Loop Powered 24VDC 4-20mA signal

Hi
I have an existing 24VDC power supply that I would like to tap into to draw 0.2 amps from. However the power supply is currently being used to
provide the power supply for a 4-20mA loop powered signal (back to a PLC input).
I am trying to think of any reasons why I couldn't use this power supply - ie tap into it in parallel. The power supply has spare capacity.
Thanks in advance
Ethean
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On 12 May 2005 01:40:53 -0700, the renowned "Ethean"

If you're running a dirty switching regulator you may inject noise into the signal (depending on the design of the transmitter and the PLC input filter).
Be sure to check for any grounding issues.
Other than that it should work.
Best regards, Spehro Pefhany
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Hi
I agree with Spehro.
Regards,
U.
"Poor is the pupil who does not surpass his master" -- Leonardo.
du: snipped-for-privacy@4ax.com...

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Thanks Spehro
By grounding issues do you mean if the 4-20mA signal is powered by a floating supply?
cheers
Ethean
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On 15 May 2005 03:46:19 -0700, the renowned "Ethean"

The supply and everything connected to it-- should have at most one ground (including sneak paths through non-isolated transmitters and grounded sensors).
Best regards, Spehro Pefhany
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snipped-for-privacy@interlog.com Info for manufacturers: http://www.trexon.com
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Basically we do not mix 4-20 mA signals with other signals or electrical components in the plant.
The reason is simple, you may introduce noise in the 4-20mA and this will cause problems in your process control
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snipped-for-privacy@gmail.com wrote:

He didn't ask about mixing signals. He asked about sharing a power supply. If ground considerations permit it, good bypassing should make it feasible. It's an amateur (or emergency) thing to do. The cost of an extra supply is far less than the cost of an hour's down time.
Jerry
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Engineering is the art of making what you want from things you can get.

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Sorry I did not mean to mix signals, anyway just to make myself clear. In our projects we provide two different power supplies: one for digital points, one for analog points. Therefore we do not have one single power supply to everything.
I agree with you when you say " The cost of an extra supply is far less than the cost of an hour's down time. "
Flvio
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Thanks guys
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