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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35 views

pt100 RTD transmitters not working - two in a row - am I doing something wrong?

I just tried to use two different ones of these RTD transmitters with a pt100 probe (3 wire) with no success. I am connecting the transmitter directly to a 4-20mA input on a PLC, as shown in the ...
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39 views

Where to properly terminate 4-20mA cable shield in ungrounded low voltage DC system?

Preface: I read both: ungrounded chassis shielding and: RS485: Where to connect the cable shield in a battery-powered system? A sensor system I'm working on is getting installed in a 20x20' cement ...
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82 views

Can 4-20mA transmitters send through a 1kOhm resistor?

I have a 4-20mA sensor at work and I wonder if it's possible if a 4-20mA transmitters send through a 1kOhm resistor? I guy I talked to said that 4-20mA normaly can't send through 1kOhm because it's to ...
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49 views

Frequency Key Shift technique to superpose the digital communication on top of 4–20 mA signals

I start working with HART devices and I really try to understand how digital data is transferred trough 4-20ma current loop. I start read this article: https://instrumentationtools.com/hart-...
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174 views

circuit for converting in 0-5v to 4-20mA current source

basically is want to make a circuit that takes 0-5v input and converts it in and corresponding output current of 4-20mA using opamp , i have seen reference circuit from this pdf https://www.analog.com/...
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31 views

LTSPICE time step to small for (0-5V) to (4-20mA) converter

i am trying to simulate a (0-5v) to (4-20mA) coverter circuit .when i am trying to the transient analysis of the circuit in the Ltspice i getting a time step error i have kept stop time as 100 for ...
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28 views

VIH of digital selection inputs for analog Mux when supplied with 4096mV - CD4051 IC

I will use CD4051BM96 part number, DATASHEET On page 7 is shown specs of VIH. It shows VIH of 3.5V for 5V supply (this 70% of VDD), VIH of 7V for 10V supply (70%) and VIH of 11V for 15V supply (73.3% ...
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38 views

Automotive Sensor Output

Why does the automotive industry sticks with 5V sensor outputs instead of something like 4-20 mA? Wouldn't it be a solution less prone noise? What are the advantages in using a 5V output instead of a ...
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30 views

Designing signal conditioner to convert current source to voltage output

I've seen a lot of signal conditioners online for converting a 4-20 mA current loop signal to a 0-10 voltage output. However, they seem extremely expensive for the task they are achieving. Are the ...
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43 views

Measuring 4-20mA with differential ADC

I have a question. Is it a good way to measuring 4-20mA with differential ADC? Assume that we have a ADC with 2 single ended inputs or 1 differential input. Input A+ is the first input and input A- is ...
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77 views

ADC Input Protection with 4-20mA

If you've got a 4-20mA transducer, powered by 14V, and you want to measure it, your analog front end might look something like this: simulate this circuit – Schematic created using CircuitLab .....
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46 views

Battery powered 4-20mA sensing application

I have a base system that runs on 3-AA batteries which it regulates to a system voltage of 3.3V. I want to interface that system to measure a 4-20mA sensor. For the sake of argument, lets say that ...
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2answers
76 views

Converting a 4-20mA 24V signal to 0-5V?

How do I convert a 4-20mA 24V signal to a 0-5V signal, suitable for A-D conversion with a 5V microprocessor? Can this be done while isolating the 24V from the 5V output?
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4-20 mA PID controller PCB Layout

I have designed a 4-20 mA PID controller using atmega 328p, MCP4922(DAC), XTR115UA(4-20 mA current loop transmitter) I used the circuits proposed in datasheets and the PCB and schematic files are ...
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208 views

4-20mA output from Arduino Nano

To convert 1-5V to 0-20mA: When I use 3.3V ouput from Arduino Nano Power Pin--> Iout = 13mA (which is ok). Similarly, with 3.3V Battery -> Iout = 13mA (which is ok). But, when I use 3.3V ouput ...
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1answer
205 views

4-20 mA output from Arduino for VFD

I'm a beginner with electronics, so everything has to be explained in simple terms to me. I have an Arduino with a program which provides a value via the Analog output, so that is anything from 0-5 V....
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Is this an elegant approach for a simple, debounced tank level controller?

I am interfacing some industrial (24v) process control equipment to some new projects in the embedded realm of electronics (3.3/5V small signal) and am coming up with some simple solutions for ...
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1answer
36 views

4-20ma 3 wire linear transducer and arduino connection problem [closed]

I am trying to connect a 24 volt 4-20ma 3 wire resistive linear transducer to arduino with 4-20ma to 0-5 volt converter (https://www.amazon.com/Isolation-Current-Transmitter-Converter-Transformer/dp/...
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74 views

4-20 mA Loop voltage Implementation using XTR115

I want to Implement 4-20mA current loop using this circuit that is proposed in the IC datasheet. I used 7805 regulator to Implement Vloop and this is my Schematics. will this work? Edit: the load is ...
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77 views

Correct way to measure a 4-20mA sensor?

I have an 0-10V analog input channel that I would also like to measure 4-20mA sensors. I have added a 500 ohm shunt resistor I can jumper in when I am using the 4-20mA instead of the 0-10. Can this be ...
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944 views

4-20 mA to 0-3.3V converter

I have a 4-20mA signal and want to feed it to my uC. I found this circuit but dont know how it works. can any one explain this for me? or suggest a better solution
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71 views

4-20mA to switching output

I have a 4-20mA output. I need to turn an LED on when let's say 20mA is reached. I can obviously do this easily with a plc or an Arduino, but I need to do it as cheaply as possible. Is there a simpler ...
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1answer
40 views

ATMEGA 2560 => MCP4725 => FC-33 => Electronic Pressure Regulator

I am purchasing a regulator that accepts a 4-20mA control. I am hoping to interface this to an ATMEGA2560 microcontroller. I am looking at using a MCP4725 DAC driven by the I2C bus of the ...
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Best practice in transmitting sensor analog signal over longer distances (approx. 100') — in cost sensitive products for microcontrollers

I'm looking for best practices for transmitting an analog sensor signal over long distances to a microcontroller such as the Arduino running at 3.3v or 5v. Keeping costs low is imperative. SPI and ...
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2answers
256 views

Controlling a 0-20mA transmitter from an isolated PWM signal

I'm trying to generate a 0-20mA signal for controlling an industrial actuator (the position of a 3-way valve) from a Teensy 3.2 system. Preferably, the mA-output should be galvanically isolated from ...
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1answer
234 views

Voltage controlled current source using op-amps

I have a sensor which gives a voltage output between 0V and 5V. I need to transform this sensor output to a current suited for a 4..20mA current loop. The thing is, the current loop doesn't have a ...
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44 views

4-20mA PLC analog output ground referencing for other devices

I'm currently using a PLC to control an induction heating coil. I'm using a chinese induction driver that allows 4-20mA PID input. This device runs off standard australian 230v AC 50hz. I've ...
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114 views

DAC7760 voltage and current output

I use the following function to send data from STM32f1 to a DAC7760: ...
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1answer
183 views

XTR111 4-20mA to 0-10V issue

I have below circuit which produce 4-20mA and by adding resistor (before the TVS) I can get 50ohm => 0-1V 250ohm => 0-5V but unable to get 0-10V since when I add 500ohm resistor, the voltage max out ...
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804 views

How/can I plug a 3 wire 4-20mA current sink probe into a 2 wire 4-20mA loop powered controller?

I have a 3 wire 4-20mA output probe simulated here, where during normal operation the 20v and 250 ohm resistor are variable chosen by the user. One of my users has a 2 wire 4-20mA meter, and I am ...
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100 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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1answer
106 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
350 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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209 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
73 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
196 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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34 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
142 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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101 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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317 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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92 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
358 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
556 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
55 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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789 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
26 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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4answers
450 views

Fluctuating ADC reading for 4-20mA pressure transducer input

I am working on a project of water pressure measurement, in which I used a pressure transducer which gives me output between 4-20mA current form. I am using a 250 ohm resistor to convert current into ...
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1answer
1k 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
474 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
312 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 ...