an Oil-Tank Monitoring puzzle : Domestic Heating

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Nicely concise answer, Bantam Bill

I will show my working later, but I ended-up with 2420

MichaelG.

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Edit: __ but first, a little digression: This is why I am getting double posts

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The funny thing being that if I just ignore it and refresh the forum page, my post is there.

Edited By Michael Gilligan on 28/11/2022 14:09:13

O.K. here we go …

The first obvious problem is the presentation of the ‘switch setting chart’, which serves only to obfuscate a simple table … so I put all the values into a simple spreadsheet.

Then we note that Switch_1 serves a special purpose, and is not relevant to the height of the tank.

The pattern [clearly visible when the settings are neatly tabulated] is simple binary.

So … assign values to each of switches 2 to 8 and add them up for each row

Then notice that the sums contain those Red Herrings that I mentioned !!

Now leap to the obvious conclusion that the list of heights has been fudged for ‘cosmetic’ reasons … they don’t really increment by 50mm, but the whole hundreds work.

The value in my column L is always 500+(20x the value in colum K)

… As presented here I have left the 40mm increments blank

The bottom line is that 1100000 = 96

and 500+(20x96) = 2420

So my empty tank was showing approximately half full.

Having set the switches appropriately, it now reads empty and I am sitting here waiting for a delivery of oil.

Brrr !!

MichaelG.

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I assumed it was binary and that a fudge factor had been included in the table, but I just took an educated guess at the value. It reminds me when I was trying to program my inverter and struggled to work it out but got it in the end.

Basically you have to create a 9 bit binary number and convert it to hexadecimal and enter that into the VFD. in my case I wanted to change the polarity of terminal S4 which is bit number 3 so:-

Bit number 8 7 6 5 4 3 2 1 0

Bit setting. 0 0 0 0 0 1 0 0 0

Convert 0 0 0 0 0 1 0 0 0 to hexadecimal (that’s easy use a converter from the interweb) = 8

Entered 8 on the VFD, result it works.

Suppose you wanted to change the polarity of all terminals, the binary number would look like this:- 1 1 1 1 1 1 1 1 1 The hexadecimal is 1FF which is what to enter in the VFD, also hexadecimals are usually prefixed with 0x so it should be written as 0x1FF.

Edited By Bantam Bill on 28/11/2022 16:03:04

Edited By Bantam Bill on 28/11/2022 16:13:01

It may not be the settings I once had a problem with a large tank and incorrect level readings, I could see the echo trace on my lap top and it showed two return echos. One was from the surface of the liquid The other which was the larger, was from the surface and then was being reflected from the top of the tank, back to the surface and then to the transducer. The top of the tank was a wonderfull reflector.

I have had the same type of problems with radio signals where a reflection from a hanger door been moved became stronger than the signal that I was using to check the kit I was working on.

Dave

Ah, I see now what you were asking. You asked "what does it (1,2,3) do", but what you meant was, 'what tank volume does 1,2,3 test for.?'.

[ UPDATE ]

I doubt this will come as any surprise to those that followed the logic … but it’s worth mentioning in case anyone ever visits this thread in the future:

As mentioned above: Having set the switches appropriately, the Apollo correctly read empty

This morning, 500 litres of oil were dispensed into the 1,000 litre tank, and the Apollo is reading half full.

… and they all lived happily ever after.

[ or at least I will be warm enough to be able to think about what to do next ]

MichaelG.

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Well, yes … if you prefer to put it that way

Alternatively the answer to my question could be

“it sets the ‘low level audible warning’ function, and a useable tank height of 2420 mm”

[ noting that tank volume remains unknown ]

MichaelG.

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Pedants of the World unite !!

Edited By Michael Gilligan on 29/11/2022 10:18:47