Abstract
In Fukushima Daiichi Nuclear Power Plant, it is necessary to use a radiation-hardened remote communication system to control remotely working robots. Currently, we are developing a radiation-hardened remote communication system using a DE1-SoC field programmable gate array (FPGA) board. When a communication must be done under a radiation-environment, soft error and total-ionizing-dose tolerances must be considered. To block the phenomena, a triple modular redundant design was introduced. We have developed a triple modular redundant serial communication circuit for a 200 m metal-wired communication between a computer and the remotely located system. The serial communication circuit mainly consists of triple modular redundant delay type flip flops, majority voting circuits, and state transition logic circuits. For long-distance communication, the hardware macros of differential input ports and differential output ports were used on a Cyclone FPGA. Here, we are using a serial communication data format constructed by 8 bits data, a start bit, a stop bit, and a parity bit.
Using the serial communication circuit, we conducted a bidirectional communication test using 200-meter wires. In this test, no errors were observed when the communication frequency is lower than 8.0 MHz.
