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Guest rjenkins

Alarm installation - cable type query

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And Georg - cable length is directly proportional to where you cut it! :)

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And Georg - cable length is directly proportional to where you cut it! :)

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:roflmao:


Service Engineer and all round nice bloke :-)

The views above are mine and NOT those of my employer.

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Guest
:roflmao:

45245[/snapback]

hmm.. i think i missed to think something...???????

That would mean that I just learned something.. :blink:

(never had to think relationship between NVP and capasitance)

IF I learned something it would mean that different conduits (ie copper vs aluminium) will have different capasitance. Nothing thou rings the bell in my head that formula of capasitance would consist of the conductivity of the conduit..

:question:

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But capasitance depends also of cable lenght and is usually announced as pF / 1km .
Their are MANY other factors that determine CAPACITANCE Georg.. But I`d really like to know why you want to how to measure it..?

........................................................

Dave Partridge (Romec Service Engineer)

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Their are MANY other factors that determine CAPACITANCE Georg.. But I`d really like to know why you want to how to measure it..?

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Thanks Dave,

I really felt lost while spelling CapaCitanCe in my mind.. :lol:

How to measure? With a capacitance meter of course..

Why so important? Because it causes a squarewave signal to look like a sinewave signal and that isn't good for data transmission..

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Hmmm Short runs use RS232, long runs use RS422.

I`d like to know at what point you would consider the capacitance too high..?


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Dave Partridge (Romec Service Engineer)

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Hmmm Short runs use RS232, long runs use RS422.

I`d like to know at what point you would consider the capacitance too high..?

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or RS485 (thou i don't have a slightest idea of difference between 422 and 485)..

I would also be interested of the knowledge when capacitance is too high.. :lol:

But obviously it is too high if data isn't going through.. :yes:

I think it is calculatable of speed of data and maximum desired cable length (therefore NVP..???? )

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LOL Georg, you`ll be rambling on about FM and FSK next... :roflmao:


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Dave Partridge (Romec Service Engineer)

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LOL Georg, you`ll be rambling on about FM and FSK next... :roflmao:

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I know only basics of freguency modulation and i hate frequency shifting key already since we are trying to make normal modem to understand it with one blondshirish colleague.. :lol:

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A VERY handy and informative site for anyone interested in CIRCUITS..

All About Circuits..


........................................................

Dave Partridge (Romec Service Engineer)

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A VERY handy and informative site for anyone interested in CIRCUITS..

All About Circuits..

45291[/snapback]

hmm.. a bit simple but good start indeed. simplicities are very well explained.

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