JPS61181988A - Medium passage detection system - Google Patents

Abstract

PURPOSE:To make negligible noises and chatterings during the detection of medium passage, by judging that the ON/OFF ratio of information of a shift register exceeds the specified value with a computing circuit when the sensor output changes to detect the presence of the medium passage. CONSTITUTION:When a sensor output is inputted into a shift register 11, the shift register has, for example, a 7-bit shifting function and is shifted sequentially by a clock. In this case, as the response characteristic of the shift register is relatively slow, it will not respond to an extremely short noise and an instantaneous drop in the sensor output. But it is conceived that it responds to them in the form of a chattering waveform. A sampling is done and the output state of 7 bits is sent sequentially to an arithmetic circuit 12. The arithmetic circuit 12 computes output information for a certain time when the sensor output changes and when the information exceeds a specified value, it judges that a paper money exists to send ON to a J terminal of (FF)13 as input 1 while it sends OFF to a K terminal thereof as input 2 to deliver information to a CPU14 from the FF13. This can provide a quick response regardless of noises and breakage of the sensor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for detecting the presence or absence of a medium based on an output signal from a sensor provided on a medium conveyance path, and is particularly concerned with a method that is highly responsive to noise and chattering. This invention relates to a fast medium passage detection method.

[Conventional technology]

Conventionally, in transaction devices and the like, as shown in FIG.
Detects and inputs the sensor output to the boat of 0PU3,
The passage of banknotes is detected by checking disturbances in the sensor output due to noise and chattering caused by the CPU 3. Normally, in the sensor output, as shown in the same figure (b), an unstable part (■) occurs at the front end due to noise and chattering, so this is excluded by setting certain conditions and the determination is made by whether or not there is a stable part @ crab of a predetermined length. do.

FIG. 6 (6) is a flowchart showing the detection method by the CPU.

That is, a detection counter is reset, and if the sensor output is unstable, the reset is repeated, and after stabilization, the counter is counted and confirmed (OK) that it has reached a predetermined number of times, and it is assumed that the sensor output has been detected.

[Problem that the invention seeks to solve]

As shown in the flowchart above, the OPU detection method maintains a stable value for a certain number of sampling times, so if the sensor changes for some reason before the fixed number of sampling times is reached, the sensor value will change each time. Since the detection counter is reset and restarted, detection may take some time. In the case of a medium such as a banknote, even if the number of samplings during a certain period of time is mostly on when the front edge is detected, and there is a slight off due to chattering etc., this is clearly an input of a banknote. It is possible to judge.

An object of the present invention is to provide a medium passage detection method that makes it possible to ignore noise and chattering during medium passage detection.

[Means for solving problems]

In order to achieve the above object, the medium passage detection method of the present invention inputs the output signal from the sensor provided on the conveyance path to a multi-bit shift register, and performs sampling in the shift register for a fixed period of time. The output state of the sensor is sent to an arithmetic circuit, and the arithmetic circuit determines whether the ratio of on or off of information from the shift register when the sensor output changes exceeds a predetermined value, and detects whether or not the medium is passing. It is characterized by this.

[For production]

With the above configuration, by inputting the sensor output into a shift register instead of a counter, it does not respond to noise or sensor cracking, as will be described later. Then, the output state when the sensor output changes is sampled and passed to the arithmetic circuit. The arithmetic circuit determines that the on/off ratio exceeds a predetermined value and sends a medium passage detection signal to the CPU. In this way, we use a shift register with a slow response time to deal with short-term noise and sensor cracks, and to deal with chattering, we send the output status of the shift register to the arithmetic circuit, so that even if there is a slight turn-off, it will be ignored. The solution is to use a majority voting method that determines that it is on. In this way, the effects of noise and chatter at the front end of the medium are eliminated, and a fast passage detection response is possible.

〔Example〕

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention.

At the same time, the sensor output is input to the shift register 11.

The shift register has, for example, a 7-bit shift function and is sequentially shifted by a clock. In this case, since the response characteristic of the shift register is relatively slow, it does not respond to very short-term noise shown in FIG. However, there may be a case where a response occurs with a chattering waveform. Therefore, sampling including this chattering waveform is performed, and the 7-bit output state is sequentially sent to the arithmetic circuit 12. The arithmetic circuit 12 calculates the output information for a certain period of time when the sensor output changes, and if it is equal to or greater than a predetermined value, it is determined by majority voting that there is a banknote, and with ON as input 1, the flip 7tz knob (FF) 13 is activated. When there is no banknote in the J terminal, send OFF as input 2 to that terminal, and FF
13, pass the information to 90PU14.

The 0PU 14 counts the bill detection counter based on this information, checks a predetermined number of times, and determines whether the bill has passed.

〔Effect of the invention〕

As described above, according to the present invention, when detecting a medium such as a banknote, the sensor output is input to the shift register, thereby not responding to noise or sensor cracking. As for chattering, passing of the medium can be detected by sampling the output state of the shift register, passing it to an arithmetic circuit, and making a decision using a majority voting method. In this way,
Regardless of noise or sensor cracking, there is no need to repeatedly reset against chattering, and fast response can be achieved.

(α) to (6) are explanatory diagrams of the configuration and operation of the conventional example.
In the figure, 11 is a shift register, 12 is an arithmetic circuit, 13 is a flip-flop, and 14 is a CPU.

Claims (1)

[Claims] The output signal from the sensor provided on the medium transport path is input to a multi-bit shift register, and the output state shifted by sampling in the shift register for a certain period of time is sent to an arithmetic circuit, and the sensor output changes in the arithmetic circuit. A medium passage detection method characterized by determining whether the on/off ratio of information from a shift register exceeds a predetermined value and detecting whether or not a medium has passed.