"The WG 21 repeater power sup- ply is used to supply intrinsically safe 2-wire transmitters. It sup- plies the transmitter with power and transmits the measurement signal to the output galvanically isolated and with high accuracy. In addition to the analog signal, the WG 21 also optionally trans- mits data protocols for SMART transmitters (HART ® ). It allows bidirectional communication with the field device from every point of the cabling.","The WG 21 provides Safe Isolation and high insulation between the input, output, and power supply.","The high supply voltage, the good hazardous area ratings and the broad-range power supply allow universal use. Cables 1400 m in length can therefore be used without any problems. Thanks to a new transformer transmission technique, the WG 21 achieves an extraordinari- ly high transmission accuracy for hazardous-area applications. The encapsulation provides maximum operating safety, long-term stability, and disruptive strength even under extreme ambient conditions."