Frequency synchronisation
    2.
    发明公开
    Frequency synchronisation 失效
    Frequenzsynchronisierung。

    公开(公告)号:EP0416877A2

    公开(公告)日:1991-03-13

    申请号:EP90309675.8

    申请日:1990-09-04

    IPC分类号: G06F1/12

    CPC分类号: H03L7/00

    摘要: A synchronisation circuit (16; 40) synchronises the frequency of a frequency/pulse width control circuit (14) with the frequency of a switching power supply circuit (12) for a vortex shedding flowmeter. Synchronisation can be achieved by pre-triggering the frequency of the frequency/pulse width control circuit (14) with a signal provided by the switching power supply circuit (12). Alternatively, a down-counter approach can be utilised to achieve similar frequency synchronisation.

    摘要翻译: 同步电路(16; 40)将频率/脉冲宽度控制电路(14)的频率与用于涡流脱落流量计的开关电源电路(12)的频率同步。 可以通过利用由开关电源电路(12)提供的信号预先触发频率/脉冲宽度控制电路(14)的频率来实现同步。 或者,可以利用递减计数器方法来实现类似的频率同步。

    On-line serial communication interfaces
    3.
    发明公开
    On-line serial communication interfaces 失效
    上线串行通信接口。

    公开(公告)号:EP0213768A2

    公开(公告)日:1987-03-11

    申请号:EP86305967.1

    申请日:1986-08-01

    IPC分类号: G08C19/02

    CPC分类号: G08C19/02

    摘要: An on-line serial communication interface (24) effects interfacing between a digital circuit or communication device, such as a computer or hand held terminal, and a current loop which has lines for connecting a transmitter (10) to a power supply (16). The interface includes a diode (D1) connected in series with one of the lines (14) of the current loop. The diode (D1) is connected in parallel to a source and drain (34,36) of a field effect transistor (F1). A control gate (38) of the FET is connected to an output of a differential amplifier (32) which receives, at one input thereof, a digital voltage pulse signal from the digital circuit. Another input of the amplifier (32) is held at a selected voltage so that voltage pulses are outputted from the amplifier (32) when the digital circuit generates its voltage pulses. This turns the field effect transistor (F1) on and off in synchronism with the voltage pulses, thus cutting the diode (D1) in and out of series with the line (14). With the field effect transistor (F1) in its non-conducting off condition, the diode (D1) has a small voltage drop thereacross. This does not affect the current on the current loop. With the field effect transistor (F1) conducting and in its on state, the diode (D1) is cut out and its voltage drop is applied to the transmitter (10) which is connected to the current loop. Communication can thus be established with the transmitter (10) while avoiding any interruption in the current on the current loop.

    On-line serial communication interfaces

    公开(公告)号:EP0212897A2

    公开(公告)日:1987-03-04

    申请号:EP86305965.5

    申请日:1986-08-01

    IPC分类号: G08C19/02

    CPC分类号: G08C19/02

    摘要: An on-line serial communication interface (22) effects interfacing between a transmitter (10) of a two-line current loop to a digital circuit, such as a computer or hand-held terminal which receives and processes digital voltage pulses. The interface (22) includes a comparator (32) having a non-inverting input connected by a capacitor (C 1) to one (14) of the current lines, and a inverting input connected to a source of small positive voltage. An output of the comparator (32) is connected to an input port of the digital device. The transmitter (10) modulates the current on the current loop by a small amount with respect to the analog current communicated by the transmitter (10). This generates voltage pulses in the capacitor (C 1) which are compared to the selected voltage and are amplified to form large voltage pulses used for digital communication with the digital circuit.

    Measuring energy in fuel gases
    5.
    发明公开
    Measuring energy in fuel gases 失效
    燃油中的能量测量

    公开(公告)号:EP0438859A3

    公开(公告)日:1993-11-10

    申请号:EP90312486.5

    申请日:1990-11-16

    CPC分类号: G01N33/225 G01N27/419

    摘要: A device (40) for measuring energy in fuel gas comprises a solid electrolyte oxygen pump (10) for generating an amount of oxygen in response to current being supplied to the pump (10). A sample of the gas is mixed with the oxygen from the pump (10) to produce a mixture which is subjected to complete combustion in a catalytic combuster (12). An oxygen sensor (14) is connected to the catalytic combuster (12) for measuring excess oxygen in the exhaust gas from the combuster (12). A signal from the oxygen sensor (14) is compared in a feedback control unit (22) to a known and desired amount of excess oxygen in the exhaust gas. If there is too much or too little oxygen in the exhaust gas, a feedback signals used to adjust the value of current being supplied to the oxygen pump (10) until the actual amount of excess oxygen is equal to the selected amount of excess oxygen. The selected amount of excess oxygen is indicative of complete combustion of the sample mixture. With the excess oxygen equalling the desired oxygen in the exhaust gas, the value of current being supplied to the pump (10) is used to calculate the energy in the fuel sample.

    Current loop arrangements
    9.
    发明公开
    Current loop arrangements 失效
    设施电流回路。

    公开(公告)号:EP0213767A2

    公开(公告)日:1987-03-11

    申请号:EP86305961.4

    申请日:1986-08-01

    IPC分类号: G08C19/02

    CPC分类号: G08C19/02

    摘要: A serial communication interface establishes communication with a microprocessor (18) of a transmitter (10) from a current loop which is powered by a power supply. The microprocessor (18) outputs an analog signal corresponding to a process variable (PV) and also can receive a serial communication voltage pulse signal. The analog signal is applied to a current regulating circuit (40) which draws current from the power supply into the current loop in an amount which is proportional to the process variable (PV). A comparator (44) i the form of an operational amplifier has an output connected to the microprocessor (18) for applying the serial communication voltage pulse signal to the microprocessor. The comparator (44) has one input (48) which is held at a slight negative voltage and another input (46) which is connected to a line of the current loop connected to the negative terminal of the power supply. To establish communication from the current loop to the microprocessor (181, voltage on the current loop is modulated by a small amount to generate small voltage pulses which are applied to another (non-inverting) input (46) of the comparator (44). The comparator (44) amplifies the small voltage pulses into larger voltage pulses which are then applied to an input (32) of the microprocessor (18) to establish digital communication with the microprocessor. In this way, the analog signal on the current loop can be maintained simultaneously with digital communication between the loop and the microprocessor (18).