Abstract: In a method for transmitting data from a central station to a plurality of data stations via a multipoint connection according to a prescribed transmission protocol, every data station has an address allocated to it under which it receives data and outputs messages to the central station. When at least two data stations request data from the central station, the central station (Z) selects one of the data stations that request data and communicates the address of the selected data station (K1) to the further data station (K2, K3, Kn). In response thereto, the latter modifies its address to the address of the selected data station (K1). The central station (Z) transmits data to the selected data station (K1) that is also received by the further data station (K2, K3, Kn), whereby the transmission protocol is only processed between the central station (Z) and the selected data station (K1) during the data transmission.

Abstract: In liquid measuring apparatus, a cable supporting a sensing plate is attached to a drum that is connected via a magnetic clutch with the drive shaft of a servomotor. The servomotor is supported in a pivot mount which is flexibly rotatively connected to the apparatus housing. In response to liquid level changes, a contactless sensor generates a signal which is compared with a balance of moments reference signal in a comparator to develop a deflection signal which, after conversion into frequency pulses in fast servocontrol circuitry, activate the servomotor in one direction or the other as determined by a polarity switch activated by a directional decoder. Inaccuracies due to parts vibrations are compensated for. Also, measurement disturbances caused by waves at the surface of the liquid are avoided with the aid of slow servocontrol circuitry which, after a delay, activates the servomotor with an adjustable frequency supplied by an oscillator.