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.

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.

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.

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

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.

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

1/x

nPr

nCr

Pol (x, y)

Rec

(r,

)

Internal

digits

15 digits

Accuracy

As a rule,

accuracy is

±1 at the

10th digit.

Notes

However, for tanx:

|x|

90(2n+1):DEG

|x|

π/2(2n+1):RAD

|x|

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

|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) |

| < 9 ×109°

(RAD) |

| < 5 ×107πrad

(GRA) |

| < 1 ×1010grad

Appendix D Input Ranges

177

Appendix

However, for tan

90(2n+1):DEG

π/2(2n+1):RAD

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

–1 ×10100 < logy< 100

y= 0 : x > 0

y< 0 : x = 2n+1,

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

n, y

n, x, y, a,b,c, r :n

n–1, y

n–1: n

0, 1

178

Appendix

–––––

2n+1

––

Function

°’ ”

←

°’ ”

^(xy)

ab/c

STAT

*Errors may be cumulative with internal continuous calculations such as ^ (xy), xy, x!, 3x, some-

times affecting accuracy.

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