Method, communication module and system for transmitting diagnosis data of a field device in an installation for process automation

A method for transmitting diagnosis data of a field device in an installation for process automation, wherein the field device has a communications link to a superordinate unit via a wired communications loop;

• comprising:
• providing a communications module, the communications module including:
• a transducer unit embodied to convert alternating current (AC) communication signals and pulses that are modulated onto a direct current (DC) signal on the communications loop into electrical energy;
• an energy storage unit connected with the transducer unit and embodied to store the converted electrical energy;
• a polling unit configured to communicate with the field device and to poll diagnosis data of the field device via the communications loop;
• and
• a transmission unit embodied to wirelessly transmit the polled diagnosis data to a reception unit via radio waves;
• connecting the communications module to the communications loop in parallel with the field device;
• capturing with the transducer unit in the communications module the AC communication signals and pulses on the communications loop emitted by the superordinate unit or by the field device and converting the AC communication signals and pulses into electrical energy;
• storing the converted electrical energy in the energy storage unit of the communications module up to a predetermined limit value;
• polling the diagnosis data of the field device using a communication command of the polling unit of the communications module;
• receiving the diagnosis data of the field device by the communications module via a communication command sent by the field device;
• and
• wirelessly transmitting the polled diagnosis data from the communications module to a reception unit as soon as the electrical energy stored in the energy storage unit reaches or exceeds the predetermined limit value and/or if the communications module receives a command for polling or transmitting.