Range Photoelectric Selection Sensors Guide Photoelectric Performance These charts were derived from the Excess Gain Curves for The selection of the proper photoelectric sensor for an each product. Excess Gain Curves for specific sensors are application is critical for reliable, trouble-free operation. The available on request from Namco Controls. graphs shown below are meant to be a guide for matching a type of environment to the sensor types most likely to perform If you have any questions regarding the suitability of a in that environment. Namco photoelectric sensor for your application, call our toll- free Technical Assistance Hotline at 1-800-NAMTECH (1-800- Fiber optic sensor types are not shown due to the different 626-8324). performance characteristics of the many styles of fiber optic cables. Suitable for use at these ranges in “clean” environments with no dirt, dust, or water accumulation on the lenses. Can be used at these ranges in slightly dirty environments; lenses should be cleaned regularly. Typical of warehouse or light industrial installations. At these ranges, the sensor can be used in moderately dirty applications where there is visible contamination of lenses or reflectors. Lenses should be cleaned regularly. Most industrial applications fit this category. Suitable for use in extremely dirty environments, or where heavy smoke, steam, or dust is present or when lenses will be cleaned only rarely. Typical environments are steel or paper mills. EP130 (1.0') EP130 (2.5') EP230 EP130 (6.5') EP210 EP110 EP220 EP120 .1 1 10 100 1000 Distance in feet NOTE: EP570 – See Excess Gain Chart in Photoelectric WFI Sensors section. Namco • 2013 West Meeting Street • Lancaster, SC 29720 • 1-803-286-8491 • FAX: 1-800-678-6263 132 Photoelectric Sensors General Photoelectric Information Sensors Evolution of Photoelectrics As photoelectrics have evolved, increasing emphasis has been placed on offering user-oriented values. Indicator lamps have been incorporated to signal sensing status; circuits have been expanded to include a solution for every wiring application; and with the implementation of surface mount technology, the features-to-size ratio has improved. Polarizing a light source orients the Sensor Light Sources Performance emitted rays into one plane. If a receiving The first photoelectrics used The performance of photoelectrics is photodiode is polarized in the same plane incandescent light sources. These early dependent on environmental conditions; as the received light, it will detect the products were susceptible to ambient e.g., air contamination, steam, fog, oil light. In sensing modes where retro- light conditions and limited in application. spray. Excess gain is merely a statement reflectors are used, the retro-reflector With the introduction of light emitting of how much extra gain the sensor has shifts the incident light 90 degrees. diodes (“L.E.D.’s”), the opportunity for over the minimum it needs to communi- Photoelectric sensors designed for this applying photoelectric sensors expanded. cate in ideal conditions at a given range. mode of sensing are polarized to expect a By modulating (pulsing) the L.E.D. and The higher the excess gain for a given shift of the incident light by the retro- tuning the receiving photodiode to distance, the more likely the photoelectric reflector. Any light returned by specular respond only to this rate of change, is to be able to penetrate through the reflection (from shiny objects) is not immunity to ambient light is improved. contamination to reach and be detected shifted and is intentionally undetected by Further enhancements have been by the corresponding receiving photo- the receiver. achieved by incorporating transmission diode. Since most applications are less filters to improve the signal-to-noise ratio than ideal, photoelectrics should be Photoelectric controls are applicable associated with ambient light. selected with ample excess gain for the in a wide range of industrial situations intended range. because of their long life, versatility, Reflectors are used in some sensing safety, and reliability. Namco’s sensors modes to provide an effective method for have been tested and proven over many returning the emitted light beam to the years of operation in all types of environ- receiving photodiode. While the most Output Options ments. Their precision optics can detect fundamental reflector returns the incident Most of the photoelectrics offered in objects that cannot be detected by light back to the source only when the this catalog are self-contained in that no conventional photoelectrics. Namco incident light strikes the reflector at 90 external stages of circuitry are required to photoelectric sensors are available in degrees to the surface of the reflector, the operate the sensors. Newer circuit types incandescent or LED and feature rugged more commonly used “corner cube” include 2-wire AC for ease of installation construction, long-life LED output retro-reflector will return the incident light and lowest cost installation, 3-wire AC for indication, and insensitivity to ambient to the receiving photodiode over a wide load current independent of input current, light. They also offer time delays, logic range of incident angles, making align- and 4-wire DC for user selectable sink delay systems, short circuit protection, ment angle with respect to the sensor (NPN) or source (PNP) connection. All of and reverse polarity protection. All significantly less critical. these are Programmable Logic Controller electronic circuitry is solid state. DC units compatible. may be operated from plant power supply or from optional relay/power pack combinations. 2013 West Meeting Street • Lancaster, SC 29720 1-803-286-8491 • FAX: 1-800-678-6263 www.namcocontrols.com For technical assistance, call 1-800-NAMTECH 133 Photoelectric Sensors Sensing Photoelectric Modes Sensors Retro- Reflective Sensing Mode Retro- reflective sensing is particularly effective in Thru-Beam Sensing Modes applications Thru-Beam (Opposed) that offer the Sensing Mode following conditions: (1) the object to be Thru-beam sensing should be beam is sensed by the receiver. As sensed is generally opaque; (2) a reflector employed wherever longer objects pass between the two can be easily installed so that the object sensing ranges (up to 400 units, the light beam is must pass between the reflector and the ft.) are required and where interrupted, and the corre- sensor; or (3) the object may be detected harsh or dirty environ- sponding sensor output is by adding reflective tape to the object. ments require more provided. Available ranges of retro units are powerful performance or Thru-beam is the most generally a fraction of the range of individually mounted reliable sensing mode. Since comparable size thru-beam units. transmitted receiver units. the receiver is a separate unit, In the retro-reflective mode, a single Thru-beam configura- sensing is totally immune to sensor is used to both send and receive tions consist of separate false proxing from shiny light directed to a reflector. Objects emitter and receiver units objects. Sensing of transpar- passing between the sensor unit and its aimed at one another and ent objects may require gain corresponding reflector interrupt the light separated so that objects control adjustment. Thru-beam systems beam and signal the sensor to provide the will pass between both units. Without the are inherently higher cost and require indicated output. Using corner cube presence of objects, the emitted light additional wiring to the second unit. reflectors enables the light signal to be returned to the sensor over a wide range of incident angles. Retro-reflective sensing is popular for its simplicity of installation, and if properly equipped with polarizing options, is independent of target material/color/ texture. Operates at distances of up to 30 feet. Retro-Reflective Sensing Modes Namco • 2013 West Meeting Street • Lancaster, SC 29720 • 1-803-286-8491 • FAX: 1-800-678-6263 134 Photoelectric Sensors Fiber-Optic Sensing Mode Diffuse Proximity Introducing a set of fiber-optic Glass cables have better light Sensing Mode cables to photoelectric sensors adds transmission capabilities, higher operat- Diffuse proximity sensing should be considerable flexibility from an applica- ing temperatures and cost, with a used when the following conditions exist: tions perspective. Fiber-optics work well sacrifice in physical flexibility. Glass (1) the object itself is sufficiently reflec- in applications requiring either small part cables cannot be cut to length by the tive to return incident light to the receiver detection or where space in average user. photodiode; the immediate vicinity of the Plastic cables are (2) the target object is at a premium. lower temperature rated, installation of Using fiber-optic cables to are less efficient in light a reflector on reach into environments too transmission, more the opposite harsh for the sensor unit flexible, lower cost, and side of the itself is a common applica- can be easily cut to length object is tion. Fiber-optic cables are in the field. impractical. immune to electrical and Protective jacketing for The radio frequency interference fiber-optics include either diffuse (EMI and RFI). stainless steel spiral wrap proximity The fiber-optic sensing armor or extruded pvc for mode utilizes mode is obtained simply by glass fibers and extruded a single adding fiber-optic cables to an existing pvc for plastic fibers. sensor unit as emitter and receiver and sensor designed to accommodate them. relies upon the object sighted to reflect Both glass and plastic fiber-optic While any sensing mode could utilize fiber- sufficient light to be sensed by the cables offer immunity to electrical optics, typical cable offerings are designed receiver. Absence of objects in the light interference and permit relocating of the for thru-beam and diffuse operation. Glass beam path result in light not returned to sensor unit in applications where the and plastic core materials are common in the receiver. environment in the sensing area is the industry, each offering their respec- unusually harsh. Diffuse sensing is the lowest cost tive advantages and tradeoffs. approach but depends on the reflectivity (and color) of the target material. This system is suitable for detecting like objects where the gain can be adjusted once for the best performance. Fiber Optic Sensing Modes 2013 West Meeting Street • Lancaster, SC 29720 1-803-286-8491 • FAX: 1-800-678-6263 www.namcocontrols.com For technical assistance, call 1-800-NAMTECH 135 Photoelectric Sensors Typical Photoelectric Wiring Sensors Diagrams Notes: 1. These diagrams are valid for sensors with cables and connectors. 2. Sensors may or may not have ground connections or grounded housings. Refer to the specific connector or cable diagram for your particular sensor’s model number to determine if it is grounded. 3. The markings on these wiring diagrams (L1, Load, etc.) are identical to those on the connector diagrams. 4. All switches are Normally Opened (N.O.) unless specifically marked Normally Closed (N.C.). 5. All switch outputs are Sourcing unless specifically marked Sink. AC Wiring Diagrams L1 L2 L1 LOAD 2-wire AC SENSOR LOAD GND L1 L2 3-wire AC SENSOR LOAD LOAD L1 L2 Namco • 2013 West Meeting Street • Lancaster, SC 29720 • 1-803-286-8491 • FAX: 1-800-678-6263 136 Photoelectric Sensors DC Wiring Diagrams -DC +DC -DC 3-wire DC +DC LOAD SENSOR LOAD Sourcing (PNP) +DC -DC 3-wire DC LOAD LOAD SENSOR Sinking (NPN) +DC -DC 4-wire DC SENSOR Sink (NPN)/ SINK SOURCE Source (PNP) LOAD LOAD +DC -DC 2013 West Meeting Street • Lancaster, SC 29720 1-803-286-8491 • FAX: 1-800-678-6263 www.namcocontrols.com For technical assistance, call 1-800-NAMTECH 137 Photoelectric Sensors