4 20ma Receiver Circuit Schematic

In two wire 20ma control loops we use 2 wire transmitters to convert various process signals representing.

4 20ma receiver circuit schematic.

Figure 2 4 20ma test sender. This 4 20ma current loop transmitter can be used in any industrial smart sensor and other devices that use 4 to 20ma current transmission. That is exactly what it was designed for and it works very well indeed. Before i started setting up my small contract manufacturing business i was a pure electronics designer.

Simplified schematic for 4 ma to 20 ma receiver configuration resistor r6 is used to sense the 4 ma to 20 ma signal and convert it into a 0 2 v to 1 v input voltage to the amplifier. R7 1 k roff 1 m pot. A supply connection and a ground or return connection. The circuit consists of a pre mium grade operational amplifier an on chip precision resistor network and a precision 10v reference.

Consider the simple dc circuit above consisting of a power supply and three loads. 4 20ma circuit schematic as major as the ma loop standard has become in the process control. The whole circuit can operate in 3 3v or 5v supply. This is the circuit of the tester and it is not intended as any kind of real 4 20ma interface.

Back then if i needed to convert current to voltage i d use any solution based integrated circuit ic to get the job done quickly. The rcv420 features 0 1 overall conversion accuracy 86db cmr and 40v. The transmitter has only two external input terminals. However it can be used to test receiver units and their associated analogue to digital converters software etc.

As a monolithic circuit it offers high reliability at low cost. Rl 150 to 400 ohms rg 47 k pot. A simplified schematic for the voltage to current converter is shown in figure 2. Here is the schematic diagram of the basic 4 20ma current loop receiver circuit using rcv420 ic chip m at full scale the circuit cause only a 1 5v drop by its internal sense resistance which is useful in loops containing extra instrument burdens or in intrinsically safe applications where transmitter compliance voltage is at a premium.

R10 110 k r1 r2 330 k r11 1 m r3 r4 27 k r12 330 k r5 r6 27 k c1 c2 0 1 µf r8 r9 150 a1 a2 a3 1. There is a dearth of any. The rcv420 is a precision current loop receiver de signed to convert a 4 20ma input signal into a 0 5v output signal. The input voltage is then reflected across the fb and ref pins of the amplifier.

The supply voltage can be selected through header j1. Simple and effective 4 20ma current loop receiver with minimal components.