摘要:
A switch is provided in a supply line for an operating power supply from an operating power supply generating circuit to a main circuit, An electric current detecting circuit and a comparison evaluating circuit are provided as a controlling circuit portion for controlling the ON/OFF state of the switch. The electric current detecting circuit inputs a voltage in accordance with the value of an electric current supplied from an higher-level system, and inverts and amplifies the voltage to produce an output voltage. The comparison evaluating circuit inputs the output voltage from the electric current detecting circuit, compares the output voltage to a reference voltage, and turns the switch ON if the output voltage is higher than the reference voltage. The reference voltage is set in advance in accordance with a lower limit electric current value for the electric current that must be supplied for the main circuit to operate properly.
摘要:
In a method or device for powering a field device for a processing plant, the field device is driven by a process signal of an electrical power supply so that an electronic unit connected to the power supply outputs a process control signal. A required power level of the electronic unit is determined for outputting the control signal. A portion of an electrical power of the power supply exceeding the required power level is stored.
摘要:
In a method or device for powering a field device for a processing plant, the field device is driven by an electrical power supply so that the field device outputs a process signal. A required power level of the electronic circuit is determined for outputting the process signal. A portion of an electrical power of the power supply exceeding the required power level is stored.
摘要:
A process control instrument includes a sensor/actuator portion and a transmitter portion connected to the sensor/actuator portion. The transmitter portion is operable to communicate with other process variable transmitters through a communication network. The transmitter includes a processing module and a power module operable to generate a power output supplied to at least the transmitter portion, wherein the power module is operable to adjust the power output based on a power control signal. Moreover, the power control signal may be generated by a controller device remote from the process control instrument and communicated to the process control instrument over the communication network. Additionally, the power module includes a power control module for adjusting the power output. This power control module includes an amplitude limiter operable to limit a power input to the process control instrument according to a controllable amplitude limit, and a power rate of change unit operable to limit a rate of change of the power input to the process control instrument according to a controllable adjustment rate limit.
摘要:
A process control instrument includes a sensor/actuator portion and a transmitter portion connected to the sensor/actuator portion. The transmitter portion is operable to communicate with other process variable transmitters through a communication network. The transmitter includes a processing module and a power module operable to generate a power output supplied to at least the transmitter portion, wherein the power module is operable to adjust the power output based on a power control signal. Moreover, the power control signal may be generated by a controller device remote from the process control instrument and communicated to the process control instrument over the communication network. Additionally, the power module includes a power control module for adjusting the power output. This power control module includes an amplitude limiter operable to limit a power input to the process control instrument according to a controllable amplitude limit, and a power rate of change unit operable to limit a rate of change of the power input to the process control instrument according to a controllable adjustment rate limit.