4 mA to 20 mA Process Control Loop Using the AD5662 DAC
4 mA to 20 mA Process Control Loop Using the AD5662 DAC (cn0009)
In many process control applications, 2-wire current transmitters are often used to transmit analog signals through noisy environments. These current transmitters use a zero-scale signal current of 4 mA and a full-scale signal current of 20 mA–hence the designation "4 mA to 20 mA converter." The circuit described in this document provides a low power current transmitter with 16-bit resolution and monotonicity, which is powered directly from the 4 mA to 20 mA control loop power supply and consumes less than 4 mA. Transmitters requiring more than 4 mA cannot be powered directly from the loop power supply and, therefore, require an additional supply.
Figure 1: Programmable 4 mA to 20 mA Process Controller (Simplified Schematic)
4mA to 20mA loop current generator
Схемы и диаграммы
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