A peripheral module for connecting Highway Addressable Remote Transducer (HART) field devices provides different HART variables to the input area of its address space for cyclic reading by a CPU unit and continuously updates these HART variables, wherein a communication area for transmitting an individual HART variable is provided in the input and output area of the address space, where the CPU unit writes a command, which specifies the current HART variable to be read, into the output area of the communication area and the peripheral module provides and updates the specified HART variable in the input area of the communication area until a time at which the CPU unit writes a new command, which specifies another HART variable to be read, into the output area in order to make the transmission of all potentially available HART variables possible in a simple manner.