Rotronic presents transmitters for measuring relative humidity and temperature in explosive environments: The HF520-EX series and the interchangeable HC2-EX probes are ATEX and IECEx approved. They comply with the international standards IEC 60079-0/11/18/26/31/7. The series consists of a robust aluminum transmitter with or without display. The connected sensors are encapsulated in a stainless steel tube and approved for operation in Zone 0/20. The transmitter itself is approved for zone 1/21. Thanks to a special circuit design with galvanic isolation, no intrinsically safe power supply is required.