculator so
that its positive (+) side is facing up.
6. Pressing down on the battery with the battery
holder, replace the screw that secures the
holder in place.
7. Replace the battery compartment cover and
pressoto turn power on. The main battery
provides power to the memory while the back-
up batteries are removed, so memory data is
not lost.
kk
kk
kAbout the Auto Power Off Function
The calculator switches power off automatically if you do not perform any key opera-
tion for about 6 minutes. To restore power, press o.
The calculator automatically turns off it is left for about 60 minutes with a calculation
stopped by an output command (^), which is indicated by the “–Disp–” message on
the display.

175
Meaning
1Calculation formula contains an
error.
2Formula in a program contains
an error.
1Calculation result exceeds
calculation range.
2Calculation is outside the input
range of a function.
3Illogical operation (division by
zero, etc.)
4Poor precision in differential
calculation results.
1No corresponding Lbl nfor
Goto n.
2No program stored in program
area Prog “file name”.
3No corresponding “Next” for
“For”, no corresponding
“LpWhile” for “Do”, or no
corresponding “WhileEnd” for
“While”.
• Nesting of subroutines exceeds
10 levels.
Countermeasure
1Use dor eto display the
point where the error was
generated and correct it.
2Use dor eto display the point
where the error was generated
and then correct the program.
123
Check the input numeric value
and correct it.
When using memories, check
that the numeric values stored
in memories are correct.
4Try using a smaller value for ∆x
(xincrement/decrement).
1Correctly input a Lbl nto corres-
pond to the Goto n, or delete
the Goto nif not required.
2Store a program in program
area Prog “file name”, or delete
the Prog “file name” if not
required.
3Correctly match “Next” with
“For”, “LpWhile” with “Do”, or
“WhileEnd” with “While”.
• Ensure that Prog “file name” is
not used to return from
subroutines to main routine. If
used, delete any unnecessary
Prog “file name”.
• Trace the subroutine jump
destinations and ensure that no
jumps are made back to the
original program area. Ensure
that returns are made correctly.
Appendix C Error Message Table
Message
Syn ERROR
Ma ERROR
Go ERROR
Ne ERROR
175
Appendix

Meaning
• Execution of calculations that
exceed the capacity of the stack
for numeric values or stack for
commands.
1Not enough memory to hold
function input in the Graph
Mode for graph drawing.
2Not enough memory to hold
function input in the TABLE
Mode.
3Not enough memory to store
data in list function.
• Incorrect argument specification
for a command that requires an
argument.
• Illegal dimension used during
list calculations.
Message
Stk ERROR
Mem ERROR
Arg ERROR
Dim ERROR
Countermeasure
• Simplify the formulas to keep
stacks within 10 levels for the
numeric values and 26 levels
for the commands.
• Divide the formula into two or
more parts.
123
• Keep the number of variables
you use for the operation within
the number of variables
currently available.
• Simplify the data you are trying
to store to keep it within the
available memory capacity.
• Delete no longer needed data
to make room for the new data.
Correct the argument.
• Fix n, Sci n: n= integer from 0
through 9.
• Lbl n, Goto n: n= integer from
0 through 9.
• Check list dimension.
176
Appendix

177
Function
sinx
cosx
tanx
sin–1x
cos–1x
tan–1x
logx
Inx
10x
ex
x
x2
1/x
3x
x
!
nPr
nCr
Pol (x, y)
Rec
(r, θ )
Internal
digits
15 digits
"
"
"
"
"
"
"
"
"
Accuracy
As a rule,
accuracy is
±1 at the
10th digit.
"
"
"
"
"
"
"
"
"
Notes
However, for tanx:
|x|
GG
GG
G 90(2n+1):DEG
|x|
GG
GG
G π/2(2n+1):RAD
|x|
GG
GG
G 100(2n+1):GRA
Input ranges
(DEG) |x| < 9 ×109°
(RAD) |x| < 5 ×107πrad
(GRA) |x| < 1 ×1010grad
|x| <1
|x| < 1 ×10100
1 ×10–99 <x< 1 ×10100
–1 ×10100 < x< 100
–1 ×10100
< x<230.2585092
0 <x< 1 ×10100
|x| <1 ×1050
|x| < 1 ×10100, x
GG
GG
G
0
|x| < 1 ×10100
0 <x<69
(xis an integer)
Result < 1 ×10100
n, r(nand rare integers)
0 <r<n,
n< 1 ×1010
< 1 ×10100 x2+ y2
|r| < 1 ×10100
(DEG) | θ | < 9 ×109°
(RAD) | θ | < 5 ×107πrad
(GRA) | θ | < 1 ×1010grad
Appendix D Input Ranges
177
Appendix
However, for tan θ :
| θ |
GG
GG
G 90(2n+1):DEG
| θ |
GG
GG
G π/2(2n+1):RAD
| θ |
GG
GG
G 100(2n+1):GRA

Internal
digits
15 digits
"
"
"
"
Accuracy
As a rule,
accuracy is
±1 at the
10th digit.
"
"
"
"
Notes
Input ranges
|a|, b, c< 1 ×10100
0 <b, c
|x| < 1 ×10100
Sexagesimal display:
|x| < 1 ×107
x> 0:
–1 ×10100 < ylogx< 100
x= 0 : y > 0
x< 0 :
y=n, (nis an integer)
However;
–1 ×10100 < log |x| < 100
y> 0 : x
GG
GG
G 0
–1 ×10100 < logy< 100
y= 0 : x > 0
y< 0 : x = 2n+1,
(n
GG
GG
G 0, nis an integer)
However;
–1 ×10100 < log |y| < 100
Total of integer, numerator
and denominator must be
within 10 digits (includes di-
vision marks).
|x| < 1 ×1050
|y| < 1 ×1050
|n| < 1 ×10100
x σ n, y σ n, x, y, a,b,c, r :n
GG
GG
G 0
x σ n–1, y σ n–1: n
GG
GG
G 0, 1
178
Appendix
1
–––––
2n+1
1
––
x
1
––
y
1
––
n
1
––
x
Function
°’ ”
←
°’ ”
^(xy)
xy
ab/c
STAT
*Errors may be cumulative with internal continuous calculations such as ^ (xy), xy, x!, 3x, some-
times affecting accuracy.