Smc Kabushiki Kaisha

Takashi Takebayashi

Shigekazu Nagai

Yoshiharu Ito

Shigeru Sugano

Mitsuhiro Saito

Shogo Kurisaki

Hiroshi Matsushima

Tomonobu Endou

Akio Saitoh

Tomoyuki Okuyama

Ge Pinghou

Pinghou Ge

A threshold value is stored in a CPU using setting switches. When a fluid is introduced into a flow passage, a rod disposed in the flow passage sheds Karman vortexes downstream thereof in the fluid as it flows through the flow passage. A piezoelectric device generates an electric signal depending on pressure fluctuations of the Karman vortexes, and the electric signal is applied through a comparator to the CPU. The CPU refers to a data table stored in a memory to determine a flow rate of the fluid based on the period of the electric signal. When the determined flow rate is greater than the threshold value, the CPU turns on transistors to energize loads as external devices. When the determined flow rate is smaller than the threshold value, the CPU turns off transistors to de-energize loads.

Flow rate detector

A threshold value is stored in a CPU using setting switches. When a fluid is introduced into a flow passage, it lowers the temperature of a first thermistor heated by a regulated constant-current source, increasing the output voltage of the first thermistor. A second thermistor outputs a voltage corresponding to the temperature of the fluid. A differential amplifier outputs a differential voltage between the output voltages of the first and second thermistors, and the differential voltage is converted by an A/D converter into a digital voltage that is applied to a CPU. The CPU refers to a data table stored in a memory to determine a flow rate of the fluid based on the digital differential voltage. When the determined flow rate is greater than the threshold value, the CPU turns on transistors to energize loads as external devices. When the determined flow rate is smaller than the threshold value, the CPU turns off transistors to de-energize loads.

A method of and a system for electrically processing vacuum pressure information, which is suitable for use in a vacuum unit. Pressure values are detected and a desired pressure value lower than the highest vacuum pressure value of the detected pressure values is displayed on a displaying device in digital form. The desired pressure value is stored in a storing device. Each of pressure values relative to vacuum, which are detected by a pressure detecting element held in front of a passage communicating with a vacuum port, is converted into a digital signal. The so-converted digital signal is digitally displayed on the displaying device. The desired pressure value stored in the storing device is compared with each of the detected pressure values relative to the vacuum, and information about faulty points is displayed on the displaying device based on the result of comparison.

Method of and system for electrically processing vacuum pressure

A positioning detector detects whether a workpiece has been positioned on a reference surface even when the pressure of a fluid supplied from a fluid pressure source and applied to the workpiece varies. A fluid is jetted from a nozzle toward a surface of the workpiece, and a back pressure of the fluid developed behind the nozzle is detected. A fluid pressure bridge is composed of the nozzle, a variable restriction, and a pair of fixed restrictions, and is connected to a semiconductor pressure sensor for detecting the difference between the back pressure and the pressure of a fluid vented through the variable restriction. The semiconductor pressure sensor has output terminals connected to a plurality of comparators for comparing the pressure difference detected by the semiconductor pressure sensor with respective different thresholds. Depending on the detected pressure difference, the comparators produce a different combination of output signals to selectively energize a plurality of light-emitting diodes for allowing the user to visually confirm the positioning of the workpiece with respect to the reference surface.

Positioning detector

In a vacuum unit which can electrically process information, a vacuum pressure value is detected by a detecting device and a desired pressure value is set by a setting device. The so-set desired pressure value is digitally displayed on a displaying device and stored in a storing device. The set desired pressure value is compared with the detected vacuum pressure value by a determining device. When the result of comparison is brought to a given value, it is determined that an unusual or improper state has been developed. When the set desired pressure value and the detected vacuum pressure value coincide with each other in a predetermined range, a predetermined signal is produced from an output device. The displaying device is provided with an adjusting device capable of adjusting the state of visual recognition of each pressure value.

Pressure information processing system suitable for use in a vacuum unit

A method and an apparatus for electrically processing vacuum pressure information in a vacuum unit. The apparatus basically comprises a vacuum supply mechanism, a detecting device, a determining device, a failure precognition signal generating device and a pressure setting-up device. In the apparatus, pressure values are first detected, and a desired pressure value lower than the maximum pressure value of the detected pressure values is digitally displayed on a display unit. Then, the desired pressure value is stored in a storage unit, and pressure values relative to vacuum, which are detected from the detecting device held in front of a passage which communicates with a vacuum port, are converted into digital signals. Thereafter, the digital signals thus converted are digitally displayed on the display unit. Further, the desired pressure value stored in the storage unit is compared with each of the detected pressure values. When they coincide with each other within a predetermined range, a predetermined signal is generated.

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Ibaraki-ken, Japan

Takashi Takebayashi