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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32 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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10answers
3k views

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
75 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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77 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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1answer
35 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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87 views

DAC7760 voltage and current output

I use the following function to send data from STM32f1 to a DAC7760: ...
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1answer
102 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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302 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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3answers
96 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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44 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
136 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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127 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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65 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
140 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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33 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
89 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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71 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
198 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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81 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
176 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
387 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
48 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
565 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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2answers
313 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
793 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
365 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
207 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
357 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
166 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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128 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
428 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
1k 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
123 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
2k 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
345 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
1k 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
129 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
133 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
514 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
397 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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763 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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222 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
270 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
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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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164 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
15k 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
344 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
697 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 ...