0-10V 4-20mA Signal Generator Circuit
Introduction
In industrial automation, signal generators play a crucial role in generating signals for testing, calibration, and simulation of various industrial equipment. One of the most common signal standards used in industrial automation is the 4-20mA current loop signal, which is used to transmit analog signals over long distances. In this article, we will discuss a simple 0-10V 4-20mA signal generator circuit that can be used to generate both voltage and current signals.
Circuit Description
The circuit consists of two main components: a voltage-controlled current source (VCCS) and a voltage amplifier. The VCCS is used to generate the 4-20mA current signal, while the voltage amplifier is used to generate the 0-10V voltage signal.
Voltage-Controlled Current Source (VCCS)
The VCCS circuit is based on the popular LM324 op-amp. The circuit is shown below:
+-----------+
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| R1 R2 |
| 1k 1k |
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+-----------+
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v
+-----------+
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| R3 R4 |
| 2k 2k |
| |
+-----------+
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|
v
+-----------+
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| LM324 |
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+-----------+
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|
v
+-----------+
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| R5 R6 |
| 1k 1k |
| |
+-----------+
The VCCS circuit works by converting the input voltage (Vin) to a current signal (Iout) through the following equation:
Iout = Vin / R3
The op-amp is used to amplify the input voltage and provide a high impedance output.
Voltage Amplifier
The voltage amplifier circuit is based on a non-inverting amplifier configuration using another LM324 op-amp. The circuit is shown below:
+-----------+
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| R7 R8 |
| 1k 2k |
| |
+-----------+
|
|
v
+-----------+
| |
| LM324 |
| |
+-----------+
|
|
v
+-----------+
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| R9 R10 |
| 2k 2k |
| |
+-----------+
The voltage amplifier circuit amplifies the input voltage (Vin) to a gain of 2, which means that the output voltage (Vout) is twice the input voltage.
Circuit Operation
The circuit operation is as follows:
- The input voltage (Vin) is applied to the VCCS circuit, which converts the voltage to a current signal (Iout).
- The current signal (Iout) is then applied to the voltage amplifier circuit, which amplifies the signal to a gain of 2.
- The output voltage (Vout) from the voltage amplifier circuit is then connected to a load resistor (Rload) to convert the voltage signal back to a current signal.
Applications
The 0-10V 4-20mA signal generator circuit has several applications in industrial automation, including:
- Testing and calibration: The circuit can be used to test and calibrate industrial equipment that uses 4-20mA current loop signals.
- Simulation: The circuit can be used to simulate industrial equipment that uses 4-20mA current loop signals.
- Industrial automation: The circuit can be used in industrial automation applications where 4-20mA current loop signals are used to transmit analog signals over long distances.
Conclusion
In this article, we have discussed a simple 0-10V 4-20mA signal generator circuit that can be used to generate both voltage and current signals. The circuit is based on two main components: a voltage-controlled current source (VCCS) and a voltage amplifier. The circuit has several applications in industrial automation, including testing, calibration, simulation, and industrial automation.
