JPH05270728A - Condition discrimination device - Google Patents

Abstract

PURPOSE:To realize a condition discrimination device capable of acquiring a highly reliable condition discrimination result. CONSTITUTION:A condition discrimination device which discriminates conditional change of a measuring object in accordance with change of an output signal level of a sensor detecting the measuring object is constituted of an A/D converter 2 to convert an output signal of the sensor 1 to a digital signal, a threshold level computing part 3 to compute a threshold level to discriminate the conditional change of the measuring object in accordance with this output data of the A/D converter 2 and a comparison part 4 to compare the threshold level computed at this threshold level computing part 3 with the output data of the A/D converter 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a state identification device, and more specifically, it improves an erroneous operation due to an individual difference of a sensor in a device for detecting a state change of a measuring object based on a level change of an output signal of the sensor. It is about.

[0002]

2. Description of the Related Art For example, in a waveform recording apparatus using folding recording paper, an optical mark for changing the reflectance of light is provided in the vicinity of the perforation that also serves to fold and separate the recording paper, and the optical recording apparatus is equipped with this optical mark. An optical sensor that detects the mark as a change in the photoelectric conversion signal level is provided,
When the operator presses the page index feed key, the optical sensor detects the optical mark to control the recording paper feed operation, and the recording start position can always be set to a fixed positional relationship with the perforation. Has been done.

By the way, conventionally, in processing the output signal of such an optical sensor, the threshold level with respect to the output signal level of the optical sensor for detecting the presence or absence of an optical mark is fixed to a predetermined value obtained experimentally. It was done in advance.

[0004]

However, the magnitude of the change in the output signal level of the optical sensor corresponding to the presence or absence of the optical mark is 1 when the output signal level in the absence of the optical mark is 1.
Then, the output signal level when there is an optical mark is about 0.8. The optical sensor has individual differences and changes over time.

From these, when the threshold level with respect to the output signal level of the optical sensor is fixed to a constant value, the optical mark is not recognized or there is no optical mark when the page cue feed key is pressed. However, it may be mistaken for an optical mark,
There is a problem of low reliability. The present invention solves such a problem, and an object thereof is to realize a state identification device which can obtain a highly reliable state identification result.

[0006]

SUMMARY OF THE INVENTION In order to solve such problems, the present invention provides a state in which a state change of an object to be measured is identified based on a change in output signal level of a sensor for detecting the object to be measured. In the identification device, an A / D converter for converting the output signal of the sensor into a digital signal, and the A / D converter
A threshold level calculating section for calculating a threshold level for identifying a state change of the measuring object based on output data of the converter, a threshold level calculated by the threshold level calculating section and the A / D.
And a comparison unit for comparing the output data of the converter.

[0007]

The threshold level calculation unit reflects the value of the output data of the A / D converter obtained by converting the output signal of the sensor when calculating the threshold level. As a result, the threshold level dynamically changes with changes in the characteristics of the sensor, and a highly reliable state identification result can be obtained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention, showing an example of page cueing of recording paper by a combination of an optical mark and a photosensor in a waveform recording apparatus using folding recording paper. In the figure, 1 is a photo sensor used as a sensor, and the output signal thereof is an A / D converter 2
Has been entered in. Reference numeral 3 is a threshold level calculation unit, which calculates a threshold level for identifying a change in the state of the measurement object based on the output data of the A / D converter 2. Reference numeral 4 denotes a comparison unit. One of the input terminals receives the threshold level calculated by the threshold level calculation unit 3, and the other input terminal receives the output data of the A / D converter 2. ..

FIG. 2 is a flow chart for explaining the operation of FIG. The state of the measuring object is converted into an analog output voltage by the photo sensor 1 (step). The analog output voltage of the photo sensor 1 is applied to the A / D converter 2 and converted into a digital value (step). A / D
The output data of the converter 2 is input to the comparison unit 4 and compared with the threshold level at that time (step). When the digital value> threshold level, it is determined that there is no optical mark A (step). After that, the threshold level calculation unit 3
Calculates the digital value × constant, and inputs a new threshold level to the comparison unit 4 in preparation for the next comparison operation (step). Here, the constant is set to 0.8, for example. As a result, 80% of the output voltage in the state A is dynamically changed and set as the threshold level for the next comparison operation. After that, the operation from step is repeatedly executed. In the step, if the digital value <threshold level, it is determined that the state B has an optical mark (step), and the operation from the step is repeated without changing the threshold level. Here, by setting the initial value of the threshold level to the minimum value of the output voltage when the photosensor 1 is normal, it is possible to detect the defect of the photosensor 1.

With such a configuration, the threshold level dynamically changes in accordance with the change in the characteristics of the photosensor 1, which is more reliable than the conventional one in which the threshold level is fixed. A highly accurate state identification result is obtained. In calculating the new threshold level in the step of FIG. 2, the average value of the output data of the A / D converter 2 may be calculated a plurality of times in the past. In this case, it is possible to realize a device having high reliability against noise and the like.

Further, in the above-described embodiment, an example of performing page cueing of the folding recording paper is shown, but it is also applicable to various devices for identifying the state of the measuring object according to the output signal of the sensor.

[0012]

As described above, according to the present invention,
It is possible to realize a state identification device that can obtain a highly reliable state identification result that is unlikely to be affected by variations in characteristics of individual sensors and temporal changes in characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of FIG.

[Explanation of symbols]

 1 Photosensor (sensor) 2 A / D converter 3 Threshold level calculation unit 4 Comparison unit

Claims (1)

[Claims] 1. A state identification device for identifying a state change of a measurement object based on a change of an output signal level of a sensor for detecting the measurement object, the A / D converter converting an output signal of the sensor into a digital signal. And a threshold level calculation unit for calculating a threshold level for identifying a change in the state of the measuring object based on the output data of the A / D converter, and a threshold level calculated by the threshold level calculation unit. A state identification device comprising: a comparison unit that compares the output data of the A / D converter.