70 results about "Loop detector" patented technology

A digital processor for use in a conveyor belt rip detector, which provides excitation signals at a selected frequency to inverted and noninverted sensor loops on a conveyor belt and then, detects corresponding received signals from the sensor loops. The digital processor then performs FFTs on the corresponding received signals to provide respective received signal frequency spectrums. Next magnitude and phase values of the selected frequency in the respective received signal frequency spectrums are used to determine a qualitative state of the sensor loops. The selected frequency has a lowest detected ambient noise level, and the magnitude value is a normalized magnitude value.

The present invention provides a smart shopping cart based on RFID, a shopping system based on RFID and an application method thereof. The smart shopping card comprises a cart body, and a touch screen, a microprocessor, a vehicle unit, a RFID identification antenna and a storage battery installed on the cart body; the storage battery, the RFID identification antenna and the vehicle unit are connected with the microprocessor; and the shopping system includes the smart shopping cart, a roadside unit, a loop sensor and a control center. The smart shopping cart based on RFID, the shopping system based on RFID and the application method thereof employ the vehicle unit, the roadside unit and the loop sensor for cooperation to make the payment process simple, and convenient and rapid compared to the traditional POS and cash payment; and moreover, through adoption of the RFID identification technology, the smart shopping cart based on RFID, the shopping system based on RFID and the application method thereof realize the automatic identification of goods information with no need for manually inputting numbers of goods and performing laser scanning so as to improve the efficiency.

The invention provides a high-voltage interlocking loop and a high-voltage interlocking loop detector, and relates to the technical field of high-voltage interlocking loop detection. A diagnosis controller is connected with the high-voltage interlocking loop and used for detecting the high-voltage interlocking loop, obtaining voltage information according to a diagnosis signal and an equivalent resistor and diagnosing fault state information according to the voltage information. The high-voltage interlocking loop is characterized in that the input end of one corresponding high-voltage connector is connected with a first low-value resistor and a first high-value resistor, the output end of the corresponding high-voltage connector is connected with a second low-value resistor, one end of a ground resistor is connected with a third low-value resistor and a second high-value resistor, and the other end of the ground resistor is grounded; the ground resistor, the low-value resistors and the high-value resistors are combined into the equivalent resistor through a loop resistor according to the loop connection state, and external connection with a power supply is achieved through the high-voltage connectors. The state of each high-voltage connector and the fault section of the high-voltage interlocking loop can be judged according to different pieces of voltage information, and the fault detection efficiency can be improved.

The invention discloses an optical fiber sensing probe for detecting gas and liquid and a preparation method of the optical fiber sensing probe. An adopted sensing optical fiber is provided with a micro-hole-channel structure, micro-holes are formed in one end side face of the sensing optical fiber, the other end side face of the sensing optical fiber is plated with a reflecting film, and then the optical fiber sensing probe for detecting the gas and liquid is formed. The optical fiber sensing probe can be combined with a Y-shaped optical fiber, an optical loop detector, an optical coupler and the like to form an optical fiber sensor, and can also be combined with a light source and a detector to form an optical fiber sensing system. The optical fiber sensing probe has the advantages that the integration degree is high, machining is easy, a sample pool is located inside the optical fiber, signal stability is high, and the length of a sensing section is adjustable. The optical fiber sensing probe can be used for detecting the gas and liquid in the various kinds of fields of environment detection, food detection and medical detection.

The invention relates to a method for detecting and controlling free loops by thin-strip continuous casting, which comprises the following steps that: infrared loop detectors are arranged at front and rear end points of the loops; angles alpha 1 and alpha 2 corresponding to the loop height at a central point of the width of a casting strip are measured by the loop detectors simultaneously to calculate a real value h of the loop height of the casting strip; after the loops are formed and reach a set target h0, the speed of pinch rollers is consistent with that of a cooling roller, a value of the loop quantity is constant basically, and the speed of the pinch rollers is changed correspondingly according to the change of the loop quantity in the process of forming the loops so as to form closed loop control; and the loop height h is changed by the change speed v of the pinch rollers, and the speed change rate delta v is determined according to the actual loop height and real-time speed of strip steel. In the method, an included angle between the forward direction of the strip steel at an outlet (a nip point) of the cooling roller and a vertical casting center line is kept within an ideal range in which cracks cannot be generated on the strip steel when the loops are changed due to the change of a thin-strip continuous casting process so as to prevent the quality defect of the casting strip due to the change of the loops and maintain casting continuity.

The invention relates to the technical field of interferometry, and discloses a heterodyne interference optical path structure based on optical fibers and a laser vibrometer. The optical path structure includes a first optical fiber coupler, an optical fiber frequency shifter, a second optical fiber coupler, an optical fiber loop detector and an optical transceiver, which are connected by opticalfibers and constitute a heterodyne interference loop. The laser vibrometer includes a measuring laser source, a balanced photoelectric detector and the optical path structure. The measuring laser source is connected with the input end of the first optical fiber coupler through an optical fiber, and the balanced photoelectric detector is connected with the output end of the second optical fiber coupler through an optical fiber. Through connection by optical fibers, the characteristics of small size and high reliability are achieved. Through the heterodyne interference optical path, the opticalpath system has high signal-to-noise ratio and anti-interference ability and can be used to measure geometric parameters such as length, displacement, straightness and flatness in the field of precision measurement.

Provided is a lighting ballast system and method for fluorescent lamps. The system and method utilize a lamp current control loop to control the light level of a fluorescent lamp. The ballast includes an open loop detector that recognizes an open current control loop as an indication of a fault or hazard condition, and causes the ballast to output a safe lamp voltage or no voltage. The fault or hazard condition may be, for example, a very high voltage at the lamp or very low current across the lamp. The ballast also includes a disable circuit that prevents the open loop detector from triggering at times when the loop is expected to be open such as during ignition and maintenance restarting of the lamp.

The present invention provides an image forming apparatus including an upstream conveying portion, a downstream conveying portion, and a loop detector, wherein the image forming apparatus further includes a driving portion which moves the contact portion to a projecting position where the sheet conveying path is in contact with a conveyed sheet and to a retracted position where the sheet conveying path is not in contact with the conveyed sheet, and a controlling portion which controls the driving portion such that the contact portion is moved from the projecting position to the retracted position before a tip end of a sheet which enters the sheet conveying path from the upstream conveying portion reaches the contact portion.