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Jeba Keziah
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Join Date: Oct 2009
Posts: 18

Transmitter

01/06/2010 3:47 AM

how can we identify, a transmitter is self powered or loop powered?
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#1

Re: Transmitter

01/06/2010 3:52 AM

If it is loop-powered, it only has 2 wires.

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Jeba Keziah
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#3
In reply to #1

Re: Transmitter

01/06/2010 4:06 AM

But some fuel oil flow transmitter and oxygen analyser are mentioned as 2 wire self powered. How can we identify those transmitters?
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PWSlack
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#4
In reply to #3

Re: Transmitter

01/06/2010 4:23 AM

Read the manuals that come with them.

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Jeba Keziah
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#5
In reply to #4

Re: Transmitter

01/06/2010 4:32 AM

I don't have manual regarding this one. I'm new to the power industry, im a fresher. if u help me, it will be useful to me.
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PWSlack
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Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
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#6
In reply to #5

Re: Transmitter

01/06/2010 5:02 AM

Get on to the suppliers and ask for them, or visit their websites.

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Jeba Keziah
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#7
In reply to #6

Re: Transmitter

01/06/2010 7:22 AM

Thanks for your suggestions.
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craigza
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Location: Johannesburg
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#2

Re: Transmitter

01/06/2010 4:02 AM

Hi there,

This has been answered before.

To make absolutely sure: read the manual. You can also refer to the specification plate on the transmitter.

Some transmitters require external power 100-230VAC, but the signal lines may still be loop powered. (Found in some Khrone Ultrasonic flow meters)

As a general rule of thumb (use at your own peril if you are not going to read the manual): If the transmitter only has two wires, i.e. the signal wires - it is loop powered.

If the transmitter has four wires, i.e. two for signal and two for external power - it is self powered.

Regards,

Craig
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craigza (1); Jeba Keziah (3); PWSlack (3)

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