| 摘要 |
A meter device, e.g. a flow meter, including a signal generator (Fo) for sending a quantity signal (QS), e.g. a pulse signal, according to the measured physical quantity on a communication line (CL), e.g. a one-wire connection. The meter device further has a request detector (Fi) for detecting a request signal (SIR) on the communication line (CL), such as a request signals (SIR) from an associated external unit. The signal generator (Fo) and the detector (Fi) are interconnected so that the signal generator (Fo) stops sending the quantity signal (QS) when the request signal (SIR) has been detected. Preferably, the meter device is arranged for additional communication, e.g. 2-way communication between the meter device and a calculator unit, after having stopped sending the quantity signal (QS). Such additional data may be e.g. temperature data from a flow meter to a heat calculator, or configuration data sent from the heat calculator to the flow meter. Restart of sending the quantity signal (QS) can be initiated by request via the communication line (CL), or initiated by the meter device itself after expiration of a predetermined time. In some embodiments, the signal generator (Fo) generates the quantity signal (QS) by operating an electronic two-state switch connected between electric ground and the communication line (CL), e.g. with the communication line (CL) connected to a voltage potential via an impedance. In other embodiments, the signal generator (Fo) includes a three-state switch for connecting the communication line (CL) to one of: 1) electrical ground, 2) a voltage potential, and 3) high impedance, such as open circuit. The three-state switch may be connected to the communication line (CL) via an impedance. |
