Questions tagged [4-20ma]

In industrial environments 4-20mA is a commonly used range of values for a current loop where 4mA represents the lowest value and 20mA indicates the maximum. Some advantages compared to sending a voltage is that the resistance of the cable doesn't affect accuracy and devices may be powered from the same pair of wires.

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3answers
84 views

Is a current varying output or voltage varying output for a 4-20 mA sensor more reliable for a rocket?

For the internal plumbing system of a rocket which is expected to reach 100 km above the ground, industrial pressure sensors with a 4-20 mA current output and a 0-10 VDC output are available. What ...
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26 views

Common ground b/w power supplies and analog pin for microcontroller

Referring to the schematic below, is it best practice to have the 5 V supply on the right powering the MC (arduino-esque microcontroller) share a common ground with the 24 V supply ? The 24 V supply ...
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1answer
54 views

What happens when a 4-20mA sensor is connected in reverse to receiver?

simulate this circuit – Schematic created using CircuitLab I need to build a 4-20ma to 1-5v converter circuit. I have a working model with a 24v supply and a 250 ohm resistor. Now I need to ...
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68 views

measure 4-20 mA and also power from loop powered

we know to give a command to an actuator in instrumentation we use 4-20 mA loop power. for reading this 4-20 mA I used the circuit below.so the problem is if my circuit only consumes 3mA, how should ...
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1answer
58 views

Conversion 0-20mA to 0-5V [closed]

Have you ever used this device? https://fluxworkshop.com/products/biaa100070-lm358-a2v-20ma-5v-lc-blue I have prepared a circuit as follows. I have used a distance sensor. Unfortunately, I obtain a ...
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1answer
72 views

Trouble using a generic 4-20mA to 0-5V board to connect transmitter to Arduino

I'm doing a big project, where I will connect a lot of sensors to my Arduino Mega 2560. Eagerly, I bought boards of this type, but I can't get them to give me any voltage output! I've connected them ...
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29 views

Current Controlled Potentiometer

The core problem I am having is that I need to be able to control a DC to DC voltage regulator based on input from a 4 to 20 mA signal. The end goal is to have the output voltage of this regulator be ...
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3answers
48 views

Current loop measurements with MCU

I want to measure currents in range between 4-20 mA. Could you tell me whether this circuit is good for this operation. I'm using an ADC 3.3V in a microcontroller (thus, I receive voltages in range ...
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1answer
52 views

AC/DC power supply module with 20mA output current

i want get 20mA current with 24V ac to dc. I have found this power supply module with 6-9A output current but i need max 20mA. What can i add with this module to achieve my settings? I am powering ...
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2answers
102 views

Several Questions About Analog Input

I am new in the automation industry, and now I am focusing on learning how to wire correctly analog inputs in detail, since last time I tried I damaged the module input because of wrong wiring. Here ...
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74 views

4-20mA current loop - transmit sensor reading

I am working on design loop current transmitter- to transmit reading value from thermocouple sensor using below design. I measured co-junction temperature using NTC instead of RTD. During applying ...
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1answer
82 views

Issue having 4-20 mA interface with ADS1115

I need to make a 4x 4-20mA measuring circuit with ads1115 (VDD = 5V) 4 channel 16bit ADC I set ads1115 PGA to 4.096 gain and set circuit as below. once I set this 32000 ADC levels--> 4.096V--> 0....
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1answer
193 views

Designing voltage to current converter 4-20 mA [closed]

I'm currently designing (or at least trying to) a RTD amplifier with ICL and current outputs. What I've got so far is a working RTD and ICL schemes, but I still struggle to design a proper converter....
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2answers
40 views

Nmos trigerring in 4-20mA converter

Here is the circuit I am trying to understand: It comes from the following application note from LT: https://www.analog.com/media/en/technical-documentation/technical-articles/D61_EN-Convert.pdf I ...
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0answers
293 views

4-20mA with 12V sensors using ADS1115 ADCs

I am currently designing a 4-20mA current loop with external sensors which work at 12V DC. I saw a differential application on the datasheet of the ADS1115 ADC, but the simple shunt resistor I believe ...
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1answer
24 views

Help identifying proper connection of pressure transducer?

I am using a US381-0000005-100PA pressure transducer. The datasheet. The '8' indicates its the 5-20 mA current loop type. The transducer has four wires - red, white, green, and black, but the diagram ...
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2answers
215 views

fluctuating ADC Reading for 4-20mA Pressure transducer input

I am working on one project of water pressure measurement, in which i used pressure transducer which gives me output between 4-20mA Current form. I am using one 250 ohm resistance to convert current ...
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1answer
411 views

4-20mA current loop design

I have been working on 4-20mA transmitter project and stuck with a problem. My design is based on CN0319 evaluation board but I changed some of it, to make it works with other part of the design. ...
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2answers
238 views

4-20mA loop voltage to high

I have a 0-16 bar pressure probe connected to a module called Adca UD-720. The probe works on a 4-20 mA loop and the readings are ok. This module also has a 4-20 mA output and I need to connect this ...
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2answers
129 views

Current loop protection from wrong connection of the wires

I have built a current loop protection circuit based on the topic Using a microcontroller ADC to measure a 4-20mA sensor It works good. The next step is I want to protect the input of the circuit ...
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1answer
274 views

4-20 mA sensor with logarithmic scaling

We have a liquid conductivity sensor/meter that can be configured to output its sensor value encoded onto a 4-20 mA current loop. The meter has options of outputting the 4-20mA loop as a linear scale ...
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2answers
140 views

How the does this circuit source 4-20mA?

In the circuit, how the mosfet flow the 4-20mA based on the resistor network?
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1answer
106 views

Interface Self power Sensor with Particle Photon using 4-20mA current receiver

Is it possible to use 4-20mA self powered sensors using current receivers ? If not then what will be the best way to use these sensors and interface it Particle Photon to monitor the readings? Note:- ...
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3answers
310 views

Analyze of 4-20mA circuit

I'm looking at the 4-20mA circuit below and trying to understand it. For some reason I can't get this to click in my mind. Pressure sensor is a Metallux ME751 with a supply voltage of 9..35 VDC and ...
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4answers
693 views

how to get 4-20mA output

i test the below circuit using with LM358. and i use instead of n-MOSFET i use CL100 transistor and for p-MOSFET i use CK100. in my 4-20mA converter circuit for 1.1 v input i get 31mA and for 4.4v ...
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1answer
111 views

Fluctuating ADC readings upon changing power source

I used the following circuit to power and measure my pressure transmitter (4-20ma) sensor and the microcontroller, when the charger and battery are connected at the same time or when i disconnect the ...
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3answers
965 views

Arduino 4-20mA transmitter

Looking to build an Arduino controlled current-loop transmitter for driving 4-20 mA over an ~100 Ohm non-inductive resistance with 24V power supply. Also the Arduino should drive ideally 4 independent ...
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2answers
280 views

4-20 mA loop powered ADC with display

I was asked to design a display that is loop powered and sits between the receiver and the transducer. I was wondering what's the best way to source power from the loop to power my electronics without ...
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2answers
384 views

Splitting a 4-20mA signal to two separate data loggers

I am wanting to read a single 4-20mA signal from a water meter on two separate data loggers. I need help on the wiring in order to split the signal to the two loggers. The first logger is a Campbell ...
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1answer
122 views

Drive 6Vdc relay ( with coil resistance 68ohms ) with 20mA current source

I have a current source of 4-20mA and I need this to drive a 6Vdc relay. I could not use passive Current to Voltage converter since the relay coil have resistance of 68 ohms and the voltage drops at ...
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2answers
103 views

ADC input software multiplexed between current/voltage input

Problem I need to design an isolated analog front end to a Raspberry Pi which needs to work with either a 4-20mA or 0-10V transmitter. I've been studying existing analog input modules from major PLC ...
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1answer
377 views

Measuring 4-20mA current using the 4 20ma R Click module

I have a 4-20mA Receiver click module hooked up to a 5V Arduino. The goal is to have this system be able to measure 4-20mA current. I'm using a simple resistor - LED circuit for testing, as well as a ...
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2answers
289 views

4-20 mA power loop with single source (pressure probe) and three receivers (controllers)

First of all, I am mechanical engineer, not electrical, so please forgive me for possibly silly question. I need a help connecting a single 4-20 mA source to three receivers. The source is pressure ...
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2answers
628 views

How do 4-20 mA receivers work?

For a sensor device such as a positioner, do they sense 4-20 mA from two wires and supply from another two wires, or is this done with only two wires? If only two wire, how can I do this?
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1answer
192 views

Raspberry Pi hat design

I am designing a Raspberry Pi hat that needs to be able to accept inputs from 3 different water meters. Two of the inputs are 4-20mA signals, the third input being a pulse signal. At the top I have ...
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2answers
139 views

Two 4-20 mA masters/readers for one sensor

I need to read the value of a 4-20 mA sensor, however I need to not interrupt the existing equipment that is already running. I have a plc that monitors a 4-20 mA pressure sensor. I need to build a ...
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4answers
1k views

Need more current than 4 mA in 4/20mA loop current

We know that in a 4/20 mA loop current, 4 mA represent 0% and 20 mA represent 100%. For loop current we use an IC like XTR115, and my circuit is fed from this IC. If my circuit needs higher current ...
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1answer
144 views

About the solution EMC/EMI of AD421

We are using to the AD421 parts on our industrial products and we are testing the EMC/EMI test for getting certification. I'm trying to find the root cause about surge(IEC61000-4-5)/burst(IEC61000-4-...
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6answers
12k views

4-20mA Output from Arduino

I want to control an industrial motor rate valve that accepts a 4-20mA input. I want to use Arduino Uno as the controller of such a device but I do not know how to generate such signal from Arduino. ...
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3answers
1k views

Amplify current from a 4-20 mA temperature controller to drive a Peltier module

I have a temperature controller (Chino DB1000) which has a PID output of 4-20 mA. With this, I want to control the current going to a Peltier thermoelectric module (15V, 6A). I am doing this via an ...
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1answer
273 views

measuring analog current output with beaglebone

I'm thinking about using a BeagleBone to measure the flow-rate of a fluid through a pipe. Here is a breakdown of the scenario: this flow sensor could be used from the doc, the output is a 4-20 mA ...
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1answer
534 views

4-20mA Current Loop - Multiple Sensors

As of now, I have a fairly good understanding about the 4-20mA current loop standard. It needs, of course, a sensor with either 2-wire or 3-wire output 4-20mA (4mA as zero reading and 20mA full-scale ...
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3answers
1k views

1-5V to 4-20mA voltage drop problem

I'm hoping someone can help me remedy this problem (or at least come up with a temporary solution), as I am a novice in electronic circuits. The below circuit shows my setup. Vin is my input signal ...
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1answer
1k views

How does this circuit read 4-20mA current loop input through Op-amps?

I am a software guy working on coding a control system on a board whose hardware designers are all gone. While i have got everything else working, there is one piece (a 4-20 mA current loop ...
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1answer
63 views

Continous liquid level measurement loop connection device

I have 4-20mA loop device for measuring liquid levels. It was working well until I connected a motor (heavy load) to the same outlet(120Vac). I have this device ON and as soon as motor turns ON the ...
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1answer
772 views

Protecting 0/4 - 20 mA loop from over voltage/current?

I'm building a device to read 0/4 - 20 mA loop currents using a 250 ohm precision sense resistor. The power source inside the receiver used for driving the sensors is current limited to 30 mA. Suppose ...
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1answer
364 views

DAC Output to 4-20mA [duplicate]

I have a Microcontroller with a DAC output of 0-3.3V. What external circuitry can I use to convert it into a 4-20mA current transmitter.
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1answer
187 views

Hooking up a 4-20mA current output directly to a scope or a DAQ?

I have a sensor which outputs both voltage and current optional. But the current output is recommended for less than 500 Ohm in data sheet. I'm afraid if someone just hooka up this current output ...
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2answers
445 views

4-20mA Error vs Distance Relationship [closed]

Is there a relationship between noise error and distance for 4-20mA? This noise error could be expressed as S/N ratio, percent from full range, dynamic range, noise density, resolution, etc. Digital ...
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2answers
730 views

How do I convert voltage square wave signal to 4-20mA signal

At school we are looking for a sensor that is able to count/sense the rpm that the shaft is turning at. I have found a sensor which does this but it sends out a voltage square wave: Datasheet I need ...