T18 Sensors ac-Voltage Series Self-contained ac-operated sensors Features Featuring EZ-BEAM technology, the specially-designed optics and electronics provide reliable sensing without the need for adjustments (most models) T style plastic housing with 18 mm threaded lens mount Models available in opposed, retroreflective, diffuse and fixed-field modes Completely epoxy-encapsulated to provide superior durability, even in harsh sensing environments to IP69K Innovative dual-indicator system takes the guesswork out of sensor performance monitoring 20 to 250V ac (3-wire hookup) SPST solid-state switch output, maximum load 300 mA Models Sensing Mode Range LED Output Model* T183E Opposed 20 m (66 ) LO T18AW3R Infrared DO T18RW3R 950 nm LO T18AW3L Retroreflective with Gain Control DO T18RW3L 2 m (79 ) LO T18AW3LP Polarized Visible Red P Retroreflective 680 nm DO T18RW3LP LO T18AW3D Diffuse 300 mm (12 ) with Gain Control DO T18RW3D LO T18AW3FF25 25 mm (1 ) cutoff DO T18RW3FF25 Infrared 880 nm LO T18AW3FF50 Fixed-Field 50 mm (2 ) cutoff DO T18RW3FF50 LO T18AW3FF100 100 mm (4 ) cutoff DO T18RW3FF100 * S tandard 2 m (6.5 ) cable models are listed. 9 m (30 ) cable: add suffix W/30 (e.g., T183E W/30). 4-pin Micro-style QD models: add suffix Q1 (e.g., T183EQ1). A model with a QD connector requires a mating cable. (See page 7.) Use polarized models when shiny objects will be sensed. WARNING . Not To Be Used for Personnel Protection Never use these products as sensing devices for personnel protection. Doing so could lead to serious injury or death. These sensors do NOT include the self-checking redundant circuitry necessary to allow their use in personnel safety applications. A sensor failure or malfunction can cause either an energized or de-energized sensor output condition. Consult your current Banner Safety Products catalog for safety products which meet OSHA, ANSI and IEC standards for personnel protection. Printed in USA 01/05 P/N 121525 T18 Sensors ac-Voltage Series Fixed-Field Mode Overview T18 Series self-contained fixed-field sensors are small, powerful, infrared diffuse mode sensors with far-limit cutoff (a type of background suppression). Their high excess gain and fixed-field technology allow them to detect objects of low reflectivity, while ignoring background surfaces. The cutoff distance is fixed. Backgrounds and background objects must always be placed beyond the cutoff distance. Cutoff Fixed-Field Sensing Theory of Operation Distance Object B The T18FF compares the reflections of its emitted light beam (E) from an object back to the Receiver Object or Elements A sensors two differently aimed detectors, R1 and R2 (see Figure 1). If the near detector (R1) Background Lenses Near light signal is stronger than the far detector (R2) light signal (see object A, closer than the R1 Detector cutoff distance), the sensor responds to the object. If the far detector (R2) light signal is Far stronger than the near detector (R1) light signal (see object B, beyond the cutoff distance), R2 Detector the sensor ignores the object. The cutoff distance for model T18FF sensors is fixed at 25, 50 or 100 millimeters (1 , 2 , or 4 ). Objects lying beyond the cutoff distance usually are ignored, even if they are highly Emitter E reflective. However, it is possible to falsely detect a background object, under certain conditions (see Background Reflectivity and Placement). Sensing Range In the drawings and discussion on these pages, the letters E, R1, and R2 identify how the sensors three optical elements (Emitter E, Near Detector R1, and Far Detector R2) Object is sensed if amount of light at R1 is greater than the amount of light at R2 line up across the face of the sensor. The location of these elements defines the sensing axis (see Figure 2). The sensing axis becomes important in certain situations, such as those Figure 1. Fixed-field concept illustrated in Figures 5 and 6. Sensor Setup Sensing Reliability For highest sensitivity, position the target object for sensing at or near the point of maximum excess gain. The excess gain curves for these products are shown on page 5. They show excess gain vs. sensing distance for sensors with 25 mm, 50 mm, and 100 mm (1 , 2 , and 4 ) cutoffs. Maximum excess gain for the 25 mm models occurs at a lens-to- Sensing Axis object distance of about 7 mm for 50 mm models, at about 10 mm and for the 100 mm models, at about 20 mm. Sensing at or near this distance will make maximum use of each sensors available sensing power. The background must be placed beyond the cutoff distance. (Note that the reflectivity of the background surface also may affect the cutoff distance.) Following these two guidelines will improve sensing reliability. Background Reefl ctivity and Placement Avoid mirror-like backgrounds that produce specular reflections. False sensor response will occur if a background surface reflects the sensors light more strongly to the near detector, or sensing detector (R1), than to the far detector, or cutoff detector (R2). The result As a general rule, the most reliable sensing of an object approaching from the is a false ON condition (Figure 3). To cure this problem, use a diffusely reflective (matte) side occurs when the line of approach is background, or angle either the sensor or the background (in any plane) so the background parallel to the sensing axis. does not reflect light back to the sensor (see Figure 4). Position the background as far beyond the cutoff distance as possible. Figure 2. Fixed-field sensing axis An object beyond the cutoff distance, either stationary (and when positioned as shown in Figure 5), or moving past the face of the sensor in a direction perpendicular to the sensing axis, can cause unwanted triggering of the sensor if more light is reflected to the near detector than to the far detector. The problem is easily remedied by rotating the sensor 90 (Figure 6). The object then reflects the R1 and R2 fields equally, resulting in no false triggering. A better solution, if possible, may be to reposition the object or the sensor. Banner Engineering Corp. Minneapolis, MN U.S.A. www.bannerengineering.com Tel: 763.544.3164 2 P/N 121525 R1 R2 E