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[tdf-discuss] Fwd: Calc for engineering

---------- Forwarded message ----------
From: Matthew Parker <>
Date: Wed, Aug 14, 2013 at 7:53 PM
Subject: Calc for engineering


I write regards the focus on calc for office use. Why not engineering,
astronomy etc?

I am using it for Solar calculations and to develop a dashboard for instant
quotations and engineering clacs.

Attached are some screen shots. The sun tracking sheet takes the position
of the Sun's incline and azimuth every 15 min for a whole year. One month
is about 30 columns and 1400 rows. The file is already 20MB and my computer
cannot handle more.

As an electrician, and pretty good trigonometry I attempted this file based
it on an astronomy calculator published by NOAA whom gave me permission to
use as I wish for business. See

My suggestion:

Look at PLC programming in industry. It stands for Programmable Logic
Controller. Some programmers use code but for electricians we use ladder
logic because it looks like wiring.

What to look at:

The functions; counters, timers, shift registers, etc, etc and what I
really need for my solar software LATCHING CELLS!!!!!!!!!!!!!

These functions and more introduce the dimension of TIME which PLCs need
absolutely to run machinery.

Also known as sequencial control it introduces the dimension of TIME

E.g. When limit switch I34 is active, turn off O56 (a motor driving a
conveyor) and start timer T1 (while a paint tin is filled for example)
which then turns on the conveyor again when timed out.

OK, no need to go all out but please consider the function for Latching and
sequencing through such latch function.

With latching cells I could have 1 sheet for one month of sun tracking, not
12 sheets since I could use the same sheet for all 12 months. As you may
see in the NOAA spreadsheet, it has one cell to change the date. If I could
latch the results of January to a table I could change the date on the
sheet to Feb, latch those results and move on, etc, etc,

Perhaps - =if($B$1="January", A1, LATCH) which is; if B1 = "January" then
insert the results of A1 otherwise latch then pull down or across or both
for multiple cells since B1 is locked with $ symbols.

A drop down menu could change month in B1 or as I would need:

A sequencer function - = CYCLE(B1,A1:A12,If(.....)) which would run one
cycle of each month from range A1:A12 through cell B1 If whatever button is
pressed or condition is set.

Just hypothesising.

Anyway, I could crunch my 20MB spreadsheet into 1/12th the size.

PLCs use a "watch dog timer" to cycle through the program before taking the
next step otherwise I might get May data in my September table.

In Utopia, if there was total functionality of a PLC in calc one could
automate an entire office building with input and output modules and leave
MSO looking rather ancient BUT the trick is however, PLCs just use software
as a HMI and rely on solid logic and military grade electronics to actually
run the program to insulate from crashing.

But at least consider latching functions and a few sequencing controls. It
would really really multiply the capacity of calc for as many times one
could recycle their large data tables with different inputs.

Please reply with thoughts on this concept.

P.S. What can I do to make my program run effectively? I tried having 12
files open at once and linking to my dash board file but the links do not

Matt Parker <>


 REC 13198

ABN 890 1930 6213

Ph. 0466 96 2222



Matt Parker <>


 REC 13198

ABN 890 1930 6213

Ph. 0466 96 2222


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