Design and Implementation of A Current Signal Isolator Based on FPGA

In the field of industrial measurement and control, analog signals, such as pressure, temperature, valve opening, and flow, are widely transmitted in the form of current signals. Analog signals often need to participate in a variety of control or display process loops after being converted into current signals. To ensure the stable and reliable operation of the industrial process control system, the input current signal needs to be converted and output by an isolator. However, the isolator has conversion error and the conversion errors of different channels of the isolator are generally different, so the current values of different output channels of the isolator are generally inconsistent. With the long-term operation of the industrial process control system, this numerical difference may increase gradually be unbearable. To solve this problem, this paper proposes a design scheme of the current isolator based on FPGA. In this design scheme, FPGA collects the current value of each output channel, runs the automation correction algorithm, adjusts the value of the output current dynamically, and finally makes the current value of each output channel remain consistent. The hardware implement and test of the current isolator are carried out and the test results show that this isolator implementation scheme is feasible.