No Twitch Servos

[AndyB]

This is one way to prevent interference affecting servos particularly when they are some distance from the servo driver/controller.

 

[Andrew Duncan]

Hello Andy
I know we've discussed this before, a year or to ago, but when you say "some distance" what sort of distance are you thinking of?
Andrew

 

[Tony W]

Hello Andy
I know we've discussed this before, a year or to ago, but when you say "some distance" what sort of distance are you thinking of?
Andrew

Hi Andrew.
I think it would depend on how noisy the particular environment is. If trouble is experienced then I can see how this circuit would cure the problem.
Regards
Tony.

 

[AndyB]

Hello Andy
I know we've discussed this before, a year or to ago, but when you say "some distance" what sort of distance are you thinking of?
Andrew

Hi Andrew,

That depends on how much electrical noise there is in your environment. Radio controlled planes, boats etc are usually a great distance from spark generators which is why servos don't have a problem in those situations.

Model railways usually have lots of things that can produce arcs and long wires and rails that act as antennae to transmit the energy all over the place. There are also the operators who can produce whopping great arcs when they discharge themselves during periods of low humidity Then there might be thermostats and fluorescent lights which are also good arc generators.

I've been able to upset servos just with the cable that comes with them although that's a rather extreme case. Put it this way, if I was selling a piece of equipment that incorporated these servos I would shorten the cable and put the drive electronics no further than a couple of inches from the actual servo.

Many people will tell you they don't have any trouble all. They might say I'm just being an alarmist but they didn't spend years hardening commercial electronic equipment to prevent it producing interference and making it immune to interference from all sorts of sources. There's a lot more to digital electronics than ones and zeros

At the very least I would not extend the cables at all but it's really just a case of whether you are willing to take a chance and hope you don't have any problems or invest more time and energy to ensure you don't have any problems. You could try some tests of course but it can take a lot of time to identify the worst case. Typically that only reveals itself after everything is screwed, glued and bolted down.

If I was in the UK I'd sell optoisolator cards or kits for servos but it would be far too complicated to sell them from here.

Sorry if that doesn't really answer your question but the bottom line is the input to the servo is not designed to operate in electrically noisy environments.

Cheers.
Andy

 

[AndyB]

Addendum:

I thought it might be worthwhile adding a bit more explanation about what's going on here.

Any time there is a sudden change in the current flowing in a conductor the conductor (wire) acts as an aerial and the aerial couples energy into the thing currently referred to as "space-time" (except that nobody knows what space-time really is - we just have to accept that we know how it behaves.) That's all radio waves are and it's how Marconi was able to use a spark generator to send transatlantic communications without a cable. The more rapid the change the greater the energy coupled and that's why arcs and sparks are so good at it.

Any conductor will accept some of that transmitted energy and the longer the conductor the more energy it will receive. If enough energy is received it can induce a voltage in the conductor that, in digital terms, makes a one look like a zero or a zero look like a one. (Servos have a digital interface and because a change in polarity will trigger a "cycle" we really do not want a false change in polarity.)

The optoisolator circuit above will also receive the energy generated by some nearby spark but because the signal flows along a twisted pair an equal amount of energy will be induced in the pair's return wire. The two voltages cancel out and the current cannot flow anywhere other than back to the source end because there is no galvanic (fancy word for electrical) connection for the current path. It's purely a light beam and it doesn't give a hoot about feeble radio-frequency interference.

The snag with optoisolators is they are not so good at sending high frequency digital signals but servos operate with very low frequency digital signals making this an ideal application for optoisolators.

BTW, older fangled computer equipment tended to be quite susceptible to EMI (Electro Magnetic Interference) but one of the advantages of continually shrinking phenomenal numbers of transistors on to incredibly small pieces of silicon is that the interconnecting "wires" are so short that they can only collect tiny amounts of EMI.

Here's one of my last chips. Very "old hat" now. This was from about 17 years ago

 

[Stephen Freeman]

Some of the better servo controllers (MERG) have pull-up resistors built- in as an option plus you can also switch off the signals being sent. If the controllers haven't got pull-up resistors built in, a 10k resistor between positive and signal will help.

 

[AndyB]

Some of the better servo controllers (MERG) have pull-up resistors built- in as an option plus you can also switch off the signals being sent. If the controllers haven't got pull-up resistors built in, a 10k resistor between positive and signal will help.

I've tested all sorts of "fixes" but they do not pass my test. The only thing that really works is the optoisolator.

 

[Andrew Duncan]

Hi Andrew,

That depends on how much electrical noise there is in your environment. Radio controlled planes, boats etc are usually a great distance from spark generators which is why servos don't have a problem in those situations.

Model railways usually have lots of things that can produce arcs and long wires and rails that act as antennae to transmit the energy all over the place. There are also the operators who can produce whopping great arcs when they discharge themselves during periods of low humidity Then there might be thermostats and fluorescent lights which are also good arc generators.

I've been able to upset servos just with the cable that comes with them although that's a rather extreme case. Put it this way, if I was selling a piece of equipment that incorporated these servos I would shorten the cable and put the drive electronics no further than a couple of inches from the actual servo.

Many people will tell you they don't have any trouble all. They might say I'm just being an alarmist but they didn't spend years hardening commercial electronic equipment to prevent it producing interference and making it immune to interference from all sorts of sources. There's a lot more to digital electronics than ones and zeros

At the very least I would not extend the cables at all but it's really just a case of whether you are willing to take a chance and hope you don't have any problems or invest more time and energy to ensure you don't have any problems. You could try some tests of course but it can take a lot of time to identify the worst case. Typically that only reveals itself after everything is screwed, glued and bolted down.

If I was in the UK I'd sell optoisolator cards or kits for servos but it would be far too complicated to sell them from here.

Sorry if that doesn't really answer your question but the bottom line is the input to the servo is not designed to operate in electrically noisy environments.

Cheers.
Andy

Andy
Thank you for your very full and clear explanations, speaking as one, who I know you know, has very little clue about electricity let alone electronics, you've done a pretty good job of enlightening me. With cables anywhere from 8" to 24" long between servo and Megapoints control boards, I've understood that this may elicit some unwanted interference.

So my further question to you is "If that was the case, were I to fit one of your box of tricks(circuit) to each servo, might I expect that to solve the problem?". In other words, if the worst comes to worst, can I retrospectively fit a circuit that sorts the problem out?

Last question is what is the large round thing that you say is 17 years old and looks like a mirror?

Kind regards
Andrew

 

[AndyB]

Andy
Thank you for your very full and clear explanations, speaking as one, who I know you know, has very little clue about electricity let alone electronics, you've done a pretty good job of enlightening me. With cables anywhere from 8" to 24" long between servo and Megapoints control boards, I've understood that this may elicit some unwanted interference.

So my further question to you is "If that was the case, were I to fit one of your box of tricks(circuit) to each servo, might I expect that to solve the problem?". In other words, if the worst comes to worst, can I retrospectively fit a circuit that sorts the problem out?

Last question is what is the large round thing that you say is 17 years old and looks like a mirror?

Kind regards
Andrew

Hi Andrew,

Yes, you could certainly see how you get on without any modifications. You might not experience any problems but if you do you could always add the optoisolators later.

The big round thing is a silicon wafer. Each little square thingy is a digital communications chip with many thousands of transistors on it. It's reflective because of the aluminum interconnections between the transistors. The wafer would ultimately be diced up and the individual chips would be encased in a package with metal contacts that you will be familiar with. There was a design error in that particular version of the chip so we had some of the wafers mounted for display purposes.

Cheers,
Andy

 

[Andrew Duncan]

Hi Andrew,

Yes, you could certainly see how you get on without any modifications. You might not experience any problems but if you do you could always add the optoisolators later.

The big round thing is a silicon wafer. Each little square thingy is a digital communications chip with many thousands of transistors on it. It's reflective because of the aluminum interconnections between the transistors. The wafer would ultimately be diced up and the individual chips would be encased in a package with metal contacts that you will be familiar with. There was a design error in that particular version of the chip so we had some of the wafers mounted for display purposes.

Cheers,
Andy

Thanks, Andy, that's good to hear that I can do something retrospectively if needed.

Impossible to imagine thousands of transistors in that area, and now this is old hat....strewth!

Andrew

 

[AndyB]

Hi Andrew,

I found a bit more information on that particular silicon wafer. Each chip (the little squares) consists of around 19.5 million "gates". A gate is at least two transistors so we can safely assume there are 40 million transistors on each chip, and that was 17 years ago. The "state of the art" has likely progressed quite a long way since then.

This is the stuff that we all take for granted these days but it is truly amazing. I happened to stumble into it 50 years ago. My great claim to fame is I discovered a defect in Intel's 8080 before Intel knew about it. At that time one 8080 chip cost more than my annual salary at Strathclyde Uni.

I just happened to be in the right place at the right time.

Cheers,
Andy

 

[Andrew Duncan]

I expect I should know what an 8080 is, but somehow I’ve a feeling one could come up and hit me in the face and I wouldn’t know it. I’m going to live dangerously, take a wild guess! Was it a predecessor to the 486(?) or Pentium chip. My first computer was a 486(if I’ve remembered the number correctly) latterly running Multi User DOS for our EPOS stock control system.All pretty leading edge in 1994. All cost an arm and a leg but maybe not a year’s salary! It gave me insights into the business that previously we’d only dreamt of.
Sorry I’m rambling and possibly nothing whatsoever to do with an 8080?
Kind regards
Andrew

 

[Martin Wynne]

I expect I should know what an 8080 is, but somehow I’ve a feeling one could come up and hit me in the face and I wouldn’t know it.

Hi Andrew,

The 8080 is the microprocessor computer chip (integrated circuit) that started the entire personal computer industry:

linked from https://sm.pcmag.com/t/pcmag_uk/photo/i/intel-8080/intel-8080_qwpp.1920.jpg

Info: https://uk.pcmag.com/opinion/38374/creating-the-8080-the-processor-that-started-the-pc-revolution

What you are looking at is a slab of ceramic (later plastic) about 2" x 1/2" having 2 rows of 20 pins, which were soldered into holes in a printed circuit board. Buried in the plastic is the actual 8080 silicon chip, linked to the pins with fine gold wires.

The 8080 was introduced by Intel in 1974, and finally ceased production in 1990 when the world had moved on to far more complex later chips. But the 8080 started it. Intel's fascination with the number 8 in their part numbers is based on the 8-bit internal design of the original 8080, and the 8-bit byte remains the basic building block of most modern computing. If the 8080 had had 9-bit internal registers, almost every program written today would have been different. Including Templot, which I started on only 5 years later. The rate of progress in those early days of microprocessors was amazing.

cheers,

Martin.

 

[AndyB]

Thanks Martin.

I was a tech at Strathclyde and I built a little computer around the 8080. We could only afford to buy one chip so switching it on for the first time was a bit exciting.

I thought it would be interesting to use interrupts to handle a peripheral interface but I could not get it to work properly. Eventually I was able to use an oscilloscope to see that the 8080 was not acknowledging the interrupt according to the spec.

Contacted Intel and told them what I had found. Two weeks later they called back and told me there was an error in the data sheet. The revised data sheet included a mysterious nand gate that had to be inserted between the 8080 and the interrupt logic!

They never did fix the chip

 

[Jim Guthrie]

I remember those times. In the late 1970s I started messing around with a National SC/MP chip, then moved on to an 8080 home-built computer which I've still got under my workbench in the garage - and I can't remember the name of the computer. I might even go out and dig it out of the cobwebs to see if I can find its name on the motherboard. I moved into management in 1982 and managed to blag a "proper" PC - an HP150 with a 15Mb hard drive - the separate hard drive in its case was as big as the HP150 case. The HP150 was one of the first PCs with the small 3.5" floppies. That PC actually did a lot of hard work in the office running a program to help out with our finance reporting.

Jim.

 

[AndyB]

The little machine I built around the 8080 had no ROM memory so you had to key-in a bootstrap loader from the front panel. The department's prof wrote the loader and he was boasting that it was only ten bytes and it could not possibly be made any smaller. That was before I showed him how to get it down to eight bytes (I think he took a rather dim view of me after that.)

 

[Andrew Duncan]

Thanks for the history lesson Martin. Do you mean that all the stuff around 8 bits such as 16, 32 and 64 bit computers, the RAM sizes are all down to Intel's facination the number eight?
Andrew

 

[Martin Wynne]

Thanks for the history lesson Martin. Do you mean that all the stuff around 8 bits such as 16, 32 and 64 bit computers, the RAM sizes are all down to Intel's fascination the number eight?
Andrew

Hi Andrew,

Not quite. In binary arithmetic the powers of 2 (2,4,8,16,32...) are the natural working sizes. Just as in everyday decimal arithmetic the powers of 10 (10,100,1000...) are the natural working sizes.

But it wasn't a given that the early microprocessors had to choose the 3rd power of 2, i.e. 8, as the basic building block. Some earlier processors were 4-bit designs. The IBM computer which I worked on in the early 1970s before the dawn of PCs was a 16-bit design.

It's possible to design processors with other bit counts, such as 12-bit -- the best known 12-bit designs were the PDP minicomputers of the 1960s -- $18,500 to you:

https://en.wikipedia.org/wiki/PDP-8

As microprocessors rapidly developed, the original 8-bit designs soon gave way to the later 16-bit and 32-bit processors.

But Intel remained glued to the number 8 -- if you look in your C: drive root folder, you will see a folder to this day called Program Files (x86) -- the 86 there being a reference to Intel chip part numbers.

cheers,

Martin.

 

[Tony W]

Hi Martin.
I still think how remarkable it was that the Apollo moon landings were achieved using 4 bit processors and by todays standard miniscul amounts of memory, indeed the development of micro processors was largely driven by the space race during the 1960s.
My first encounter with micro processors was with the 8085 chip set, which was Intel's successor to the 8080 and very similar. I was involved with several projects at work using them. Most of my work was on the hardware side, but I did get involved with the software side later on.

Hi Andrew.
I may regret starting this but...........
There is nothing sacred about counting in 10s (Decimal, base ten). We are so used to it because we have ten digits, i.e.fingers and thumbs, but it is possible to count using any base number. 2 (Binary), 8 (Octal), 16 (Hexadecimal) are the most commonly used as they are all powers of 2.
The basic principle is to count up until the base number is reached and then simply carry one and start counting again. At first the concept takes a while to grasp with our decimal schooled minds, but once the basic principle is mastered, it is not so difficult. I must admit that it was a bit of a revelation when first explained to me many years ago.
Regards
Tony.

 

[Andrew Duncan]

Hi Martin.
I still think how remarkable it was that the Apollo moon landings were achieved using 4 bit processors and by todays standard miniscul amounts of memory, indeed the development of micro processors was largely driven by the space race during the 1960s.
My first encounter with micro processors was with the 8085 chip set, which was Intel's successor to the 8080 and very similar. I was involved with several projects at work using them. Most of my work was on the hardware side, but I did get involved with the software side later on.

Hi Andrew.
I may regret starting this but...........
There is nothing sacred about counting in 10s (Decimal, base ten). We are so used to it because we have ten digits, i.e.fingers and thumbs, but it is possible to count using any base number. 2 (Binary), 8 (Octal), 16 (Hexadecimal) are the most commonly used as they are all powers of 2.
The basic principle is to count up until the base number is reached and then simply carry one and start counting again. At first the concept takes a while to grasp with our decimal schooled minds, but once the basic principle is mastered, it is not so difficult. I must admit that it was a bit of a revelation when first explained to me many years ago.
Regards
Tony.

Hello Tony
You may indeed regret it because whilst my son is a mathematician and computer programmer, he didn't get those two abilities from me, for sure, as I have some very basic mental blocks about maths that I've never really got over since school. An example being "how can -2 plus -2 = +4". Another is, if I have one of something, and multiply it by zero it then equals zero. To my mind, if I have an apple in my hand multiplying it by zero doesn't magically make it disappear!

So having exposed myself to certain amounts of ridicule (how can he believe this?) you will see that Binary let alone Hexadecimal is probably a bridge or two, too far! I suppose I live in a world of margins and percentages and does the profit we make pay for our overheads, and this is a world I'm at home in. And by comparison, it's very simple indeed. One of positives (profit) and negatives (overheads) and can we achieve the former more often than the latter?

Having said that I love learning about new things and from time to time Jonathan (son) has explained some of the finer points of maths to me and at the time I've quite often understood him, to my surprise. But probably because of lack of practice the explanation dims with time and eventually disappears. Having said that I've a horrible feeling that the CV's in loco chips use something pretty frightening in their makeup, dont they?

Anyway I'd better stop rambling and get back to work.
Kind regards
Andrew

 

[Paul Boyd]

Hello Tony
You may indeed regret it because whilst my son is a mathematician and computer programmer, he didn't get those two abilities from me, for sure, as I have some very basic mental blocks about maths that I've never really got over since school. An example being "how can -2 plus -2 = +4". Another is, if I have one of something, and multiply it by zero it then equals zero. To my mind, if I have an apple in my hand multiplying it by zero doesn't magically make it disappear!

Hi Andrew

You sound like a "mathematician" after my own heart, so rest assured you're not alone! My mind also blanks when strange squiggly symbols start appearing accompanied by odd letters, with the word "therefore" as if it's obvious! It's clearly not genetic as neither of my parents are any good at maths, yet my brother has a 1st class honours degree in the subject!

Cheers,
Paul

 

[Tony W]

Hello Tony
You may indeed regret it because whilst my son is a mathematician and computer programmer, he didn't get those two abilities from me, for sure, as I have some very basic mental blocks about maths that I've never really got over since school. An example being "how can -2 plus -2 = +4". Another is, if I have one of something, and multiply it by zero it then equals zero. To my mind, if I have an apple in my hand multiplying it by zero doesn't magically make it disappear!


Kind regards
Andrew

Hi Andrew.

You are getting a bit mixed up here. -2 plus -2 = -4. Adding two negative numbers together creates a greater negative number.
Similarly +2 times -2 = -4, however -2 times -2 = +4 as multiplying two negative numbers together cancels the negatives out. Something I haven't had to think about since my college days. Some things just have to be defined the way they are for the system to work, but are as you say, are difficult to comprehend subjectively. For instance you can't physically possess -2 apples.
The concept of 0 is an interesting one as it impiles the abscence of anything and early maths existed without it. It is a basic rule of maths that multiplying anything by 0 is 0 by definition. Applying this to real world objects as you have just done in your example just causes confusion. This was the rational behind the millennium bug with the year 2000 being shortened to 00 by some computer programs, but I couldn't think of any reason why one would want to divide anything by the date, so wasn't suprised when it turned out to be a non-event.

Being a non DCC person, I have not had to deal with CV settings, so can't really comment I'm afraid.

Regards
Tony.

 

[AndyB]

It's a pity most of us don't have twelve fingers. Twelve is a much more useful number than ten (although it would still be represented as "10" ) Twelve has factors of 2, 3, 4 and 6 while ten only has 2 and 5.

 

[Phil O]

A few of us had to learn to work in 12s and 20s when we were younger in the pre-decimalisation days when there 12d to the shilling and 20 shillings to the pound. I couldn't get my head around guineas 1 pound 1 shilling. Also 12 inches to the foot.

 

[Martin Wynne]

Thanks for the history lesson Martin. Do you mean that all the stuff around 8 bits such as 16, 32 and 64 bit computers, the RAM sizes are all down to Intel's fascination the number eight?

Hi Andrew,

By coincidence, Intel chips are in the news today:

https://www.bbc.co.uk/news/technology-56512430

cheers,

Martin.

 

[AndyB]

Hi Andrew,

By coincidence, Intel chips are in the news today:

https://www.bbc.co.uk/news/technology-56512430

cheers,

Martin.

The last chip I was responsible for before I retired was actually a joint development between our company and Intel. I got to spend a lot of time in Arizona. Our engineers and the engineers from Intel completed the design before the lawyers for the two companies came to an agreement on the financial/legal terms

 

[Jim Guthrie]

A few of us had to learn to work in 12s and 20s when we were younger in the pre-decimalisation days when there 12d to the shilling and 20 shillings to the pound. I couldn't get my head around guineas 1 pound 1 shilling. Also 12 inches to the foot.

I remember doing all the multi-base arithmetic at primary school - Pounds, Shillings (Base 20). Pence (Base 12) was probably the easiest, but Tons, Hundredweights (Base 20), Quarters (Base 4) Stones (Base 8 or 2) Pounds (Base 14) Ounces (Base 16) in addition, subtraction, multiplication and division was probably the worst, or maybe Miles, Furlongs (Base 8), Chains (Base 10), Yards (Base 22), Feet (Base 3) and Inches (Base 12) - all at a pre-teen age. I remember getting fussed about working in Base 2, Base 8, Base 10 and Base 16 when I started working with computers until I remembered what I did as a child.

Jim.

 

[Tony W]

A few of us had to learn to work in 12s and 20s when we were younger in the pre-decimalisation days when there 12d to the shilling and 20 shillings to the pound. I couldn't get my head around guineas 1 pound 1 shilling. Also 12 inches to the foot.

Hi Phil.
Me too. 3 feet to a yard, 22 yards to a chain etc, but it didn't do much to help my mental arithmetic.
Regards
Tony.

 

[Tony W]

I too was taught in imperial measures, Foot, Pound, Seconds (FPS) up to mid way through my secondary schooling when it all changed to CGS (Centimeter Gram Seconds) to O level. For A level it changed to MKS (Meter, Kilogram, Seconds) Time being the only thing they couldn't metricate. Part way through it changed again to SI units, with the result that when I left college I reverted to Imperial measures for many years as I just found the whole damn metric thing confusing and these days I tend to use measures such as 40 thousands of an inch to the millimeter.
Isn't it wonderful what education can do?

Regards
Tony.

 

[AndyB]

I went through all the same metrication steps Tony, and then I had to revert back to Imperial Units when I moved to the US

I only found out recently that a US fluid-ounce is a different quantity from a UK fluid-ounce. It makes it quite tricky to calculate MPG figures for comparison.

 

[Andrew Duncan]

Hi Andrew

You sound like a "mathematician" after my own heart, so rest assured you're not alone! My mind also blanks when strange squiggly symbols start appearing accompanied by odd letters, with the word "therefore" as if it's obvious! It's clearly not genetic as neither of my parents are any good at maths, yet my brother has a 1st class honours degree in the subject!

Cheers,
Paul

Hello Paul
Thanks for your answer, and your support. I often feel like I'm the only person left in the world who has such basic problems with maths and as you can see from Tony's answer, kind and patient though he always is, I've even got what I thought to be true , false! But I comfort myself with the thought that we all individually bring different things to the party, clearly a memory of the mysteries of maths isn't one of mine! As to genetics, I wonder if these things skip a generation or two perhaps?

Kind regards
Andrew

 

[Tony W]

Hi Andrew.
Yes, we all have particular strengths (and weaknesses). You are obviously good with percentages, something many people struggle with. Although we are taught a great deal during our education, precious little of it gets used subsequently. Of all the maths I was taught, after addition and subtraction, it is basic trigonometry I use most, although Templot does most of this for us when it comes to the track side of things. Much else is long since forgotten. One qualification I have is using mechanical calculating machines, which rapidly became totally useless of course.
Regards
Tony.

 

[Tony W]

I went through all the same metrication steps Tony, and then I had to revert back to Imperial Units when I moved to the US

I only found out recently that a US fluid-ounce is a different quantity from a UK fluid-ounce. It makes it quite tricky to calculate MPG figures for comparison.

Hi Andy.
Not just the US fluid-ounce, I believe the US Gallon is smaller than the British Gallon and the US ton is also different.
I remember my Father who was a purchasing manager having to be very careful when ordering materials as the British ton is 2240 lb, whereas the US ton is 2000 lb, then there is the metric tonne which is 2204 lb.
A recipe for confusion if ever there was one.
Regards
Tony.

 

[Martin Wynne]

Don't forget the Baker's Dozen.

Martin.

 

[Andrew Duncan]

Hi Andrew.

You are getting a bit mixed up here. -2 plus -2 = -4. Adding two negative numbers together creates a greater negative number.
Similarly +2 times -2 = -4, however -2 times -2 = +4 as multiplying two negative numbers together cancels the negatives out. Something I haven't had to think about since my college days. Some things just have to be defined the way they are for the system to work, but are as you say, are difficult to comprehend subjectively. For instance you can't physically possess -2 apples.
The concept of 0 is an interesting one as it impiles the abscence of anything and early maths existed without it. It is a basic rule of maths that multiplying anything by 0 is 0 by definition. Applying this to real world objects as you have just done in your example just causes confusion. This was the rational behind the millennium bug with the year 2000 being shortened to 00 by some computer programs, but I couldn't think of any reason why one would want to divide anything by the date, so wasn't suprised when it turned out to be a non-event.

Being a non DCC person, I have not had to deal with CV settings, so can't really comment I'm afraid.

Regards
Tony.

Hi Andrew.
Yes, we all have particular strengths (and weaknesses). You are obviously good with percentages, something many people struggle with. Although we are taught a great deal during our education, precious little of it gets used subsequently. Of all the maths I was taught, after addition and subtraction, it is basic trigonometry I use most, although Templot does most of this for us when it comes to the track side of things. Much else is long since forgotten. One qualification I have is using mechanical calculating machines, which rapidly became totally useless of course.
Regards
Tony.

Hello Tony
Thanks for your patient explanations of where I was going wrong / getting confused. There's probably not a lot of hope for me on that score, which may well be because even if I were to multiply two minus figures together, that in mathematics become a positive, for me they'd remain negative. Admittedly I can't think of a scenario in my business where I'd ever do this?
So I suppose my sort of maths is basic and always to do with the tangible, I cant have minus 3 saucepans!

The problem with education I think, is that it's a "one size fits all" approach, bound to fail for a number of us I think and I, to state the obvious, was one of them.

Kind regards
Andrew

 

[Tony W]

Hello Tony

So I suppose my sort of maths is basic and always to do with the tangible, I cant have minus 3 saucepans!

The problem with education I think, is that it's a "one size fits all" approach, bound to fail for a number of us I think and I, to state the obvious, was one of them.

Kind regards
Andrew

Hi Andrew.
You appear to have done well enough in spite of it.
Regards
Tony.

 

[Andrew Duncan]

I remember doing all the multi-base arithmetic at primary school - Pounds, Shillings (Base 20). Pence (Base 12) was probably the easiest, but Tons, Hundredweights (Base 20), Quarters (Base 4) Stones (Base 8 or 2) Pounds (Base 14) Ounces (Base 16) in addition, subtraction, multiplication and division was probably the worst, or maybe Miles, Furlongs (Base 8), Chains (Base 10), Yards (Base 22), Feet (Base 3) and Inches (Base 12) - all at a pre-teen age. I remember getting fussed about working in Base 2, Base 8, Base 10 and Base 16 when I started working with computers until I remembered what I did as a child.

Jim.

It's funny Jim, but when you put it like this (eg ounces, pounds, and stones all being different bases) it seems so much less threatening and mysterious. Suddenly I can relate to it, because its familiar and what I grew up with!

Andrew

 

[Martin Wynne]

So I suppose my sort of maths is basic and always to do with the tangible, I cant have minus 3 saucepans

Hi Andrew,

Of course you can -- it means you have 3 customers waiting for a saucepan and none in stock.

If they are waiting to boil an egg, they have my sympathy.

Martin.

 

[Andrew Duncan]

Hi Andrew.
You appear to have done well enough in spite of it.
Regards
Tony.

Nice of you to say so Tony. What I'm happy to admit to is having had more than my fair share of good luck and particularly in the last 20 years or so, setting out to teach myself or find someone to teach me what I didn't know. Although that in fact, I found that quite hard simply because I often didn't know what I didn't know. That's not meant to sound as glib as it does, but for a number of years, not knowing where to turn, stopped me from developing myself because I didn't know what sort of help to look for or where to find it.
Perhaps the biggest luck was in inheriting a business from my parents that I just loved, and still do for that matter.

Andy, sorry for the divergence from the topic of quiet environments for servos. I will now shut up!
Kind regards
Andrew

 

[Andrew Duncan]

Hi Andrew,

Of course you can -- it means you have 3 customers waiting for a saucepan and none in stock.

If they are waiting to boil an egg, they have my sympathy.

Martin.

There's me, lacking imagination again Martin. shall try to do better next time!