JPS6336263Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention is based on the property that infrared light is irradiated onto an object to be measured, and after interacting with the object, it is guided to a sensor in a time-series manner. The present invention relates to a measuring device that detects a plurality of signals with different values, performs desired calculations using these detection signals, and measures the amount of water contained in an object to be measured.

<Prior art> Fig. 1 is an explanatory diagram of the configuration of a conventional device, and Fig. 2 is a diagram showing the configuration of a conventional device.
FIG. 3 is a partial sectional view of the conventional device shown in the figure, and FIG. 3 is a time chart of signals in the conventional device shown in FIG.

In FIG. 1, 10 is an upper head, 20 is a lower head disposed opposite to the upper head 10, 30 is a sheet-like object to be measured such as paper that flows through the gap formed by these upper and lower heads, 13, 22 upper head 1
0 and a reflective film provided on the opposing surfaces of the lower head 20,
11 and 12 are irradiation windows provided in the upper head;
They are provided at intervals in the paper flow direction indicated by arrows in FIG. Reference numeral 21 denotes an entrance window provided in the lower head 20 facing the irradiation window 12.

The upper head 10 has a rotating sector 40 and a lamp 5.
0, lenses 51 and 52, and a reflecting mirror 53. The rotating sector 40 supports a disc-shaped plate 41,
Two through holes are provided in the plate surface of this plate, and one through hole is provided with an optical filter 42 for reference light that selectively transmits a wavelength range of approximately 1.80 μm, and the other through hole is provided with an optical filter 42 for a reference light that selectively transmits a wavelength range of approximately 1.95 μm. An optical filter 43 for measuring light is provided that selectively transmits light in the μm wavelength range. In the upper head 10, the lamp 50→lens 51→
An optical path from the irradiation window 11 to the paper 30 and an optical path from the lamp 50 to the reflecting mirror 53 to the lens 52 to the irradiation window 12 to the paper 30 are formed. 44-4 in Figure 2
Reference numeral 7 denotes a notch provided at the peripheral edge of the plate 41, whereby when the optical filters 42 and 43 pass through the irradiation window 11 or 12, a synchronization signal is generated in cooperation with a synchronization signal generation section to be described later. let

D ₁ and Q ₃ are light emitting diodes and phototransistors placed across the notches 44 to 47 at the peripheral edge of the plate 41 of the rotating sector 40, and together with the amplifier A ₄ and the signal converter A ₅ , they function as a synchronizing signal generator. It consists of

The lower head 20 includes a lens 54, a sensor SE, and a signal detection section. The signal detection section includes an amplifier A ₁ to which a detection signal from SESA SE is given, an AG circuit A ₆ ,
It includes sample-and-hold circuits SH ₁ to SH ₄ operated by signals e ₁ to e ₄ from the synchronization signal generator. The AGC circuit A ₆ consists of an amplifier A ₂ to which the output E ₁ of the amplifier A ₁ is applied via a resistor R ₁ , a field effect transistor Q ₁ connected between the input terminal of this amplifier and a reference potential, and the output of the amplifier A ₂ A DC blocking capacitor C ₁ connected to the side, a field effect transistor A 2 connected between this capacitor and a reference potential and discharging the charge of this capacitor at regular intervals by a signal e ₅ from the synchronization signal generator, _and a resistor. The output Rn of the sample-and-hold circuit SH ₄ applied through R 2 and the reference signal Vs applied through the resistor R ₃ are added together, and a capacitor _{C 2 is} connected between the input and output.
an integrating amplifier A ₃ whose output is applied to the gate of a field effect transistor Q ₁ .

Next, the operation of the conventional device configured as described above will be explained with reference to the time charts shown in FIGS. 2 and 3. Optical filters 42, 4 of rotating sector 40
3 and the irradiation windows 11 and 12 are as shown in FIG. 2A. That is, while the rotating sector 40 is rotating, the optical filters 42 and 43 are exposed to the irradiation windows 11,
12 sequentially, and when an optical filter is located in one of the optical paths, the other optical path passes through the rotating sector 4.
The structure is such that it is blocked by a plate 41 of 0. Board 41
When the optical filter 42 is above the irradiation window ₁₁ , as shown in FIG.
It is located in the optical path consisting of Q ₃ and excites phototransistor Q ₃ to generate a synchronization signal. Similarly, the notch 45 generates a synchronization signal when the optical filter 43 is above the irradiation window 11, the notch 46 generates a sync signal when the optical filter 42 is above the irradiation window 12, and the notch 47 generates a sync signal when the optical filter 42 is above the irradiation window 12. When the optical filter 43 is above the irradiation window 12, a synchronization signal is generated.

When the optical filter 42 is above the irradiation windows 11 and 12, the paper 30 is irradiated with comparative light (R light) of approximately 1.80 μm that is not attenuated by moisture, and the optical filter 43 is above the irradiation windows 11 and 12. At one time, approx.
The paper 30 is irradiated with 1.95 μm measurement light (M light).
After the R light and M light interact with the paper 30, they are detected by the sensor SE, and are provided to the sample and hold circuits _SH1 to _SH4 via the AGC circuit _A6 .
The signals from the AGC circuit _A6 are the signals R'n, _M'n , R't, and
This is a time series signal of M′t. Here, the signals R′n, M′n
are the R light and M light emitted from the irradiation window 11, and after having many interactions with the paper 30, the sensor
This is a signal corresponding to the amount of R light and M light that reaches the SE. Furthermore, the signals R't and M't are the R and M lights emitted from the irradiation window 12, and the R and M lights reach the sensor SE with a small number of interactions (sometimes only transmission) with the paper 30. This is a signal corresponding to the amount of light.

The synchronizing signal from the synchronizing signal generator is a time-series signal of signals e' ₄ , e' ₃ , e' ₂ and e' ₁ shown by waveform e ₀ in FIG. Signals e′ ₄ , e′ ₃ , e′ ₂ and e′ ₁ are synchronized with signal components R′n, M′n, R′t and M′t in signal E ₂ , respectively, and each synchronization signal e The width of ′ ₄ ~ e′ ₁ is
This corresponds to the notch width W ₁ of the notches 44 to 47. These time series signals e′ ₄ to e′ ₁ are sent to the third signal converter A ₅ .
Waveforms e ₄ , e ₃ , e ₂ and
It is converted into a signal indicated by e ₁ and becomes a signal that controls the sample-and-hold circuits SH ₄ to SH ₁ . The sample and hold circuits SH ₄ to SH ₁ are controlled by these signals, and the signal components R′n, _M′n , R′t, and M′t are
signals from each sample-and-hold circuit.
Outputs Rn, Mn, Rt and Mt (only signal Mn is shown in FIG. 3). These signals are given to a calculation section at the next stage, and a signal corresponding to the amount of moisture contained in the paper 30 is calculated.

In the AGC circuit _A6 , the signal Rn based on the comparison light is compared with the reference signal Vs, and the drain-source resistance of the field effect transistor _Q1 is controlled to perform gain control so that they match. Also,
If the base of signal E ₂ fluctuates, it will cause an error, so signal e ₅ is connected to a field effect transistor at a constant period.
Base compensation is performed by connecting the capacitor C ₁ to the reference _potential .

<Problem to be solved by the invention> The signal e ₅ is generated by providing a timer in the signal converter A ₅ and determining the timing when the optical filters 42 and 43 are not above the irradiation windows 11 and 12, for example, when the light is emitted between the notches 44 and 47. It was designed to be generated when passing through the diode _D1 and phototransistor _Q3 . For this reason, a timer that operates accurately and stably is required.
Usually, a synchronous motor is used as the drive source for the rotating sector 40, so it is necessary to change the specifications of the timer depending on the power frequency of the location where the measuring device is used. Therefore, manufacturers of moisture meters are required to prepare two types of timers that are highly accurate and operate stably, which causes high costs.

The present invention has been devised in view of these points, and its purpose is to provide a measuring device equipped with a synchronization signal generator that is independent of the power supply frequency and does not require a highly accurate timer.

<Means for Solving the Problems> The configuration of the present invention is such that in the measuring device, a notch wider than these notches is formed between the notches for generating a synchronization signal on the peripheral edge of the rotating sector, and A time series signal consisting of one wide pulse signal and multiple narrow synchronization signals synchronized with the irradiation state is generated for each rotation, and this time series signal is applied to a timer including a one-shot multivibrator and a logic circuit. , when the wide pulse is applied, a pulse signal that is narrower than the wide pulse and wider than the synchronization signal is generated, and the signal is synchronized with the wide pulse signal by logic between the pulse signal and the time series signal. is generated, and base compensation of the DC blocking capacitor is performed based on this signal.

<Operation> The above technical means operates as follows. That is,
A control signal for base compensation of the capacitor is generated by a wide notch provided at the periphery of the rotating sector, and this signal is converted from a time series signal by a timer including a one-shot multivibrator and a logic circuit. Since they are separated, a high-precision timer is not required, and stable control can be performed regardless of changes in the drive power frequency of the rotating sector.

<Examples> Examples of the present invention will be described below with reference to the drawings. FIG. 5 shows a rotating sector in an apparatus according to an embodiment of the present invention, in which figure A is a front view and figure B is a plan view. 6th
The figure is an explanatory diagram of the configuration of the signal converter in the apparatus according to the embodiment of the present invention. In FIG. 5, the same reference numerals as those in FIG. 2 have the same meanings, so the explanation here will be omitted. 48 is the notch 4
4 and 47, the notch width of notches 44 to 47
The notch has a notch width _W2 larger than _W1 .
60 is a photointerrupter with a U-shaped cross section that incorporates a light emitting diode and a phototransistor;
It is installed so as to sandwich the peripheral edge of the plate 41, and each time the notches 44 to 48 pass the position of the photo interrupter 60, time series signals e' ₅ to e' ₁ corresponding to the notches 48 and 44 to 47 are obtained. It's becoming like that.

In the signal converter shown in FIG. 6, T _i is the signal e ₀
The input terminal TM to which is applied is a timer that includes a one-shot multivibrator MM and a gate _A7 and inputs a signal _e0 . CO is a counter that is given the signal _e0 and is reset by the output of the timer TM, DE is a decoder that is given each bit output from the counter CO and is reset by the output of the timer TM, and GE is A gate consisting of gates A ₈ to _{A 11} takes the signal e ₀ and the output of the decoder DE as input, T ₀₁ to _{T 04} are output terminals for sending the outputs of gates A ₈ to _{A 11} to the outside, and T ₀₅ is a timer. TM
This is an output terminal for sending the output to the outside.

Next, the operation of the apparatus according to the present invention will be explained with reference to the time chart shown in FIG. The detection signal from sensor SE is a signal similar to that of a conventional moisture meter, as shown in waveform _E2 . On the other hand, the detection signal by the photo interrupter 60 has a waveform _e0 , a signal _e'5 having a wide pulse width _T2 , and signals _e'4 , _e'3 , _{e'2 ,} and e having a narrow pulse width T1. ′ ₁ time series signal. The pulse widths T ₂ and T ₁ are determined by the notches 48 and 4 of the plate 41.
It corresponds to notch widths W ₂ and W ₁ of 4 to 47.

The multivibrator MM operates on the falling edge of the signal e′ ₅ ~ e′ ₁ , its time constant T ₀ is chosen such that T ₁ < T ₀ < T ₂ , and it is metastable only for wide pulses with pulse width T ₁ . When the pulse width _T1 is narrow, the count is not increased and returns to the original stable point midway, producing an output as shown in waveform _e6 . Gate A ₇ receives signals e ₀ and e ₆ and has a waveform synchronized with wide pulse width signal e′ ₅ .
e Outputs only the signal shown in ₅ .

The counter CO is reset by the output e ₅ from the timer TM and pulse signals e' ₄ , e' ₃ , e' ₂ and e' ₁
is counted, the counted value is given to the decoder DE for decoding, the decoded signal of signal e′ ₄ is given to gate A ₁₁ , and the decoded signal of signal e′ ₃ is decoded.
A ₁₀ , a decode signal of signal e' ₂ is applied to gate A ₉ , and a decode signal of signal e' ₁ is applied to gate A ₈ . A time series signal e ₀ is given to the other input terminal of each gate, a signal e 4 synchronized with the signal e′ ₄ is obtained from the gate A ₁₁ , and a signal e ₄ synchronized with the signal e′ ₃ is obtained from the gate A ₁₀ . A signal e ₃ is obtained from the gate A 9, and a signal e 3 is obtained from the gate A ₉ .
A signal e ₂ synchronized with e' ₂ is obtained, and a signal e ₁ synchronized with signal e' ₁ is obtained from gate A ₈ . These signals e ₄ to e ₁ are used as signals to control the sample and hold circuits SH ₄ to _{SH 1} of the device shown in FIG. ₁ , and the signal components R'n, M'n, R't, and M′t are separated.

On the other hand, the signal e ₅ is applied to the gate of the field effect transistor Q ₂ of the device shown in FIG _.
is connected to the reference potential every time the rotating sector 40 rotates once, thereby performing base compensation.

<Effects of the invention> According to the invention, a signal for controlling the discharge of the capacitor is generated by a wide notch provided at the periphery of the rotating sector, and this signal is generated from the time-series signal by one-shot multiplexing. Since separation is performed using a simple timer composed of a vibrator and a logic circuit, a highly accurate timer is not required, and stable control can be performed regardless of changes in the drive power frequency of the rotating sector.

In addition, as a secondary effect, since the plate 41 of the rotating sector 40 has a wide notch 48 at the peripheral edge,
During maintenance and inspection of the rotating sector 40, align the notch 48 with the position of the photo interrupter 60 and remove the plate 41.
can be removed in the direction of the rotation axis, rotating sector 4
There is an advantage that maintenance and inspection of 0 etc. can be performed easily.

In the above embodiment, a decoder is used as a signal converter, but other means, such as a shift register with serial and parallel outputs, can also be used.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of the conventional device, and Fig. 2 A, B, and C represent the A, Ro, and H parts in Fig. 1.
3 is a time chart of signals in the conventional device shown in FIG. 1, and FIG. 4 is a time chart of signals in a moisture meter according to an embodiment of the present invention.
FIG. 5 is an explanatory diagram of the configuration of a rotating sector of a moisture meter according to an embodiment of the present invention, in which A is a front view, B is a plan view, and FIG.
FIG. 6 is an explanatory diagram of the configuration of a signal converter of a moisture meter according to an embodiment of the present invention. 40... Rotating sector, 41... Plate, 42, 43... Optical filter, 44-47... Narrow notch, 48
...wide notch, 60...photo interrupter,
TM...Timer, CO...Counter, DE...Decoder,
GE...Gate, MM...One-shot multivibrator.

Claims (1)

[Scope of utility model registration request] An upper head and a lower head are arranged facing each other, a sheet-like object to be measured is passed through the gap between the upper and lower heads, and a light source and a plurality of optical filters that selectively transmit light in different wavelength ranges are installed in the upper head. A rotary sector is provided with a notch provided on the peripheral edge thereof to generate a synchronization signal when the optical filter is on the irradiation window, and a photo interrupter for detecting the notch, and the lower head is provided with a rotary sector that is provided with a notch that generates a synchronization signal when the optical filter is on the irradiation window. A sensor for detecting incident light transmitted and scattered by the sheet-like object to be measured based on light, and a signal detection section including an AGC circuit and a DC blocking capacitor are provided, and a detection signal given in time series by the sensor is transmitted to the capacitor. The signal component is separated from the AC signal that passed through this capacitor using the synchronization signal, and the water content in the object to be measured is determined by calculation based on these signal components. In the measuring device, the AGC circuit is controlled based on a reference signal in the rotating sector so that this signal becomes constant, and the DC blocking capacitor is connected to a reference potential at a constant cycle for base compensation. A notch wider than these notches is formed between the notches for generating a synchronization signal, and each revolution of the rotation sector consists of one wide pulse signal and a plurality of narrow synchronization signals synchronized with the irradiation state. generating a series signal and applying the time series signal to a timer including a one-shot multivibrator and a logic circuit to generate a pulse signal narrower than the wide pulse and wider than the synchronization signal when the wide pulse is applied; A signal synchronized with the wide pulse signal is generated by logic between the pulse signal and the time series signal, and base compensation of the DC blocking capacitor is performed based on this signal. Device.