Abstract: A blower supplies compressed air to a predetermined place. The blower is provided with a plurality of compressors, a common air tank for storing compressed air supplied from the compressors, a changeover valve for switching the compressed air taken in from the air tank between a first supply state and a second supply state, and a controller for controlling operations of the compressors and the switching operation of the changeover valve. The controller can select one operation pattern from among a plurality of operation patterns determined by combinations between the compressors and the changeover valve.

Abstract: A data transfer system for transferring a transfer frame including a plurality of character codes representing a numeral of numerical data to be transferred, error detection data including a parity code for the character codes and a predetermined transfer control code to a controller on a receiver side from a controller on a sender side. In the controller on the sender side, a parity code obtained for the character codes is divided into a plurality of bit groups, a predetermined code which does not coincide with the predetermined transfer control code is affixed to each divided bit group to form divided parity data having a specific number of bits, and the transfer frame is constituted with these plural divided parity data as the error detection data. In the controller on the receiver side, the original parity code is restored from a plurality of divided parity data in the received transfer frame and is used.

Abstract: A meter at each user's house has a bar-coded user number shown thereon, and has a display section for displaying a reading. A data input terminal unit has a bar code reader for reading the user number and a keyboard for manually inputting a present reading. A data recording controller has a meter reading data file having a present reading for each user number. The data input terminal unit radio-transmits a read user number to the data recording controller and radio-receives a previous reading, corresponding to the user number, from said data recording controller. The data input terminal unit computes the amount used from this previous reading and the present reading manually input, and causes a printer to print meter reading data including this used amount on a reading slip while radio-transmitting it to the data recording controller.

Abstract: A casing of a portable data input/transmission apparatus has an end portion, the size of which is determined such that the end portion can be held by one hand. A pen-scanner type bar code reader for reading a bar code is attached to one end of the casing in the longitudinal direction. A keyboard for enabling at least numerical data to be input is attached near the other end of the casing in the longitudinal direction. A transmitter/receiver is stored within the casing, the transmitter/receiver being designed to output wirelessly to an external data processing apparatus code data read by the bar code reader and at least numerical data input from the keyboard. A pair of antenna-containing grooves are formed in a pair of facing side surfaces extending in the longitudinal direction of the casing, such that the grooves extend in the longitudinal direction of the casing to said other end of the casing.

Abstract: A portable data input apparatus comprises an elongated casing. A pen-scanner type bar code reader reads a bar code provided according to the kind of a commodity, and outputs a corresponding code data unit. A keyboard is designed to input at least a numerical data unit representative of the amount of the commodity. A display device displays the code data unit and the numerical data unit. A display mode changing circuit is designed to invert the image of the data units displayed on the display device in the vertical direction and the horizontal direction, in response to a detection signal, which is output when the code data and numerical data are inversely displayed.

Abstract: A measuring device having a transmitter includes a measuring device section, a data processing unit, a transmitter, and a casing. The measuring device section converts measuring data into a digital value and outputs it. The data processing unit arranges the measurement data obtained in the measuring device section in a transmission data string having a predetermined format and outputs it. The transmitter transmits the transmission data, which is output from the data processing unit, by radio transmission. The transmitter is housed in the casing, which is attached to a portion near an operation section of the measuring device section, together with the data processing unit. An antenna output terminal of the transmitter is connected to the casing or a conductor portion near the casing.

Abstract: A host apparatus collects the physical or chemical quantities of articles, which have been measured by a plurality of measuring devices, for example, vernier calipers. Each calipers has a caliper unit as a measuring means, a dip-switch, a CPU, a RAM, and a transmitter. The caliper unit has an analog-to-digital (A/D) converter. The dip-switch is operated, thus setting an ID number of the device, before the device is used. The ID number is stored into the RAM. When the transmission button of the device is pushed, the CPU edits the digital value supplied from A/D converter and the ID number stored in the RAM, thereby forming a serial-data message. This message is transmitted by a transmitter, in the form of a radio message. The host apparatus has a receiver and a host computer. The receiver received the serial-data messages transmitted from the measuring devices.

Abstract: A caliper unit has a connector having connecting terminals. The caliper unit measures a value of a product, and generates digital data representing this value. A data-transmitting apparatus has a housing. The housing can be attached to caliper unit. The housing has a fastening ring and a connecting plug. The plug can be connected to the connector of the caliper unit by the fastening ring. A microcomputer including a CPU is provided within the housing. A RAM is also provided within the housing, for storing the digital data input from the caliper unit and also an identification (ID) number assigned to the data-transmitting apparatus. The microcomputer forms a serial-data message from the digital data and the ID number, both stored in the RAM. A transmitter is provided within the housing, for transmitting the serial-data message in the form of a radio message.

Abstract: The analog data representing a value measured of a product by means of a measuring device such as a vernier calipers is converted into digital data by an analog-to-digital converter. A CPU incorporates the digital data into a data message. The CPU is driven by a clock signal output from a quartz crystal oscillator. A first frequency divider divides the clock signal, thus generating a signal of a first frequency, and a second frequency divider divides the clock signal, thereby generating a signal of a second frequency. During the duration of each digital data signal at the "0" (low) level, the CPU generates a signal at the "low" or "high" level, in accordance with the signal generated by the first frequency divider. Similarly, during the duration of each digital data signal at the "1" (high) level, the CPU generates a signal at the "low" or "high" level, in accordance with the signal generated by the second frequency divider. The signals generated by the CPU are supplied to a transmitter.

Abstract: An oscillator outputs an oscillator frequency corresponding to a moving distance of a probe. A counter counts the oscillator frequency of the oscillator. A computer calculates the moving distance. A display unit displays the moving distance computed by the computer. A voltage booster and a voltage stabilizing circuit are connected between the oscillator and a battery. The driving voltage from the battery is supplied to the oscillator through the voltage booster and the voltage stabilizing circuit, and is supplied to the counter, computer and the display unit without passing through the voltage booster and the voltage stabilizing circuit in order to reduce the power dissipation.

Abstract: When a probe of a displacement measuring apparatus is moved, a core member connected to the probe is also moved through coils of an oscillator. A movement distance of the probe is calculated in accordance with a change in an oscillation frequency generated in correpondence with the movement of the core member. If strict displacement measuring is to be performed, the non-linear relationship between the moving distance of the core member and the change in the oscillation frequency must be taken into account, i.e., the relationship therebetween is measured in linear manner, the movement distance is calculated and then secondary curvature correction is performed to correct for the linear measurement. Therefore, measurement precision of the displacement measuring apparatus can be greatly improved as compared to that of a conventional displacement measuring apparatus.

Abstract: An FSK shift keying device includes a detector for detecting a transmission frame consisting of a preamble, data, and a postamble, a time constant circuit charged in response to a voltage signal detected by the detector for generating a time constant, a charging voltage being determined in accordance with the time constant set in correspondence with a duration of high level in the preamble of the transmission frame, a reference voltage generator for generating a reference voltage signal having an amplitude value which is 1/2 an amplitude value of the voltage signal from the detector, and further generating a comparison reference voltage signal obtained by subtracting the reference voltage from the charging voltage, and a comparator for comparing the comparison reference voltage signal with the voltage signal input from the detector.

Abstract: A receiver includes a signal-receiving section for receiving input signals and outputting detection signal, and a power source for supplying power thereto. A first detector detects a preamble of each input signal while a second detector detects the end of a postamble of each input signal. A power supply section supplies the power to the signal-receiving section by turning on a switch connected between the signal-receiving section and the power source when the first detector detects the preamble of the input signal. A periodic power-supply section turns on the switch periodically to supply the power periodically to the signal-receiving section when the second detector detects the end of the postamble of each input signal.

Abstract: An FSK shift keying device includes a detector for detecting a transmission frame consisting of a preamble, data, and a postamble, a leading edge detector for detecting a leading edge of a voltage signal detected by the detector, a microprocessor for receiving a detection signal output from the leading edge detector as an interrupt signal, and resetting and restarting a timer, the timer for counting a time lapse in accordance with a clock signal from a clock generator, a sample and hold circuit for holding the voltage signal output from the detector when the time lapse counted by the timer reaches a duration of the preamble, a reference voltage generator for generating a reference voltage signal having an amplitude value which is 1/2 an amplitude value of the voltage signal from the detector, and a comparator for comparing the reference voltage signal with the voltage signal from the sample and hold circuit.

Abstract: In a length measuring apparatus, a measurement probe includes a core and is movable in an axial direction of the probe. First to third coils are arranged in an order in a moving area of the core in accordance with the movement of the probe. In the B-phase, the first and second coils are primary and the second and third coils are secondary. In the A-phase, the second and third coils are primary and the first and second coils are secondary. CPU first sets a switch in the B-phase and then in the A-phase. A moving amount of the core is calculated from secondary voltage data in both the B-phase and the A-phase.

Abstract: At the start of measurement by a length measuring device, a calibration coil in which the temperature characteristics are known, is connected to an oscillator. The oscillation frequency of the oscillator at this time is counted by a counter and is given to microcomputer. Microcomputer obtains temperature information corresponding to counted numbers with reference to a table of counted numbers versus temperature information which has already stored temperature information corresponding to a plurality of counted numbers and stores the obtained temperature information in a data storage area. In measurement mode, measured values subjected to temperature compensation are obtained according to the temperature information stored in the data storage area.

Abstract: An oscillator oscillates at a frequency determined by the distance moved by a probe. The probe in contact with an object under measurement, moves according to the displacement of the object. A controller computes the distance moved by the probe from a reference position at predetermined time intervals by using the shift of the oscillating frequency of the oscillator. The controller further decides if the computed distances are within a predetermined range. If the computed distances moved are within that range, the controller supplies the computed distance moved to a transmitter, which in turn wirelessly transmits the distance. When the computed distance moved is outside the predetermined range, the controller does not output the distance moved to the transmitter, nor does it supply the distance moved every four computations of the distance moved.