摘要:
A voltage/current verifier computes, for each phase, a phase difference between phase voltage and phase current from the phase of phase voltage and the phase of phase current computed for each phase by a phase acquirer, and determines conformity if all of the computed phase differences are within a preset range. A current/current verifier computes phase differences between phase currents from the phase of phase current computed for each phase by the phase acquirer, and determines conformity if all of the computed phase differences are less than 180°. A reporting device reports that a current transformer is incorrectly placed on a power line unless both the voltage/current verifier and the current/current verifier do not determine conformity.
摘要:
A presence detection system is equipped with a transmitter that transmits a multipath wireless signal and a receiver that detects the presence of a person by receiving the transmitted wireless signal, within a prescribed space. On the basis of the reception level for a wireless signal received intermittently at the beginning of a first interval, the receiver determines whether there has been a change in the present/absent state of a person. When it is determined that there has been a change in the present/absent state of a person, the receiver determines whether a person is present/absent on the basis of variation in the reception level for a wireless signal received at the beginning of a second interval, which is shorter than the first interval.
摘要:
A power measuring device stores in a set phase relation storage whether the load connected to a three-phase, four-wire power source is inductive, capacitive, or neither of them, in other words whether the phase currents are ahead, delayed, or matching phases with respect to the phase voltages, and determines whether the stored phase relation coincides with the determined phase relation. Then, the incorrect connection that cannot be verified in the prior art, more specifically the primary conductors of the current transformers of the current xfrms that are all arranged reversely while the voltage terminals are connected correctly, can be detected as an incorrect arrangement.
摘要:
A signal conversion system comprises measuring units, a switcher, a converter, and a host. The converter mutually converts signals transmitted in compliance with a first protocol for communicating with a pre-specified party and signals transmitted in compliance with a second protocol different from the first protocol. The host specifies a given measuring unit among the measuring units communicating in compliance with the first protocol. Then, the switcher switches the transmission channel of signals transmitted in compliance with the first protocol to the transmission channel connecting the measuring unit specified by the host and the converter.
摘要:
A power measuring apparatus includes a line connector connected to a power source line, which supplies power to equipment; and a measuring circuit, which measures a voltage and a current supplied to the equipment by means of the connected power source line. The power measuring apparatus also includes a calculator which calculates, on the basis of the measured voltage and current, power consumed by the equipment; and a transmission line connector connected to a transmission line that transmits data used for the purpose of monitoring the equipment. Furthermore, the power measuring apparatus also includes a transmitter that transmits data indicating the calculated power to the transmission line. Consequently, the power measuring apparatus can be installed in equipment at lower cost than before.
摘要:
A presence detection system is equipped with a transmitter that transmits a multipath wireless signal and a receiver that detects the presence of a person by receiving the transmitted wireless signal, within a prescribed space. On the basis of the reception level for a wireless signal received intermittently at the beginning of a first interval, the receiver determines whether there has been a change in the present/absent state of a person. When it is determined that there has been a change in the present/absent state of a person, the receiver determines whether a person is present/absent on the basis of variation in the reception level for a wireless signal received at the beginning of a second interval, which is shorter than the first interval.
摘要:
An electric field intensity measuring circuit measures the electric field intensity of each of multiple communication channels available for data communication. A channel determiner compares electric field intensities measured by an electric field intensity measuring circuit with multiple different thresholds including a first threshold as the carrier sense threshold and a second threshold that is the detrimental interference level the interference of which causes the reception sensitivity to deteriorate, counts the numbers of times that the electric field intensity exceeds the thresholds on each communication channel, and selects a communication channel for use based on the counted numbers of times that the thresholds have been exceeded on the communication channels.
摘要:
An electric field intensity measuring circuit measures the electric field intensity of each of multiple communication channels available for data communication. A channel determiner compares electric field intensities measured by an electric field intensity measuring circuit with multiple different thresholds including a first threshold as the carrier sense threshold and a second threshold that is the detrimental interference level the interference of which causes the reception sensitivity to deteriorate, counts the numbers of times that the electric field intensity exceeds the thresholds on each communication channel, and selects a communication channel for use based on the counted numbers of times that the thresholds have been exceeded on the communication channels.
摘要:
High-accuracy overcurrent detection is performed, while a loss resulting from the current detection is significantly reduced. A switch section outputs the voltage between the both terminals of a current detection resistor using an AND signal between an output signal from a hysteresis comparator and an output signal from a pre-driver. The voltage is filtered by an electrostatic capacitor element and a resistor, and inputted to a comparator. The comparator makes a comparison between the signals inputted to the two input terminals thereof, and outputs the result of the comparison to a digital filter. When an overcurrent begins to flow in a power supply unit, the levels of the voltages inputted to the two input terminals of the comparator are inverted so that the comparator outputs an inversion signal to the digital filter. The digital filter outputs a detection signal to an overcurrent detection circuit when an arbitrary time has elapsed.
摘要:
Many frozen foods are now sold on the market and also produced by household refrigerators, and most of these frozen foods are eaten after thawing or after cooking under heat subsequent to thawing. The importance of thawing is thus increasing more and more. This invention provides a heating apparatus of simple construction capable of effectively thawing a frozen food to meet the above demand. The heating apparatus of the present invention is based on the fact that the dielectric loss of a frozen food itself varies as the frozen food is progressively heated. In the heating apparatus, a signal wave is directed toward a frozen food, and the variation of the rate of absorption of the signal wave due to the dielectric loss of the food is measured, so as to automatically control the process of heating for thawing on the basis of the result of measurement.