S3aCalc
A Calculating Revolution
for the Psion Series 3a

by Nick Buckenham & John Crook

Why another calculator for the Series 3a? It's already got one!
The Psion Series 3a is infinitely better than the old Organiser .... except in one respect. It doesn't have a numeric keypad! Any serious number cruncher will soon give up when he/she has to use the top row of the keyboard.
Hence S3aCalc......

As you can see from the first Help Screen  the U,I,O,J,K,L & M keys have been used as a standard numeric keypad. Of course the original keys can also be used at the same time.

The Hardware Changes.
Just cut out and stick on the numbers 0 to 6, the % and the "," and "." on the keyboard and you are away! (See Help screen.) You can make the labels from any "sticky" labels or send œ12 to us and we will send you a set - see Shareware below.

Loading the Program.
The program is an "application" which should be installed via the system "Apps" menu. (See the Psion manual.) Copy both programs  to the APP directory on the A, B or Internal drive. It can be allocated to one of the "Buttons". It expects an icon file ("\APP\S3aCalc.pic") on the same drive as "\APP\S3aCalc.opa". Once run a small data file is also created on the APP directory of your "default" drive.

What makes S3aCalc special?
*	It has the look and feel of a numeric keypad calculator.
*	It has a unique stored calculation feature which is so much more than just a constant function.
*	VAT calculations are built in.
*	The last six calculations and answers can be retrieved.
*	Two directly addressable memories.
*	Fully flexible format and decimal display.
*	Thousands separators.

Using the Calculator.
It is quite straight forward. Try entering some sums - using either or both sets of number keys. Hit enter. The answer appears and the original sum moves up. The answer is repeated on the right.  If you start a new sum the previous answer clears ready for the new sum. If, however, an operator (+, -, / or *) is pressed the previous answer remains. Each time Enter is pressed the answer appears and the previous sums move up through the six registers. (An answer is always preceded by an "=" sign.)

Help Screen.
Press the Help key for a graphic display of the Numeric Key Pad and other useful hints.

A Word about the Display.
S3aCalc holds answers to one level of accuracy and displays to another. An accountant may want to use an accuracy of 2 dec. places and display 2 dec. places. An engineer may wish to display 3 dec. places but hold to 6 dec. places. The options can be set via the Menu. (See below). In addition the format can be General or Scientific.

Editing the Current Sum.
The cursor keys will move the cursor along the current sum. The Psion key plus the left or right arrow moves the cursor to the start or end of the line. The Control key and a cursor key moves the cursor 10 places. The delete key deletes the character to the left of the cursor. Shift Delete deletes the character under the cursor.

Editing a Previous Sum.
Use the Up arrow and a small arrow will appear instead of the equals sign.  Hit enter and a previous answer  is copied down to the current register at the cursor position. If the input register holds an answer it will be replaced by the new figure. Once the arrow is up in the registers the left and right arrows can be used to switch between the answers and the sums held in the registers. 
Alternatively "Psion E" edits (rotates) the registers to allow changes to be made or a sum repeated.

Menu/Hot Keys.
The menu key gives access to all the functions. (You can also use the Psion hot keys.) (Except for the top memory - see below.)

Memories Card
Any two of the usual memories (M0 - M9) can be accessed. The particular  memory numbers you want to use are set via the Settings menu card.
The second memory can be addressed using the menu card or the Psion hot keys. The fist memory can only be addressed by using the Control key instead of the Psion key.
The memory menu card is self explanatory! Any of the memories can be included in a sum by typing its name in directly. (ie. 3+17-M2).

The Auto Calcs Card
The first four options control the Stored Calculation function. The following example will illustrate the features. Assume you have to find what percent of 157 is each of the following amounts - 12, 34, 42, 66. First store the calculation using the letter N to indicate the variable in the calculation. Do this as follows:
*	Type Shift+N/157%  (This displays as N/157%)
*	Select menu option Store Calc or use the hot keys (Psion+Shift+S). The formula will appear on line three of the top section of the  display and the input line will clear.
*	Enter the first value ie 12 and select menu option Use Stored  or hot keys (Psion+S).  The formula will be retrieved, the "N" replaced with "12" , the sum will  display on the first line of the register and the answer (7.64) will show on the input line. 
Enter the next number (ie 34) and (Psion+S)  and the next answer (21.66) will appear. Simple!
*	Amend Stored (Psion+A) allows the stored calculation to be edited.
*	Zap Stored (Psion+Shift+Z) clears the stored calculation.

The Edit  Stack (Rotate) key has already been mentioned.

Zap the Stack clears the registers but leaves the  memories and the Stored Calculation  intact. 

The Vat key. Enter a Vat inclusive figure in the input line. Hit Psion V and the net figure appears in the answer. BUT look at the register above. The Gross figure is displayed followed by the Vat amount. For example enter 117.5 and hit Psion V. The answer shows 100.00 and the register shows 117.5-17.5.
Conversely if you follow the figure you enter with a "+" the Vat will be added. ie from net to gross. eg. enter 100+ and hit Psion V and the answer is 117.50 and the register shows 100.00+17.50.

The "Settings" Menu Card.
The first four options should be self explanatory.
 The Percent VAT allows the rate held to be changed from the default of 17.5%. See below for the VAT key.
The Thousands option is unique. It turns  on a row of 000's markers to help when reading long numbers.

The "Others" Menu Card.

Exit leaves the program but leaves the memories, the stored calculations and default settings intact in the S3aDat file.

Origin tells you where to send your œ12! (See below.)

Some Hints and Tips.
Most functions can be applied to sums as well as answers. If, for example, you want to put the answer of a sum into memory just enter the sum and hit Psion or Control+I and the answer is displayed and put in memory.
To type in letters (e.g. LOG) use the Shift key.
Trig works but only uses Radians. To find the Tan of 45 degrees type TAN(RAD(45)).

Note S3aCalc will only run on the Series 3a.

Copyright 
John Crook & Nick Buckenham
 This software is available as Shareware. It may be passed on to others. Please send œ12 if you find it useful. A set of key labels will be sent by return. Cheques payable to John Crook.
Pencoed Software, Sheets Heath, Brookwood
Woking, Surrey, GU24 0EL.
Disclaimer.
Care has been taken to check this software fully. However no responsibility can be accepted for any loss , either direct or indirect, arising from errors in the program or for any other reason.

October 1994.
Issue 94/09