Technical Description

Transcription

1 Overview are differentiated depending on applied edia. Light, one of the edia, is also utilized for a which is called a photoelectric. It is a non-contact type which is applicable to sensing presence, passing, size, color and brightness of the object. Classification By Method s can be classified into three categories depending on sensing type. Through-bea photoelectric Through-bea bea type is to detect a by using the difference of light intensity depending on presence of with placing an eitter and a receiver face to face. Long sensing distance is available and it is not affected by background. Eitted light Retroreflective photoelectric Retroreflective type(standard type) Retroreflective type uses a photoelectric which is integrated with eitter and receiver, and a reflector with high light radiant in order to detect a by coparing difference of light aount deterined by the presence of between the and reflector. Eitted light Eitted light Using highly reflective objects is liited but it depends on install ethod, it could be available to use. Retroreflective type(built-in polarized filter) Like the standard type of retroreflective photoelectric, polarized filter type uses a photoelectric which is integrated with eitter and receiver and reflector. The eitter part and receiver part in the have each polarized filter for receiving reflected light fro the reflector which ake the light polarized at 90. filter A Eitted part Horizontal polarized filter filter B part Reflective surface filter A Vertical polarized filter filter B Diffuse reflective photoelectric Diffuse reflective is to detect a by direct reflection off the object. (eitter / receiver in one body) Standard diffuse reflective type Light source is diffused after passing the lens, detects a by coparing difference of light aount which depends on size, color and brightness of the object. Narrow bea type Narrowed bea spot size after passing the lens has little effect on background. It is suitable for sensing in narrow space or sensing sall size of the object. Convergent reflective type Convergent reflective type sensed the liited area (checked part) where optical source is crossed. In the figure below, the sensing at can be detected while the at cannot. Due to detecting the liited area by optical source, there is little effect by background but it is not siple to odify sensing distance and sensing in a specific area (within 50). BGS(background suppression) type It detects range of set distance which is applied the algorith of triangulation principle which is for easuring the place where the reflected light fors an iage on the receiving or the optical syste. Also it has little effect by size, color and surface condition of the sensing and no effect on the background. Strong at teperature, power and voltage changes and available detect to sensing distance over 100. Triangulation : light fors an iage on the receiving light after it is reflected on the sensing. In case sensing is located at, the sae aount of reflected light will be received on both N and F part of receiving. In case sensing is located closer, larger aount of reflected light will be received on N part and less aount of light on F part. In case sensing is located further, both N and F part will receive the reflected light vice versa. Therefore, sensing distance can be deterined with calculating the aount of reflected light on both parts of receiving (two-segent photodiode). N F (Two-segent photodiode) LED Received part Eitted part range Aount of incident light on F = Aount of incident light on F + range Aount of incident light on N range Setting distance & A-91

2 Glossary LED : Light Diode A seiconductor diode eits light when an electric current passes through it. The color and brightness of LED is deterined by the coponent, construction ratio, ipurities of PN junction for iproving single crystal which is ade with galliu(ga) to ixed crystal. Infrared LED : Using P-N junction for GaAs Red LED : Adding ipurities Zn, O to GaP Green LED : GaP/Green light eitting/ Yellowish green eitting is used due to low efficiency. Yellowish green LED : Adding N to GaP / Higher eitting efficiency than Green eitting. The ost coon eitting for photoelectric is IRED having high eitting efficiency and large outputs. Red or green LED is also frequently used according to applications. Photo diode A photo diode is a type of diode capable of converting light into either current or voltage when light reached to P layer. PN or PIN junction used. Si is generally used for seiconductor. PIN photodiode is coonly used as receiving s to catch optical signal with high response and frequency. Applicable to photoelectric s receiving s, PCM transission for optical counication, and TV/ VTR reote controller s receiving parts. Photo transistor Copared to photo diodes, photo transistor has aplifying action by transistor. Control easily due to high receiving sensitivity for Base current. Thus it is available in a wide range of photoelectric s. The sensing serves as a reference for easuring basic perforance. Retrorefl ective Diffuse reflective Through-bea Hysteresis (reflective type) Distance difference between operating distance and returning distance. Response tie The tie lag between light received point and the point on which output operation becoes ON.(Light ON) Generally, response tie is represented as operation tie (Ton). [Operating tie (Ton) Returning tie (Toff)] Output / Interrupted light ON OFF Light ON out out Returning distance Operating distance Dark ON ON OFF Hysteresis out Bea angle Angle range for noral sensing by the s. Operating tie (Ton) Returning tie (Toff) Major Features s bea angle Operation ode Light ON Output switching s (transistor or Relay) becoe ON when the receiver receives eitting light fro the eitters. Dark ON Output switching s (transistor or Relay) becoe ON when the receiver does not receive eitting light fro the eitters. Non-contact detection is a non-contact type which does not have any ipact on the sensing. Wide range of sensing Applicable to a wide range of aterials including transparent glass, etal, plastic, wood and liquid. High speed response tie Use light as the ediu, it is able to detect the oving object with high speed. Superior distinction perforance Use several characteristics of light, various kinds of s are developed. They are able to detect presence, passing, size, color, and brightness of the sensing. Easy to control application environent Easy to control sensing range and environent of photoelectric by using lens such as half irror, shield boards, slit. A-92

3 Low influence fro agnetic field and vibration Use light when photoelectric detect the sensing, it is less affected by agnetic and vibration. Color identification The rate at which an object reflects or absorbs light depends on both the wavelength of the eitted light and the color of the object. This property can be used to detect colors. Objects Of Diffuse Reflective Type distance according to color Relative sensing distance(%) It shows ratio of sensing object each detection distance based on non-glossy white paper is 100%. Relative sensing distance depends on the odel and sensing object size. Convergent reflective type is not affected by color or aterial within range of sensing distance as specified in chart. distance and range against the sensing condition The reflectivity of the sensing surface is higher, the sensing distance is longer. The size of the sensing is bigger, the sensing distance is longer. The rate of reflection of the sensing is lower, the sensing area is ore narrow. However in the case of white non-glossy paper, it has lower reflectivity than glossy SUS or aluinu, but the property of sensing area is better by diffused reflection of the surface of the white paper. 70 A B C D E F G H I J K L A: Non-glossy white paper(standard) B: Corrugated card board with yellow color C: Veneer board D: Non-glossy black paper(brightness 3) E: Bakelite board with yellow color Acrylic board (black) Vinyl resin (red) F: Vinyl resin (orange) G: Rubber board H: Aluinu board I: Reflective bar J: Rusty steel bar Ø10 K: Black cloth (towel) L: Dark Blue cloth(towel) Feature Data The following describes about the feature data. Exaple of parallel shifting characteristic (Through-bea type) This characteristic for through-bea type, indicates about width of light for the eitter. As shown in the figure, the receiver 1, 2, 4 operate norally but the receiver No. 3 does not operate norally because it is out of the width of light. Refer to this data when placing several s in parallel, it is able to prevent utual inference. In case installing the receiver at 9 point (as 2 in the figure), there ust be 110 interval between each unit in order to prevent utual interference. distance characteristic (Diffuse reflective type) This is featured as data of diffuse reflective type s sae as the parallel shifting characteristic. Angle characteristic (Through-bea type, Retroreflective type) After fixing the eitter(or reflector), and the receiver() oves towards the center axis fro right or left, up or down until operation becoes OFF. distance L () angle characteristic (Retroreflective type) Move a reflector towards center axis fro right or left, up or down with fixing the receiver until operation becoes OFF. Retroreflective type ❶ Left ❷ Right ❹ ❸ Operation position() : distance, : angle Retroreflective type : distance, : angle & A-93

4 Proper Usage Precaution for proper installation Make sure to secure sensing space(sensing stability) when selecting and installing the. Make sure that diaeter of lens (Ø) is saller than sensing when selecting the. If there are any possibilities to be daaged by sensing s, use protection covers for protecting photoelectric s. In case the is applied to high frequency achines, such as ultrasonic welding achine, etc, insulate the and high frequency achines using insulating boards to prevent alfunction fro induced current. Keep the cable as short as possible. In case of cable extension, ake sure that thickness of the cable shall be over Be careful of voltage drop. is generally applied for achine, or equipent. It is easy to have the effect of vibration or shock. In order to prevent this effect, please following countereasures before using. 1 Do not ake s ain body touch the sensing directly. 2 Use sturdy aterial supports in order not to be affected by vibration or shock. 3 Tighten fixed bracket s bolts and nuts. If photoelectric lens are dirty by dust, clean with a dried towel softly. Do not use organic solvent, such as thinners, etc. Avoid dust or any corrosion causing environents. Countereasures for utual interference In the case of using the photoelectric s closely, you should ake countereasures because of interference which affects to other s operation. Through-bea type 1 Increase the separation distance with referring to parallel shifting feature data. 2 or ore 2 or ore 2 Place the eitter and the receiver alternately. In this case, if the photo is installed closely like [Figure 1], it can cause alfunction. User needs to install a shield like [Figure 2]. 3 Narrow the light by using slits on the receiver. [Figure 1] [Figure 2] Slit(BYD3M-ST) Diffuse reflective type, convergent reflective type 1 Check the install distance which has no interference at the sensing area characteristics of the. Install the with the 2 ties longer operating position(l1) than sensing distance. 2 Install shield between s. Placing a shield L distance L Left Right area [Parallel shifting characteristic feature data] 2 or ore distance L Left Right L area [ area feature data] A-94

5 Influence of surroundings Through-bea type Eitted light is not copletely interrupted by a sensing because soe aount of eitted light gets reflected light fro the ounting board and enters into the receiver. al axis 2. Attach slits or protection cover on the receiver. Disturbing light Slit [Countereasure 1] [Countereasure 2] al axis Diffuse reflective type 1. Effect of install surface In case a diffuse reflective is ounted on a rough ounting plate, the reflected light causes photoelectric s alfunction. For preventing this, please ount the with bracket. Mounting board 2. Effect of the surrounding object Even though the surrounding object such as wall is far apart fro the sensing, the object is able to affect the detection. Countereasure: 1 Paint the background in black color to reduce reflected light. 2 Increase the distance fro the background. 3 Select convergent reflective type. Influence of disturbing light There are two types of photoelectric s which are odulated type and non-odulated type. Modulated type is not affected by noral disturbing light. But it can be affected by strong disturbing light or odulated disturbing light. Strong disturbing light : Direct rays of sunlight Modulated disturbing light : Arc welding spark, Inverter fluorescent. 1. Set the optical axis of the receiver ore than 30 difference with the entering light direction of disturbing light. (Set exceed the range of light width) Operation power and grounding In case of coercial power, use power supply with low noise/voltage variations. Avoid using the unit around the power generators or high voltage lines. Do not connect high voltage power source line and s cable power line together. It ay cause product daage or alfunction. Please wire lines separately. < Iproper connections > In case of DC power photoelectric s, use insulation transforer for rectified power supply with ±10% ripple. Secondary Priary In case power is supplied fro switching ode power supply, ensure that the frae ground (F.G.) terinal of the power supply is connected to an ground and connect a condenser for noise reoval between 0V and F.G. terinal. (Usually the condenser is equipped in switching ode power supply units) ode +V power supply 0V (SMPS) F.G Insulation transforer < Proper connections > Condenser for noise:0.001 to 0.1 μf /400V Frae High voltage line/ Power supply line Metallic pipe +V 0V In case of s aterial is etal, ground the etal case to prevent electrostatic or product alfunction due to noise High voltage line/ Power supply line Metallic pipe & Min. 30 Disturbing light Precaution for power supply Please do not operate the s ON/OFF by power. It is required at least 500s for stable operations after power supply is ON. A-95