# 4-20mA Output current

#### MihirGogri

Joined Feb 10, 2020
14
Hi,
In my project i am using accerelometer which is giving me output in the form various voltages. I want to send this voltages to other circuit which is kept 10 metre away. But the problem is the voltages will not travel such distance, so I have used XTR111 ic to convert this voltages to current. On testing this setup with 1-2m wires the current is proper but on oscilloscope it's showing noise, What can be done to get a clean signal?
P.S- For current to voltage conversion I am using RCV420, which is not giving me proper voltages.

#### ericgibbs

Joined Jan 29, 2010
15,332
hi MG,
Do you have a circuit to post showing the details of the Load resistor used to terminate the 20mA loop at the receiving end.?
What is the noise level etc.?
E

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#### strantor

Joined Oct 3, 2010
5,907
On testing this setup with 1-2m wires the current is proper but [...] For current to voltage conversion I am using RCV420, which is not giving me proper voltages.
How do you know the current is correct then?
. On testing this setup with 1-2m wires the current is proper but on oscilloscope it's showing noise, What can be done to get a clean signal?
Where are your probes as you measure this noise? The good thing about 4-20mA is its noise immunity. It can have "noise" on the line without noise in the signal transmitted, because the noise does not generate any current.

#### crutschow

Joined Mar 14, 2008
29,466
Your oscilloscope it likely grounded and measures the voltage not the current, which can have noise.
To detect the 4-20mA signal, you need a current sensor that does not ground the signal.

#### MihirGogri

Joined Feb 10, 2020
14
How do you know the current is correct then?

Where are your probes as you measure this noise? The good thing about 4-20mA is its noise immunity. It can have "noise" on the line without noise in the signal transmitted, because the noise does not generate any current.
i have attached ammeter in series. one end is connected to the output of the xtr ic and other to 250 ohm resistor.

#### crutschow

Joined Mar 14, 2008
29,466
i have attached ammeter in series. one end is connected to the output of the xtr ic and other to 250 ohm resistor.
How are you measuring noise with the ammeter?