Tag Archives: Current Loop

4-20mA Current Loop Tester

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This design will interest technicians who work on pneumatically operated valves and other 4-20mA current loop controlled devices. Although 4-20mA signal injector/calibrators are available, this one is both cheap to build and easy to operate. When first powered up, the circuit sinks 4mA of current. If switch S1 is pressed,… Read more »

4mA–20mA Loop Powered Temperature Sensor

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This circuit is used to allow  a 4mA–20mA to power an analog temperature sensor. To provide a 4mA–20mA output over a 3.75V–28V compliance range this circuit uses an op-amp, low-dropout linear regulator, transistor and an analog temperature sensor. It  is powered by the loop with the only consequence being a… Read more »

RCV420: Single Chip Precision 4-20mA Current Loop Receiver

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RCV420 is a special function integrated circuit chip for 4-20mA current loop receiver. RCV420 provide complete 4-20mA to 0-5V conversion, with 0.1% overall accuracy, 86dB CMR, and ±40V common-mode input range. This IC chip is suitable for many applications: PROCESS CONTROL INDUSTRIAL CONTROL FACTORY AUTOMATION DATA ACQUISITION SCADA RTUs ESD… Read more »

Pt100 RTD Current Loop Transmitter Using XTR105

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XTR105 is a 4-20mA current loop transmitter integrated circuit, with two precision current sources. The Instrumentation amplifier gain inside this chip can be configured for a wide range of temperature or pressure measurements. This integrated circuit chip provides current excitation for platinum RTD temperature sensors and bridges, instrumentation amplifiers, and… Read more »

Single Chip Thermocouple 4-20mA Current Loop Transmiter Circuit

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Thermocouples give many benefits compared to thermistor/RTD (Resistance Temperature Devices).  Some advantages of thermocouple are their wider temperature range, their reliability, and their consistency over long period of time. In some cases,  thermocouple calibration  is even unnecessary. Thermocouple temperature sensors are widely used in temperature controllers for boilers, oven,  pressurized… Read more »

Programmable Current Source/Regulator

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This is a simple circuit of programmable current source/regulator. This circuit is used to generate current. Here is the schematic diagram of programmable current source/regulator : This circuit uses L 200 as main component. The error amplifier of this circuit is disabled by shorting pin 4 to ground. The value… Read more »

5V Powered 4-20mA Current Loop Generator

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Voltage step-up also employed in figure below, but for a different purpose. The common requirements are transmission of industry standard 4-20mA current loop signals to valves and other actuators.   Current transmitters is required by resistive line losses and actuator impedance to be able to force a compliance voltage of… Read more »

Chromel Alumel Thermocouple Current Loop Transmitter

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The schematic diagram below show signal conditioning circuit for remote current loop temperature transmitter. This thermocouple temperature transmitter is loop powered, means it doesn’t need its own power supply since the supply is provided by the current loop receiver. Thermocouple is basically a junction of two different metallic material that… Read more »