JPH0330120B2 - - Google Patents
Info
- Publication number
- JPH0330120B2 JPH0330120B2 JP59057009A JP5700984A JPH0330120B2 JP H0330120 B2 JPH0330120 B2 JP H0330120B2 JP 59057009 A JP59057009 A JP 59057009A JP 5700984 A JP5700984 A JP 5700984A JP H0330120 B2 JPH0330120 B2 JP H0330120B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- reference voltage
- output
- logarithmic
- light receiving
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000003321 amplification Effects 0.000 claims description 15
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 15
- 230000007257 malfunction Effects 0.000 claims description 4
- 230000002265 prevention Effects 0.000 claims description 2
- 238000009792 diffusion process Methods 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 230000020169 heat generation Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Geophysics And Detection Of Objects (AREA)
- Burglar Alarm Systems (AREA)
Description
【発明の詳細な説明】
〔技術分野〕
本発明は、産業機器、来客検知など民生用に用
いる拡散反射型光電スイツチに関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a diffuse reflection type photoelectric switch used for industrial equipment, visitor detection, and other consumer applications.
従来、拡散反射型光電スイツチは、第１図のよ
うに、被検知物体による受光レベル変化を検出す
る受光回路１の出力を第１の対数増巾回路２で対
数増巾し、比較回路３にて第１の対数増巾回路２
の出力電圧V1の基準電圧V2に対する大小を比較
判別して出力回路、誤動作防止手段、余裕表示手
段（いずれも図示せず）等を制御するようにして
いた。基準弁圧V2は、距離定回路４と第２の対
数増巾回路５とにより形成し、この第２の対数増
巾回路５は第１の対数増巾回路２と同等のものを
用いて温度ドリフトを有するようにしている。し
たがって周囲温度変化により第１の対数増巾回路
２の温度ドリフトが大きい場合でも第２の対数増
巾回路５の温度ドリフトにより補償するようにし
ている。
Conventionally, in a diffuse reflection type photoelectric switch, as shown in FIG. first logarithmic amplification circuit 2
The magnitude of the output voltage V 1 of the output voltage V 1 with respect to the reference voltage V 2 is compared and determined, and the output circuit, malfunction prevention means, margin display means (none of which are shown), etc. are controlled. The reference valve pressure V2 is formed by a distance constant circuit 4 and a second logarithmic amplification circuit 5. It is designed to have temperature drift. Therefore, even if the temperature drift of the first logarithmic amplifier circuit 2 is large due to a change in the ambient temperature, the temperature drift of the second logarithmic amplifier circuit 5 is used to compensate for it.
今、設定距離が短かい場合、即ち、被検知物体
が光電スイツチから近距離にある場合、帰還ダイ
オードD1に流れる電流はパルス波形で、そのデ
ユーテイが１％であるため、帰還ダイオードD1
に流れる電流による自己発熱に起因する第１の対
数増巾回路２の出力電圧V1の温度ドリフトは無
視できる。しかし、設定距離を短くするため、第
２図のように基準電圧V2を高くする必要があり、
帰還ダイオードD2には大電流が流れ、この電流
は直流であるため、帰還ダイオードD1の自己発
熱による第２の対数増巾回路５の出力電圧、つま
り基準電圧V2の温度ドリフトは無視できなくな
る。このことは、距離を設定したときと定常状態
になったとき、いいかえれば、可変抵抗VRを可
変にして距離を設定したときよりある一定時間経
過したときの設定距離が異なり、距離設定が困難
であることを意味する。 Now, when the set distance is short, that is, when the object to be detected is close to the photoelectric switch, the current flowing through the feedback diode D 1 is a pulse waveform and its duty is 1%, so the feedback diode D 1
The temperature drift of the output voltage V 1 of the first logarithmic amplification circuit 2 due to self-heating due to the current flowing in the logarithmic amplifier circuit 2 can be ignored. However, in order to shorten the setting distance, it is necessary to increase the reference voltage V 2 as shown in Figure 2.
A large current flows through the feedback diode D2 , and since this current is direct current, the temperature drift of the output voltage of the second logarithmic amplifier circuit 5, that is, the reference voltage V2, due to self-heating of the feedback diode D1 can be ignored. It disappears. This means that when the distance is set and when the steady state is reached, or in other words, the set distance is different after a certain period of time has elapsed than when the distance is set by changing the variable resistor VR, it is difficult to set the distance. It means something.
本発明の目的とするところは、第２の対数増巾
回路の帰還ダイオードの発熱による基準電圧の温
度ドリフトを補償し、安定した距離設定ができる
ようにし、温度ドリフトによる回路の誤動作を防
止することにある。
An object of the present invention is to compensate for the temperature drift of the reference voltage due to the heat generated by the feedback diode of the second logarithmic amplification circuit, to enable stable distance setting, and to prevent malfunction of the circuit due to temperature drift. It is in.
実施例
第３図において、６は自動利得調整回路で、距
離設定回路４の可変抵抗（図示せず）と連動して
決定される電圧V3と、設定距離に対応する基準
電圧V2とを入力する。電圧V3は自動利得調整回
路６の基準電圧となり、電圧Ｖ２は帰還ダイオー
ドD2の発熱によってドリフトする。他は第１図
の従来例と同様である。自動利得調整回路６で電
圧V2と電圧V3を比較し、帰還ダイオードD2での
ドリフトした値に対応して第１の対数増巾回路２
の利得を可変する。
Embodiment In FIG. 3, 6 is an automatic gain adjustment circuit that adjusts a voltage V 3 determined in conjunction with a variable resistor (not shown) of the distance setting circuit 4 and a reference voltage V 2 corresponding to the set distance. input. The voltage V 3 becomes the reference voltage of the automatic gain adjustment circuit 6, and the voltage V 2 drifts due to heat generation of the feedback diode D 2 . The rest is the same as the conventional example shown in FIG. The automatic gain adjustment circuit 6 compares the voltage V 2 and the voltage V 3 , and the first logarithmic amplification circuit 2 is adjusted according to the drifted value at the feedback diode D 2 .
variable the gain.
動 作
第４図ａは距離設定した瞬間の基準電圧V2と
第１の対数増巾回路２の出力電圧V1の波形を示
している。これは設定距離より遠方に被検知物体
がある場合で、基準電圧V2より出力電圧V1の波
形が高くない。したがって、この場合は被検知物
体を検知しない。つぎに、第４図ｂは、自動利得
調整をかけない場合で、基準電圧V2が帰還ダイ
オードD2の発熱のためΔVだけ低くなり、この場
合には出力電圧V1は同じであるため被検知物体
はあると判断してしまう。このことは前述のよう
に、距離設定時と定常状態になったときの基準電
圧V2の温度ドリフトΔV2により距離設定が困難
であることを示している。ここで、自動利得調整
をかけて基準電圧V2が低下した分だけ第４図ｃ
のように、第１の対数増巾回路２の利得を下げて
出力電圧V1を低下させる。これを距離と受光量
のグラフで示すと第５図ａ〜ｃのようになる。第
５図ａ〜ｃはそれぞれ第４図ａ〜ｃに対応する。
第５図ａ〜ｃより明らかなように、自動利得調整
をかけるこによって帰還ダイオードD2の発熱に
よる制定距離の変動はみられなくなる。いいかえ
れば、l1＝l3となる。又、自動利得調整回路６の
出力で第６図のように受光回路１の利得を制御し
ても同様であるが、受光回路１の利得を下げる
と、受光回路が発生するノイズに信号波形が埋も
れてしまう可能性がある。これは回路上での発生
ノイズは受光回路のノイズが支配的であるためで
ある。しかし、第１の対数増巾回路２のノイズが
信号波形に与える影響は極めて少なく、第１の対
数増巾回路２の利得を制御することで上述の問題
点は無視できる。更に、周囲温度によってV1，
V2がドリフトし、各対数増巾器２，５が飽和す
る可能性があるため、V1，V2の絶対的電位を検
知し、各対数増巾回路器２，５が飽和したいよう
に各対数増巾器２，５の利得を制御する。Operation FIG. 4a shows the waveforms of the reference voltage V 2 and the output voltage V 1 of the first logarithmic amplification circuit 2 at the moment when the distance is set. This occurs when the object to be detected is located further away than the set distance, and the waveform of the output voltage V 1 is not higher than the reference voltage V 2 . Therefore, in this case, the object to be detected is not detected. Next, FIG. 4b shows the case where automatic gain adjustment is not applied, and the reference voltage V 2 is lowered by ΔV due to the heat generated by the feedback diode D 2. In this case, the output voltage V 1 is the same, so the It is determined that there is a detected object. This indicates that, as described above, it is difficult to set the distance due to the temperature drift ΔV 2 of the reference voltage V 2 between when the distance is set and when the steady state is reached. Here, by applying automatic gain adjustment, the reference voltage V 2 is reduced by the amount shown in Figure 4c.
As in, the gain of the first logarithmic amplifier circuit 2 is lowered to lower the output voltage V1 . This is illustrated in graphs of distance and amount of received light as shown in Figures 5a to 5c. FIGS. 5a to 5c correspond to FIGS. 4a to 4c, respectively.
As is clear from FIGS. 5a to 5c, by applying automatic gain adjustment, the established distance does not fluctuate due to the heat generated by the feedback diode D2 . In other words, l 1 = l 3 . The same effect can be achieved by controlling the gain of the light receiving circuit 1 using the output of the automatic gain adjustment circuit 6 as shown in FIG. There is a possibility that it will be buried. This is because the noise generated on the circuit is dominated by the noise of the light receiving circuit. However, the influence of the noise of the first logarithmic amplifier circuit 2 on the signal waveform is extremely small, and by controlling the gain of the first logarithmic amplifier circuit 2, the above-mentioned problem can be ignored. Furthermore, depending on the ambient temperature, V 1 ,
Since V 2 may drift and each logarithmic amplifier 2, 5 may become saturated, the absolute potential of V 1 , V 2 is detected and each logarithmic amplifier 2, 5 is set as desired to saturate. The gain of each logarithmic amplifier 2, 5 is controlled.
上述のように本発明は、距離設定回路の出力と
基準電圧とを入力として比較し、基準電圧の温度
ドリフトに応じてそのドリフトを補償するため第
１の対数増巾回路又は受光回路の利得を制御する
自動利得調整回路を設けたから、第２の対数増巾
回路の帰還ダイオードの発熱による基準電圧の温
度ドリフトを補償できて安定した距離設定がで
き、温度ドリフトによる回路の誤動作を防止で
き、更に、第１の対数増巾回路の利得を制御する
ことによって回数全体のＳ／Ｎ比を向上でき、周
囲温度及び帰還ダイオードの発熱による各対数増
巾回路の出力電圧変動に起因する各対数増巾回路
の飽和を防止できるという効果を奏するものであ
る。
As described above, the present invention compares the output of the distance setting circuit with the reference voltage as an input, and adjusts the gain of the first logarithmic amplification circuit or the light receiving circuit in order to compensate for the temperature drift of the reference voltage. Since an automatic gain adjustment circuit is provided, it is possible to compensate for the temperature drift of the reference voltage due to the heat generated by the feedback diode of the second logarithmic amplification circuit, allowing stable distance setting, preventing circuit malfunctions due to temperature drift, and further By controlling the gain of the first logarithmic amplification circuit, the overall S/N ratio can be improved, and each logarithmic amplification due to the output voltage fluctuation of each logarithmic amplification circuit due to the ambient temperature and heat generation of the feedback diode can be improved. This has the effect of preventing saturation of the circuit.
第１図は従来の拡散反射型光電スイツチのブロ
ツク回路図、第２図は同上の特性図、第３図は本
発明の一実施例のブロツク回路図、第４図は同上
の動作説明図、第５図は同上の特性図、第６図は
本発明の他の実施例のブロツク回路図である。
１……受光回路、２……第１の対数増巾回路、
３……比較回路、４……距離設定回路、５……第
２の対数増巾回路、６……自動利得調整回路。
FIG. 1 is a block circuit diagram of a conventional diffuse reflection type photoelectric switch, FIG. 2 is a characteristic diagram of the same as above, FIG. 3 is a block circuit diagram of an embodiment of the present invention, and FIG. 4 is an explanatory diagram of the same as above. FIG. 5 is a characteristic diagram similar to the above, and FIG. 6 is a block circuit diagram of another embodiment of the present invention. 1... Light receiving circuit, 2... First logarithmic amplification circuit,
3... Comparison circuit, 4... Distance setting circuit, 5... Second logarithmic amplification circuit, 6... Automatic gain adjustment circuit.
Claims (1)
回路と、前記受光回路出力を対数増巾する第１の
対数増巾回路と、距離設定回路の出力により基準
電圧を出力する第２の対数増巾回路と、前記第１
の対数増巾回路の基準電圧に対する大小を比較判
別して出力回路、誤動作防止手段、余裕表示手段
等を制御する比較回路を具備した拡散反射型光電
スイツチにおいて、距離設定回路の出力と基準電
圧を入力として比較し、基準電圧の温度ドリフト
に応してそのドリフトを補償するための第１の対
数増巾回路又は受光回路の利得を制御する自動利
得調整回路を設けて成ることを特徴とする拡散反
射型光電スイツチ。1. A light receiving circuit that detects a change in the amount of light received by an object to be detected, a first logarithmic amplifying circuit that logarithmically amplifies the output of the light receiving circuit, and a second logarithmic amplifying circuit that outputs a reference voltage based on the output of the distance setting circuit. a circuit, and the first
In a diffuse reflection type photoelectric switch equipped with a comparison circuit that compares and determines the magnitude of the logarithmic amplification circuit with respect to the reference voltage and controls the output circuit, malfunction prevention means, margin display means, etc., the output of the distance setting circuit and the reference voltage are A diffusion device characterized in that it is provided with an automatic gain adjustment circuit that controls the gain of a first logarithmic amplification circuit or a light receiving circuit for comparing the reference voltage as an input and compensating for the temperature drift of the reference voltage according to the temperature drift thereof. Reflective photoelectric switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59057009A JPS60200107A (en) | 1984-03-24 | 1984-03-24 | Diffusion reflective type photoelectric switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59057009A JPS60200107A (en) | 1984-03-24 | 1984-03-24 | Diffusion reflective type photoelectric switch |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60200107A JPS60200107A (en) | 1985-10-09 |
| JPH0330120B2 true JPH0330120B2 (en) | 1991-04-26 |
Family
ID=13043446
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59057009A Granted JPS60200107A (en) | 1984-03-24 | 1984-03-24 | Diffusion reflective type photoelectric switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60200107A (en) |
-
1984
- 1984-03-24 JP JP59057009A patent/JPS60200107A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60200107A (en) | 1985-10-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5404585A (en) | Power detector that employs a feedback circuit to enable class B operation of a detector transistor | |
| US5652547A (en) | Current comparator automatic output control | |
| JPH0273682A (en) | Laser diode driving method and device | |
| JPH02113640A (en) | Automatic gain controller | |
| JPH05206771A (en) | Automatic output power control circuit | |
| US6509723B2 (en) | Constant voltage regulator, method of controlling the same, and electric device provided with the same | |
| US4914357A (en) | Temperature compensated foldback current limiting | |
| JPH0330120B2 (en) | ||
| JPH0580843B2 (en) | ||
| JP2915442B2 (en) | Automatic gain control method | |
| JP2674110B2 (en) | Temperature compensation circuit for avalanche photodiode bias circuit | |
| JP2845462B2 (en) | Optical receiving circuit | |
| JPS62164120A (en) | Constant current power supply circuit | |
| JPH0330119B2 (en) | ||
| JPH0158888B2 (en) | ||
| KR960001256Y1 (en) | Color Gain Automatic Control | |
| KR0136282Y1 (en) | Linear gain control system | |
| JPH0648980Y2 (en) | ALC circuit | |
| JPH0265515A (en) | Level control circuit | |
| JPS59218520A (en) | Automatic control circuit | |
| JPS6313525Y2 (en) | ||
| JPS62135083A (en) | Gain adjusting circuit for video signal | |
| JPH0595238A (en) | Automatic gain control circuit | |
| JP2542607B2 (en) | Automatic gain control circuit | |
| JP2874429B2 (en) | Recording current amplifier circuit |