The pressure transmitter is particularly suitable for measuring volume flow of town gas supplies or other gaseous hydrocarbons such as butane, methane etc. in industrial furnaces or combustion plants. The instrument does not generate any ATEX zone as its design and technical safeguards mean it poses no ignition hazard. The measuring range is scalable in the range from 10 .. 100 %. This can be performed using a keyboard and display (optional). The measured values can be displayed in all standard units. A selectable time constant allows the transducer to be adjusted perfectly to the pressure conditions and thus ensures a stable output signal. The P 29 can be mounted either on a wall or on top-hat rails.