Caretec PLATON XL User manual

User Manual
___________________________________________________________________________________________
Platon XL
Scientific Calculator for
Visually Impaired People

Table of Contents
1: Introduction page 4
1.1: Quick Overview on the Functions of Platon XL page 4
1.2: XL Product Series page 4
2: Description and Scope of Delivery page 5
3: Power Supply page 5
4: Keyboard Layout page 6
4.1: Groups of Keys and Auxiliary Keys page 7
4.1.1: The 4 Auxiliary Keys page 7
4.1.2: 3 x 3 Group (from left to right) page 7
4.1.3: 4 x 4 Group (from left to right) page 8
4.2: Basic Functions page 9
4.2.1: Switch the Device On and Off page 9
4.2.2: Menu Escape Function page 9
4.2.3: Delete Last Digit / Delete All page 9
4.2.4: Keylock page 9
4.2.5: Volume Control page 9
4.2.6: Time and Date page 10
4.2.7: Repeat Function page 10
4.2.8: Backlit Display (option) page 10
4.2.9: Help Mode page 10
5: Calculations page 10
5.1: Standard Arithmetic Functions page 11
5.2: Advanced Arithmetic Functions page 11
5.2.1: Percentages page 11
5.2.2: Square and Raise to Higher Power page 11
5.2.3: Roots page 12
5.2.4: Reciprocal Value page 12
5.2.5: (Pi) page 12
5.2.6: Change Sign page 12
5.3: Scientific Functions page 12
5.3.1: Sinus page 13
5.3.2: Cosine page 13
5.3.3: Tangent page 13
5.3.4: Arcsine page 13
5.3.5: Arccosine page 13
5.3.6: Arctangent page 13
5.3.7: Hyperbolic Sine page 13
5.3.8: Hyperbolic Cosine page 13
5.3.9: Hyperbolic Tangent page 13
5.3.10: Area Hyperbolic Sine page 14
5.3.11: Area Hyperbolic Cosine page 14
5.3.12: Area Hyperbolic Tangent page 14
5.3.13: Natural Logarithm page 14

5.3.14: Common Logarithm page 14
5.3.15: e to the Power of x page 14
5.3.16: 10 to the Power of x page 14
5.4: Conversions page 14
5.4.1: Currency Conversion page 15
5.4.2: Custom Conversion page 15
5.5: Financial Calculator page 15
5.5.1: Compound Interest page 15
5.5.2: Net Present Value page 16
5.5.3: Annuity page 16
5.5.4: Annuity Initial Capital page 16
5.6: Memory Function page 17
5.6.1: Save Values page 17
5.6.2: Select Stored Values page 17
5.6.3: Add Up Additional Values page 17
5.6.4: Delete Stored Values page 17
6: Statistics page 17
6.1: Keyboard Layout in Statistic Mode page 17
6.2: Usage of the Statistic Functions page 18
6.3: Help in Statistic Mode page 19
6.4: Faculty page 19
7: Menu page 20
7.1: Structure of the Menu page 20
7.2: Submenu “Settings” page 21
7.2.1: Volume page 21
7.2.2: Number Announcement Format page 21
7.2.3: Decimal Places page 21
7.2.4: Display Mode page 21
7.2.5: Angular Dimensions page 22
7.2.6: Clock: Setting of Time, Date and Alarm page 22
8: Safety Instructions page 23
9: Cleaning the Device page 23
10: Technical Data page 23
11: Guarantee and Service page 23
12: Disposal page 24
12.1: Disposal of Electronic Devices page 24
12.2: Battery Disposal page 24
13: Manufacturer page 24

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1: Introduction
Platon XL is a scientific calculator with extra large buttons and a huge display with
big digits as well. With the backlit display and the speech output as optional
functions, Platon XL is particularly suitable for visually impaired and blind people.
1.1: Quick Overview on the Functions of Platon XL
Spoken functions with natural voice
Extra large display with 10 digits of 2.5 cm (1 in) height
Extra large buttons, size: 1.5 x 1.5 cm (0.6 x 0.6 in)
Natural and common logarithm
Trigonometric and hyperbolic functions
Arithmetic, geometric, harmonic and root mean square value
Calculations with parenthesis
10 memory spaces
Reciprocal value
Percentages
Square, raise to higher power and extract roots
Calculation of compound interest, cash values and annuities
Conversion of currency and physical units
Date and time with alarm clock function
Volume control in 6 steps
1.2: XL Product Series
XL calculators are available in the following versions:
Non talking, without backlit display
Talking
With backlit display
Talking and with backlit display
Please note that for versions without speech output and without
backlit display not all keys functions are available.
Consult instructions before use! Do not operate Platon XL
without reading the instruction manual. Get acquainted with the
device and all the accessories. Keep the instruction for
reference reading and pass it on with the device.

5
2: Description and Scope of Delivery
Included in the delivery are the scientific calculator Platon XL, a set of batteries (4 x
1.5 V AA) and a printed user manual. A power supply unit and earphones can be
ordered optionally.
Place the device on the 4 rubber bumpers in front of you, so that the end with the
high position where you can feel the display is furthest away from you.
Upper side: All the keys can be found on the upper side. They are subdivided into
3 groups: The first group on the left side consists of 4 round keys. The second
group, left from the middle, consists of 3 rows, each including 3 bigger, squared
keys. The third group, to the right, consists of 4 rows, each including 4 squared
keys.
Right side: On the right side of the device, there are three outlets. The one nearest
to you is an earphone socket (earphones are optional and not included). Next to the
display there are the other outlets, where the socket for an optional power supply
(not included) is farthest away from you and the other one is a service outled for our
technicians.
Bottom side: On the bottom side of the device, you will find 4 rubber bumpers, the
loudspeaker grill and the battery compartment.
3: Power Supply
Batteries: Platon XL operates with 4 1.5 Volt AA batteries. The battery
compartment is situated on the bottom side of the device. To insert the batteries,
turn over the device with the high position end showing to the right side. Right from
the middle of the bottom side you can feel a little notch. This is where you can open
the battery compartment. Please note that the lid opens to the right and is not
completely removable! Put the 4 batteries in the compartment with the flat
(negative) end of each battery contacting the coil. Close the lid until it locks in
place.
Power Supply: Platon XL can also be operated with a power supply unit. The
power supply unit is not included in the delivery and has to be ordered separately!
The socket for the power supply unit is located next to the display: it’s the front
outlet on the right side of the device.
Caution: Replace the batteries as soon as the device
announces “battery weak”.

6
4: Keyboard Layout
The keyboard is subdivided into 3 groups: To the left there are 4 round keys, which
we call now “auxiliary keys”. In the middle, next to the auxiliary keys, there is the 3 x
3 group. To the right, the 4 x 4 group is located. The 4 x 4 group consists of 4 rows
with 4 squared keys, the 3 x 3 group consists of 3 rows with 3 squared keys. Each
key of the left located 3 x 3 group operates two functions.
In the following, we describe each row top down and group to group from left to
right.

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4.1: Groups of Keys and Auxiliary Keys
The keyboard layout will be described with the keys listed in groups. In each group
the functional description will move top down from left to right, where the keys
straight under the display are in the row number 1.
In the 3 and 4 matrices groups you can start a function by:
Press a key shortly
Press and hold a key
Press a key in level (layer) 2 or level 3
Use the shift key to change to level 2, 3 or back to base level. The shift-key is the
left key in row 1 in the 3 x 3 group. A short press activates the second level (“shift
2”) of functions connected to the keys and pressing long activates the third level
(“shift 3”). Press the shift key several times to switch between all the 3 levels. When
entering base level a short beep signal is played.
4.1.1: The 4 Auxiliary Keys
With respect to the XL product series, there are several settings on the 4 auxiliary
keys for different product types.
row 1 turn backlit display on/off
help mode on/off (type without backlit display)
row 2 increase volume
row 3 decrease volume
row 4 repeat input
4.1.2: 3 x 3 Group (from left to right)
row 1,
left key short = change level long = level 3
row 1,
middle key short = recall memory long = save value
level 2 = add value
row 1,
right key short = delete/turn on long = 1 step back
level 2 = delete 1 memory level 3 = delete all
memories
row 2,
left key short = square long = to the power of
level 2 = announce time
row 2,
middle key
short = repeat/return long = menu
level 2 = statistic mode

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row 2,
right key short = square root long = roots
level 2 = announce date
row 3,
left key short = left parenthesis
row 3,
middle key short = right parenthesis
row 3,
right key short = change sign long = reciprocal value
level 2 = 10 to the power of
4.1.3: 4 x 4 Group (from left to right)
row 1,
left key digit 7
level 2 = sinus level 3 = arcsine
row 1,
column 2 digit 8
level 2 = cosine level 3 = arccosine
row 1,
column 3 digit 9
level 2 = tangent level 3 = arctangent
row 1,
right key short = divided by long = modulo
level 2 = change display
row 2,
left key digit 4
level 2 = hyperbolic sine level 3 = area hyperbolic
sine
row 2,
column 2 digit 5
level 2 = hyperbolic cosine level 3 = area hyperbolic
cosine
row 2,
column 3 digit 6
level 2 = hyperbolic tangent level 3 = area hyperbolic
tangent
row 2,
right key short = times long = percent
row 3,
left key digit 1
level 2 = natural logarithm level 3 = e to the power of
x
row 3,
column 2 digit 2
level 2 = common logarithm level 3 = 10 to the power of
x

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row 3,
column 3 digit 3
level 2 = Pi level 3 = factorial
row 3,
right key minus
level 2 = convert to hours, minutes,
seconds level 3 = convert to decimal hours
row 4,
left key digit 0
level 2 = choice of angular
dimension level 3 = convert angular dimension
row 4,
column 2 short = point
level 2 = number of decimal places
row 4,
column 3 equals
row 4,
right key plus
4.2: Basic Functions
4.2.1: Switch the Device On and Off
To switch the device on, quickly press the ON-key (3 x 3 group, top right). Platon
XL will switch off automatically after a certain time without keystroke. To switch it off
manually, press and hold all 3 keys of the first row in the 3 x 3 group until you hear
a short jingle.
4.2.2: Menu Escape Function
To escape the menu, quickly press the ON-key (3 x 3 group, top right).
4.2.3: Delete Last Digit / Delete All
If you typed in a number incorrectly, you can always delete either the last digit or
the whole number. To delete the last digit, press and hold the ON-key (3 x 3 group,
top right). To delete the whole number, quickly press the ON-key.
4.2.4: Keylock
To activate or inactivate the keylock function, keep the 0-key and the plus-key
pressed until you hear a short confirmation (4 x 4 group, row 4, left and right key).
4.2.5: Volume Control
With the speech output version, there are 6 volume levels to choose from. The
volume level can also be set to 0. To increase the volume press the auxiliary key in

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row 2. To decrease the volume press the auxiliary key in row 3. Another way to
change the volume is in the 3 x 3 group: to increase the volume, shortly press the
menu key (3 x 3 group, row 2, middle key) together with the right key of row 2. To
decrease the volume press both, the menu key and the left key of row 2. Platon XL
will announce the volume.
4.2.6: Time and Date
Platon XL offers a built-in clock. To hear the time, press the “to the power of”-key in
level 2 (3 x 3 group in row 1, top left and than the left key in row 2). To hear the
date, press the root-key in level 2 (3 x 3 group in row 1, top left and than the right
key in row 2). Time and date are also available in standby mode of the device.
4.2.7: Repeat Function
By pressing the auxiliary key in row 4 or by pressing the menu key shortly (middle
key in row 2 of the 3 x 3 group) the entire entry can be announced, even before the
operation is finished.
4.2.8: Backlit Display (option)
With the backlit display version you could turn the light on and off by pressing the
auxiliary key in row 1.
4.2.9: Help Mode
Pressing the keys square and root at the same time (3 x 3 group, row 2, left and
right keys) leads you into the help mode. Here you are given a short note about the
function of the key you are pressing. By pressing square and root again you may
leave the help mode.
5: Calculations
Platon XL offers all standard arithmetic functions, as well as the possibility to
calculate percentages, extract roots or raise to higher power. You can also use
trigonometric functions, logarithms and hyperbolic functions.
The way of entering data is orientated in lines which means that you enter the
whole calculation first, than press the equals-key and the whole line is calculated.
With the equals-key you can repeat the result. With the repeat-function you can
repeat the whole line. If you have mistyped accidentially you could delete the last
digit or an operator and do correction. Numbers could be shown in scientific or in
Caution: The volume level can also be set to 0. Platon XL then
will give no announcements. This setting can be reseted by
cutting of the power supply (e.g. exchange the batteries).

11
technical formate. In addition you could set the number of digits as well as the
places of roundings.
5.1: Standard Arithmetic Functions
The standard arithmetic functions include: to add, to deduct, to multiply and to
divide. To conduct one of those standard functions, just type in the number followed
by the function (4 x 4 group, the right keys in each of the rows 1 to 4) and the
second number. To finish the arithmetic procedure, press the equals-key (4 x 4
group, row 4, column 3). The equals-key is designed in tactile with a short line.
Every key you enter, as well as the result of the calculation are announced in a
clear voice. To repeat the result of the calculation, press the equals-key once again.
If you accidentally type in a wrong number, just press and hold the ON-key (3 x 3
group, row 1, right key) to delete the last value. This is the way you can delete a
whole operation step by step backwards.
5.2: Advanced Arithmetic Functions
Platon XL also offers the possibility to calculate percentages, extract square roots
or square a given number.
5.2.1: Percentages
When calculating percentages the following approaches are most common:
Calculation Example Input
Percent How much is 5% of 250? 250 x 5 %
Percentage 250 is 5% of how much? 250 / 5 %
Surcharge How much is 250 plus a surcharge of 5%? 250 + 5 %
Rebate How much is 250 minus a rebate of 5%? 250 – 5 %
To calculate for example, how much are 5% of 250, type 250, then press the
multiplication-key (4 x 4 group, row 2, right key) followed by the digit 5. Finish the
process by pressing the multiplication-key long. Platon XL will then announce the
result.
5.2.2: Square and Raise to Higher Power
To square a given number, type in the value and shortly press the squared-key (3 x
3 group, row 2, left key) followed by the equals key.
To raise a given number to higher power type in the value, than press and hold the
squared-key (3 x 3 group, row 2, left key). Now enter the value of the exponent and
press the equals-key.
Example: If you wish to calculate 2 to the power of 3, press the digit-key for 2. Now
press and hold the squared-key (3 x 3 group, row 2, left key), than enter the
exponent with digit-key 3. The result will be given by pressing the equals-key. If you

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just want to square number 2, press the squared-key shortly and you will get the
result with the equals-key.
5.2.3: Roots
To extract a square root, type in the number and shortly press the square root key
(3 x 3 group, row 2, right key) followed by the equals-key.
To extract any root, type in the number and press and hold the square root key (3 x
3 group, row 2, right key). Now enter the order of the root and press the equals-key.
The order of the root does not have to be an integer.
Example: To calculate the third root out of 8 press digit key number 8, than press
and hold the square root key (3 x 3 group, row 2, right key). Now enter digit number
3 for the root of third order, followed by the equals-key. Platon XL will give the result
“22”. To calculate the second root out of 8, press digit key number 8, than press the
square root key shortly followed by the equals-key. The square root of 8 will be
displayed.
5.2.4: Reciprocal Value
To calculate the reciprocal value, type in a number and press and hold the ‘change
sign’ key (3 x 3 group, row 3, right key) followed by the equals key.
5.2.5: (Pi)
To calculate with the number (Pi), press digit key 3 in level 2 (3 x 3 group, row 1,
left key and than in the 4 x 4 group row 3 column 3).
5.2.6: Change Sign
Press the “change sign” key shortly to change the sign of a value (3 x 3 group, row
3, right key).
5.3: Scientific Functions
As scientific functions Platon offers you trigonometric functions, logarithms and
hyperbolic functions, as well as their inverse functions. With the 4 x 4 group keys in
level 2 or level 3 you select the scientific functions. Use the shift key to change to
level 2, 3 or back to base level. The shift-key is the left key in row 1 in the 3 x 3
group. A short press activates the second level (“shift 2”) of functions connected to
the keys and pressing long activates the third level (“shift 3”). Press the shift key
several times to switch between all the 3 levels. When entering base level a short
beep signal is played. To calculate with a scientific function, first enter a value then
choose the function.
Example: Calculation of cosine(0). Enter number 0. Choose the function cosine.
Press the equals-key to get the result “1”.

13
Abbreviations for scientific functions are printed next to the keys on the case of
Platon XL. Functions which are operated in layer 3 are printed in italic. For blind
and visually impaired people all functions with the keyboard layout are listed below:
5.3.1: Sinus
level 2, row 1, left key in 4 x 4 group
and numerical key 7 in level 2 respectively
5.3.2: Cosine
level 2, row 1, column 2 in 4 x 4 group
and numerical key 8 in level 2 respectively
5.3.3: Tangent
level 2, row 1, column 3 in 4 x 4 group
and numerical key 9 in level 2 respectively
5.3.4: Arcsine
level 3, row 1, left key in 4 x 4 group
and numerical key 7 in level 3 respectively
5.3.5: Arccosine
level 3, row 1, column 2 in 4 x 4 group
and numerical key 8 in level 3 respectively
5.3.6: Arctangent
level 3, row 1, column 3 in 4 x 4 group
and numerical key 9 in level 3 respectively
5.3.7: Hyperbolic Sine
level 2, row 2, left key in 4 x 4 group
and numerical key 4 in level 2 respectively
5.3.8: Hyperbolic Cosine
level 2, row 2, column 2 in 4 x 4 group
and numerical key 5 in level 2 respectively
5.3.9: Hyperbolic Tangent
level 2, row 2, column 3 in 4 x 4 group
and numerical key 6 in level 2 respectively

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5.3.10: Area Hyperbolic Sine
level 3, row 2, left key in 4 x 4 group
and numerical key 4 in level 3 respectively
5.3.11: Area Hyperbolic Cosine
level 3, row 2, column 2 in 4 x 4 group
and numerical key 5 in level 3 respectively
5.3.12: Area Hyperbolic Tangent
level 3, row 2, column 3 in 4 x 4 group
and numerical key 6 in level 3 respectively
5.3.13: Natural Logarithm
level 2, row 3, left key in 4 x 4 group
and numerical key 1 in level 2 respectively
5.3.14: Common Logarithm
level 2, row 3, column 2 in 4 x 4 group
and numerical key 2 in level 2 respectively
5.3.15: e to the Power of x
level 3, row 3, left key in 4 x 4 group
and numerical key 1 in level 3 respectively
5.3.16: 10 to the Power of x
level 3, row 3, column 2 in 4 x 4 group
and numerical key 2 in level 3 respectively
5.4: Conversions
Due to the default conversion settings, the conversion function enables you to
quickly calculate e.g. how many miles 10 kilometers are. Press and hold the menu
key (3 x 3 group, row 2, middle key) and choose “conversions” from the menu with
the right or left key of the second row in 3 x 3 group. Press and hold the menu key
again to enter the conversions submenu. By shortly pressing the left or right key
again, you can now select the measurement unit you would like to work with. You
can choose between the following units: currency (from US Dollar to Euro),
temperature (from °C to °F), volume (from liters to gallon), length (from kilometers
to miles), weight (from kilogram to pound) and customed conversion (for your very
own conversion rate).

15
To choose for example “temperature”, shortly press the menu-key (middle key in
row 2 in 3 x 3 group) and Platon XL will once again announce the conversion rate.
You can now type in the number you like to convert, e.g. 30. To convert this number
into degree Fahrenheit, press both the point-key and the equals-key (4 x 4 group,
row 4, columns 2 and 3) and Platon XL will announce “degrees Celsius equals 86
degrees Fahrenheit”. To re-convert this result to degree Celsius, press both the
equals-key and the plus-key (4 x 4 group, row 4, columns 3 and 4).
5.4.1: Currency Conversion
The default setting of the Platon XL provides the conversion from Euro to US Dollar
and vice versa, with an exchange rate 1.373. You can easily adapt the exchange
rate. To do so, choose the function “currency” from the conversions submenu and
press and hold the menu-key (3 x 3 group, row 2, middle key). Type in the
exchange rate you need and confirm by shortly pressing the menu-key again.
Platon XL will now use this new exchange rate when converting currencies.
5.4.2: Custom Conversion
If the default settings do not offer the conversion you are looking for, you can set
your individual conversion rate by choosing the function ‚custom conversion‘. When
the function is selected, press and hold the menu-key (3 x 3 group, row 2, middle
key) and type in the conversion rate you need. Confirm by shortly pressing the
middle key. You can now calculate with your individual conversion rate.
5.5: Financial Calculator
Platon XL also offers you commercial formulas to calculate compound interest, net
present value or annuities. To activate the formulas, choose the function ‘financial
calculator’ from the conversions submenu and press and hold the menu-key. Select
a formula by shortly pressing the right or left key of the same row and confirm by
pressing and holding the the menu key.
5.5.1: Compound Interest
This formula helps you to calculate an end capital on the basis of a certain initial
capital and a given duration and percentage.
Example: You have a certain amount of money (initial capital) on your savings
account. You know, that your bank offers you a certain interest rate (percent) and
you decide to keep this amount of money on your account for e.g. 5 years
(duration). After typing in all this information, Platon XL will announce how much
money you will have on your savings account after those 5 years including the
interest given by your bank.
After selecting the formula, Platon XL asks you to type in the initial capital. Do so
and confirm by shortly pressing the menu key (3 x 3 group, row 2, middle key).
Platon XL repeats the value and asks you to type in the percentage. Do so and
confirm by shortly pressing the menu key again. Platon XL will repeat the percent

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and ask you to type the duration. Do so and once again confirm by shortly pressing
the menu key. Platon XL then will announce the end capital.
5.5.2: Net Present Value
This formula helps you to calculate the initial capital on the basis of a certain end
capital you wish to have in the near future (including the interest).
Example: You know, you need a certain amount of money in the near future (end
capital) and you know that your bank offers you a certain interest rate (percent).
You decide to keep money on your savings account for e.g. 5 years (duration). After
typing in all this information, Platon XL will calculate the net present value. This is
the amount of money, you have to invest in order to reach said end capital.
After selecting the formula, Platon XL asks you to type in the end capital you wish
to reach. Do so and confirm by shortly pressing the menu key (3 x 3 group, row 2,
middle key). Platon XL repeats the value and asks you to type in the percentage.
Do so and confirm by shortly pressing the menu-key again. Platon XL will repeat
the percentage and ask you to type in the duration. Do so and once again confirm
by shortly pressing the menu-key. Platon XL then will announce the net present
value.
5.5.3: Annuity
The term annuity is used in finance theory to refer to any terminating stream of
regular payments over a specified period of time.
Example: You obtain a credit from your bank (initial capital). You pay a certain
percentage of interest for this credit (percent) and you also know that the credit is
due within the following 20 years, that is 240 months (duration). After typing in all
this information, Platon XL will calculate the monthly installments you have to pay in
order to repay the credit.
After selecting the formula, Platon XL asks you to type in the initial capital. Do so
and confirm by shortly pressing the menu-key (3 x 3 group, row 2, middle key).
Platon XL repeats the value and asks you to type in the percentage. Do so and
confirm by shortly pressing the menu-key again. Platon XL will repeat the percent
and ask you to type in the duration. Do so and once again confirm by shortly
pressing the menu-key. Platon XL will then announce the regular payment due.
5.5.4: Annuity Initial Capital
This formula offers you the vice versa calculation, that means, you can find out
which credit amount you could afford.
Example: You know how much money you could afford each month to pay
installments (annuity). You know the conditions of your bank, that is the interest
rate (percent) as well as the time (duration). After typing in all this information,

17
Platon XL will calculate the credit you could afford to pay back with the amount
monthly available.
After selecting the formula, Platon XL asks you to type in the annuity. Do so and
confirm by shortly pressing the menu-key (3 x 3 group, row 2, middle key). Platon
XL repeats the value and asks you to type in the percentage. Do so and confirm by
shortly pressing the menu key again. Platon XL will repeat the percentage and ask
you to type in the duration. Do so and once again confirm by shortly pressing the
menu key. Platon XL then will announce the initial capital possible.
5.6: Memory Function
5.6.1: Save Values
In order to save numbers in memory, choose the function “save value“ (press and
hold the button in the middle of the first row in 3 x 3 group) and select a memory
cell from number keys 1 to 9. This way the value is stored in the appropriate
location (there are up to 9 different memory locations).
5.6.2: Select Stored Values
Use the function “recall memory“ (short press on the middle button of the first row in
3 x 3 group) and then press the corresponding number key to select the value from
a memory location (1 to 9).
5.6.3: Add Up Additional Values
With Platon XL you can add new values to stored values. To do so, use the memory
key in level 2 and select a memory cell from number keys 1 to 9. The new value will
be added to the stored value.
5.6.4: Delete Stored Values
In order to delete a stored value, press the ON-key (3 x 3 group, top right) in level 2
and than select the corresponding memory cell. In order to delete all stored values,
press the ON-key in level 3. To write any new value in memory, just save the value
to the appropriate memory location. You can also delete a stored value by saving
the value ‘0’ to the appropriate memory location.
6: Statistics
Use the menu-key in level 2 to enter the statistic mode (3 x 3 group, top left key and
than the tactile menu-key in the middle).
6.1: Keyboard Layout in Statistic Mode
In the statistic mode the keyboard layout for 3 x 3 group is:

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row 1,
left key short = change level long = level 3
row 1,
right key short = exit statistic mode long = 1 step back
row 2,
left key short = arithmetic mean value long = geometric mean value
row 2,
middle key level 2 = exit statistic mode
row 2,
right key short = root mean square value long = harmonic mean
row 3,
left key short = sum of all values long = product of all values
row 3,
middle key short = standard deviation long = number of all values
row 3,
right key short = sum of the squares long = sum of reciprocal values
In 4 x 4 group there are the numerical keys, and the operator-keys minus and plus
are set with the following functions:
row 3,
right key subtract a number
row 4,
right key add a number
6.2: Usage of the Statistic Functions
You could add and subtract numerical values to work with in statistic mode. Platon
XL offers the following statistic functions:
arithmetic mean value
geometric mean value
root mean square value
harmonic mean
standard deviation
calculation of:
number of all values
sum of all values
sum of the squares
sum of reciprocal values
product of all values
Example: You want to work out the arithmetic mean and the standard deviation of a
number of values.

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1. Enter the statistic mode by pressing the menu key in level 2 (top left key, than
the tactile middle key in the 3 x 3 group). In statistic mode the word “statistics”
is announced and top right on the screen all the 3 angular dimension signs
(DEG RAD GRAD) are shown.
2. Enter the number series (example 3 – 4 – 5):
digit 3 and plus key (4 x 4 group, row 4, right key) – output “add value”;
digit 4 and plus key – output “add value”;
digit 5 and plus key – output “add value”.
3. Calculation of the arithmetic mean: square key (3 x 3 group, row 2, left key) –
output “arithmetic mean” result “4”.
4. Calculation of the standard deviation: right parenthesis key (3 x 3 group, row
3, middle key) - output “standard deviation” result “0.816496581”.
5. In order to check whether all values have been entered, you have the
possibility to ask Platon XL to tell you the number of entered values: Press
and hold the right parenthesis key (3 x 3 group, row 3, middle key) – output
“number of values” result “3”.
Exit the statistic mode with the menu key in level 2 (3 x 3 group, top left key and
than the tactile middle key).
6.3: Help in Statistic Mode
Pressing the keys square and root at the same time (3 x 3 group, row 2, left and
right keys) leads you into the help mode in statistic mode. Here you are given a
short note about the function of the key you are pressing. By pressing square and
root again you may leave the help mode.
6.4: Faculty
The faculty of a number can be calculated outside of the statistic mode: Enter a
number and use the digit key for number 3 in level 3 (level 3 and than row 3,
column 3 in the 4 x 4 group).
Example: To calculate the faculty of 5, press digit key 5 (4 x 4 group, row 2, column
2), than change to level 3 (3 x 3 group, top left, press long or twice) and press digit
key 3 (4 x 4 group, row 3, column 3). Pressing equals (4 x 4 group, row 4, column
3) will give you the result “120”.
Please note that you can’t do any other calculations in the
statistics mode.

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7: Menu
In the menu you can setup different function settings and start the commercial
calculator and the conversions. Enter the menu by pressing the menu key long. The
menu key is placed in the middle of the 3 x 3 group and marked with 3 tactile
points. Any point from the menu will be announced (or shown on display in mute
version devices). You can browse through the menu by shortly pressing the left or
right key next to the menu key. To choose one of the menu functions, press and
hold the menu key again. The same way you could navigate in each submenu.
Exit Menu
Press the ON-key (3 x 3 group, top right) to leave the menu or any submenu.
7.1: Structure of the Menu
Conversions
Custom Conversions
Currency
Temperature
Capacity
Distance
Weight
Financial Calculator
Compound Interest
Net Present Value
Annuity
Annuity (Initial Capital)
Settings
Volume
Number Announcement Format
Entire Number
Individual Units (Digit by Digit)
Decimal Places
Display Mode
Floating Decimal
Scientific
Engineering
Angular Dimensions
Degree
Radian
Grad
Clock
Alarm Clock
Time
Date