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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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4-20mA sensor reading

I've designed a schematic for a 4channel 4-20mA input reading circuit utilizing the INA196 IC with an ADS1115 ADC. After simulating the circuit in TINA, it appeared to be functioning correctly. ...
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XTR111 4-20mA/0-10V before mux stage

I am currently designing a PLC-like module based on a STM32 microcontroller. I want to have up to 8 analog outputs generating 0-10V or 4-20mA signal. I am heavily relying on this design by TI: https://...
Sobekurxo's user avatar
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Dual 4-20 mA inputs to voltage ramp

I'm trying to take dual 4-20 mA signals and use them as a heat/cool signal for a Peltier module. I have an integrator but I'm trying to find the best way to decipher the dual signals and turn them ...
Kieran Clifford's user avatar
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1 answer
207 views

Input / Output impedance for 4-20mA signals

Hoping I can gain some clarity on an issue that I am having - We recently installed a new system to running a VFD controlled pump, controlled by a pressure transducer. The pressure transducer we ...
Steven Anderson's user avatar
1 vote
2 answers
150 views

Twisted pair wiring 4-20 mA sensor

I have a pressure sensor with 24 V, GND and 4-20 mA signal output pins. It will communicate with a PLC. I will only use 3m of wire max. for each pin. The installation will be on the rooftop maybe a ...
Gurul_01's user avatar
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3 answers
125 views

DIN rail terminal block resistor

Is there a reliable solution for placing my own through hole resistor into a DIN rail mountable terminal block? Or is there any off the shelf solution the use a resistor to convert my 4-20mA current ...
Gurul_01's user avatar
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3 answers
219 views

4-20mA analog output into a digital input?

I'm measuring the 0-10V pressure output of a pressure sensor with a LOGO! smart relay (PLC). I would like to make sure that the pressure sensor is working even when I'm measuring nearly zero values ...
Gurul_01's user avatar
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26 views

Voltage Offset and Scaling from DAC to current driver

I have a DAC with an output of 0-4.096V that I need to convert to 4-20mA. I am planning to use the XTR111 which converts 0-5VDC to 0-20mA. To use the full range of the DAC (ie 0-4.096V = 4-20mA), I ...
Pribusin's user avatar
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3 answers
292 views

Reading 4-20 mA industrial pressure sensor

I am trying to read an industrial pressure sensor (datasheet) with range 0-10 bar and output 4-20 mA, with an Arduino Opta RS485, powered from an external 12 VDC source. Leaving the sensor in the air,...
p_a321's user avatar
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3 votes
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Purpose of V- of 4-20mA Current Loop

I am trying to use this AFE881H1 as my 4-20mA loop transmitter but I have trouble understanding why they put ground above V-. So at R2, there is a current flowing from ground back to the input V- I ...
уве вонг's user avatar
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Test to determine the CMRR in a measurement device with 4-20mA input

I would like to measure the CMRR on a measuring instrument for 4-20mA current loops. The goal is to measure the CMRR of the entire system, not just the amplifier. That is, the relationship between the ...
AlvaroQ's user avatar
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1 answer
53 views

How to drive 0-85mA proportional solenoid valve with WAGO PLC 4-20mA or 0-10V?

I am looking to use an SMC PVQ valve. I need to drive it using a WAGO PLC. Common modules for the WAGO PLC are 4-20mA and 0-10V. How can I do it using these or any other module/method? Very little ...
Anthony's user avatar
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Circuit Design Explanation

Can anyone tell me how this circuit will work? I have a AI (analog input) 0-10 V / 4-20 mA and a AO (Analog Output) 0-10 V. I only have one IO pin from ESP32 from which I will use to get AI from a ...
Zunuran Nasrullah's user avatar
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81 views

4-20 mA to voltage converter: What is the significance of the 12 V power supply to Schottky diode D2 and D3

Please check this PDF https://www.electronicsworld.co.uk/wp-content/uploads/2019/04/2019ewApr-1.pdf. I really can't understand the need for 12 V supply connected with reverse bias to D2 and D3. ...
user20033862's user avatar
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2 answers
108 views

Multiple 4-20mA Transmitters from Common Referenced Analogue Inputs

I'm trying to come up with a scheme for multiple loop powered 4-20mA transmitters controlled from seperate analogue voltages, which all have a common 0V reference. My inital thought was to use an ...
Dan Twining's user avatar
3 votes
1 answer
493 views

4-20 mA current source

TLDR: given a sensing device that produces a varying resistance, how does a "sensor" change this into a 4-20 mA current flow from a 24 V supply? Various sensors (flow, fluid depth, ...) use ...
John's user avatar
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261 views

XTR116 cannot control less than ~4.4mA

I recently purchased a MikroElektronika 4-20mA T Click MCU Add On Board MIKROE-1296, which features a MCP4921 DAC and XTR116 current loop transmitter, to control a current between 4-20mA. However, I ...
Alexander Navasca Skinstad's user avatar
1 vote
3 answers
208 views

Op-amp as constant current sink

The red circled part is acting as a constant current sink circuit but I can't understand how. If someone can share the calculations or formula or even explain what is happening?
Rachit Juthani's user avatar
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1 answer
94 views

Single channel 4-20 mA current loop transmitter

I'm designing a single channel 4-20 mA current loop transmitter using XTR111 IC. By following the reference design guide from TI. link: https://www.ti.com/lit/pdf/tidub12 Circuit schematic reference: ...
John Mist's user avatar
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1 answer
492 views

4-20 mA to 0-3.3 V Conversion

I am trying to convert 4-20 mA current loop signal to 0-3.3/0-3 V output for my 10 bit ADC IC that is connected to a Raspberry pi 3B+. Schematic: The input sensor is a 12 V loop powered 4-20 mA ...
John Mist's user avatar
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2 answers
100 views

Why is my output voltage of my 4-20[mA] to 0.8-4[V] converter saturated at 2.9V?

I built a 4-20[mA] to 0.8-4[V] converter using a HCNR201 optocoupler. The diagram I used was the shown in the datasheet: I'm testing this circuit with a 0-5[V] to 4-20[mA] converter sweeping the ...
steevglez's user avatar
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1 answer
186 views

4-20mA circuit IC troubleshooting

I have two pressure transmitters that I am converting current 4-20mA signals to analog voltage 0-5Vdc signals. Both circuits should be identical, except in footprint. The IC is RCV420JP. On one ...
Feynman137's user avatar
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4-20mA loop energy harvester

I'm designing a board which is powered from 4-20 mA Hart loop. Only two wire. Actually I had 19~20V due to the 250ohm resistor of the master side. I would like to power two electronic stages 12V@4mA ...
R_Hjr's user avatar
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1 answer
437 views

High-side 4-20 mA loop protector?

Looking at the MAX14626 4-20 mA loop protector IC, it's shown in the datasheet (Typical Operating Circuit, p. 1) being placed between the transmitter/transducer and an op-amp/ADC. Is there a reason it'...
NickT's user avatar
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2 votes
2 answers
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Using an optocoupler to separate a 4-20 mA loop

I have a PLC that is powered with 3.3 V and a sensor powered with 12 V that outputs a 4-20 mA signal. In order to allow the signal to be readable by my PLC while isolating the current in the 12 V loop ...
Jman's user avatar
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How are I3_min and I3_max currents considered in design for discrete 4-20mA current transmitter?

How to consider Iout_min and Iout_max currents before fixing up the R1, R2, R3 and R4? The document by TI for 4-20mA current loop using discrete components For linear operation, the ratio of the ...
Tellatakula Kusuma's user avatar
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3 answers
1k views

How to operate a relay (24 VDC 8 mA) from a 4-20mA signal?

I have a PLC that can output a 24 VDC, 4-20 mA signal, but it cannot be turned off - the lowest it can go is 4 mA. I found a relay (J104D2C24VDC.20S, 24VDC, 0.20W) that per the datasheet operates at ...
kevindarm's user avatar
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632 views

Is isolation always required in a 4-20mA current loop circuit? [closed]

When designing a 4-20mA output circuit, is it always advisable to isolate the output circuitry?
Philip Sheldrick's user avatar
3 votes
2 answers
220 views

How does a 4-20mA bus powered sensor work?

I need to build a circuit that has 4-20mA input and can power sensors from the loop with 2-wire connection. Could someone explain the principle of the power circuit built in such sensors? I would be ...
Kamil's user avatar
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177 views

Transmitter / receiver connection order in current loop (4-20mA)

Is the order of transmitter and receiver connection in the current loop important? I have +24VDC power supply unit, PLC with current analog input and the sensor (for test case it's just 2.35kOhm ...
Maciej's user avatar
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422 views

4-20 mA Sensor to Raspberry Pi: Inconsistent readings

I have a 4-20 mA sensor that I want to read it with a Raspberry Pi. I use a DFRobot Current to Voltage converter board connected to an ADC (ADS 1115) that is connected to a Pi. So that way I can read ...
Kumar Nikkhil Raj Agrawal's user avatar
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1 answer
4k views

4-20ma current loop and ESP32 [closed]

Following a previous question I'm thinking of using the following design for a 4-20ma 24VDC preasure sensor with an ESP32 ADC pin Will it actually work? Should I add aditional protection like two ...
Marc's user avatar
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2 answers
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4-20 mA current loop with a 3.3 V microcontroller

I have an analog pressure sensor that I am trying to read. The sensor is powered by 24 V and outputs a 4-20 mA signal. I want to connect it to an ADC pin of a 3.3 V micro. There are two designs I'm ...
Marc's user avatar
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2 votes
1 answer
2k views

Circuit for 4-20mA to I2C conversion

Hello I have a circuit that takes a 4-20mA reading from a pressure transmitter and converts it to analog 0-5V then to I2C. But it doesn't seem to be reading I just see about 0.5V on the serial ...
Feynman137's user avatar
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Multiple receivers on a 4-20mA loop with one of them with common ground

I'm trying to design a PCB to read some 4-20mA sensors in an already existing setup. The existing setup uses a NI 9207 adquisition board, which has an input impedance of 85 ohm per current channel, ...
maniel92's user avatar
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1 answer
389 views

Resistors at ADC input of 4-20mA receiver

I'm looking into building a 4-20mA receiver and found a reference schematic. In the description, they state that it uses a resistance value of 150 Ohms to produce a 3 V when the sensor's output is ...
mmvgm1's user avatar
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1 vote
1 answer
167 views

Interfacing Burkert 4-20mA flow meter to controller

I am figuring out how we can interface the flow meter to our controller before moving onto the software part. I have never worked with a 4-20mA interface hence just looking for some advice. Below ...
Vinay Divakar's user avatar
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1 answer
72 views

Power considerations in active analog outputs

I need to build 2 active 4-20mA outputs from a 24V supply voltage with unknown load conditions. One basic solution could be like the schematic below. VIn is converted to a current through R1, ...
SirNobbyNobbs's user avatar
1 vote
2 answers
670 views

Current Source - using Op-Amp and MOSFET

I would like to implement the current source circuit above to output a 4-20mA. Vin coming in from non-inverting input on IC1 is 0-5V. I am also adding 1nF capacitor and 10k resistor as shown to ...
RC-95's user avatar
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4-20 mA analogue signal conversion to flow rate

I have the following control setup: For that, I have data recorded for every I/O block, and I am asked to determine the function used by the AIN block to convert from an analogue 4-20 mA signal to a ...
HWIK's user avatar
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1 vote
2 answers
3k views

4-20 mA sensor output to STM32 ADC input

I have a industrial sensor with 4-20mA output and I want to read that output from Stm32 ADC pin but I need suggestions to do that work in a nice way. Can you guys suggest me the best way to do it? It ...
vision34's user avatar
1 vote
2 answers
3k views

How to make 4-20mA Sink Generator to Simulate with PLC or other 4-20mA Instruments? [closed]

I want to test Pressure Transmitters without actually pressure available in LAB. So I want to make 4-20ma Simulator. I changed my Title to 4-20mA Sink Generator. As I am referring to 2 Wire ...
Kalpesh's user avatar
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2 answers
873 views

4-20mA sensor to a microcontroller

I need to connect a sensor with a 4-20 mA loop to a microcontroller. The MCU operates at 3.3V and the following image is from the sensor's datasheet. I'm planning on converting the 4-20mA to a 0.6-3V ...
mmvgm1's user avatar
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0 votes
2 answers
100 views

How can I create feedback measurement with an operational amplifier? 0-20mA measurement

I want to build something like this. This circuit controls 0-20mA but the circuit have one big problem. If the circuit load e.g 100 Ohm changes to e.g 200 Ohm, then less current is going to flow. To ...
euraad's user avatar
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388 views

4-20mA to voltage breakout: part identification

I am trying to recreate the SEN0262 current to voltage circuit and embed it into my own board. As you can see, the schematics looks pretty good, but I'm unable to identify the D1, D2, and D3 diodes. ...
VirtApp's user avatar
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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 ...
Ryan Griggs's user avatar
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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 ...
Matt001's user avatar
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298 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 ...
euraad's user avatar
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1 vote
1 answer
415 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 4-20 mA current loop. I start read this article: https://instrumentationtools.com/hart-...
Vesa95's user avatar
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3 answers
5k 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/...
power machines's user avatar