AEDT-9140-F00

AEDT-9140 Series High Temperature 115qC Three Channel Optical Incremental Encoder Modules 100 CPR to 1000 CPR Data Sheet Description Features The AEDT-9140 series are three channel optical incremental encoder modules. When used with a codewheel, these low cost modules detect rotary position. Each module consists of a lensed LED source and a detector IC enclosed in a small plastic package. Due to a highly collimated light source and a unique photodetector array, these modules are extremely tolerant to mounting misalignment. x Two channel quadrature output with index pulse The AEDT-9140 has two channel quadrature outputs plus a third channel index output. This index output is a 90 electrical degree high true index pulse which is generated once for each full rotation of the codewheel. x Small size The AEDT-9140 optical encoder is designed for use with a codewheel which has an optical radius of 11.00 mm (0.433 inch) for 100 CPR to 1000 CPR and 11.68 mm (0.460 inch) for 1000 CPR. The quadrature signals and the index pulse are accessed through five 0.46 mm square pins located on 1.27 mm (pitch) centers. x Resolution from 100 CPR to 1000 CPR (Cycles Per Revolution) x Low cost x Easy to mount x No signal adjustment required x -40qC to 115qC operating temperature x TTL compatible x Single 5V supply Applications Typical applications include: x Printers x Plotters x Tape drives x Machine tools x Industrial and factory automation equipment. Note: Avago Technologies encoders are not recommended for use in safety critical applications. Eg. ABS braking systems, power steering, life support systems and critical care medical. Theory of Operation Definitions The AEDT-9140 is an emitter/detector module. Coupled with a codewheel, these modules translates rotary motion of a shaft into a three-channel digital output. Note: Refer to Figure 2 As seen in Figure 1, the modules contain a single Light Emitting Diode (LED) as its light source. The light is collimated into a parallel beam by means of a single polycarbonate lens located directly over the LED. Opposite the emitter is the integrated detector circuit. This IC consists of multiple sets of photodetectors and the signal processing circuitry necessary to produce the digital waveforms. The codewheel rotates between the emitter and detector, causing the light beam to be interrupted by the pattern of spaces and bars on the codewheel. The photodiodes which detect these interruptions are arranged in a pattern that corresponds to the radius and design of the code-wheel. These detectors are also spaced such that a light period on one pair of detectors corresponds to a dark period on the adjacent pair of detectors. The photodiode outputs are then fed through the signal processing circuitry resulting in A, A-bar, B, B-bar, I and Ibar. Comparators receive these signals and produce the final output for channels A and B. Due to this integrated phasing technique, the digital output of channel A is in quadrature with that of channel B (90 degrees out of phase). Cycles (N): The number of electrical cycles per revolution (CPR). Note: CPR refers to the raw signal from encoder, that is the cycles before 4x decode. One Cycle (C): 360 electrical degrees (qe). One Shaft Rotation: 360 mechanical degrees, N cycles. Cycle Error ('C): An indication of cycle uniformity. The difference between an observed shaft angle which gives rise to one electrical cycle, and the nominal angular increment of 1/N of a revolution. Pulse Width (S): The number of electrical degrees that an output is high during 1 cycle. This value is nominally 180°e or 1/2 cycle. Pulse Width Error ('P): The deviation, in electrical degrees, of the pulse width from its ideal value of 180°e. State Width (S): The number of electrical degrees between a transition in the output of channel A and the neighboring transition in the output of channel B. There are 4 states per cycle, each nominally 90°e. State Width Error ('S): The deviation, in electrical degrees, of each state width from its ideal value of 90°e. Phase Error ('I): The deviation of the phase from its ideal value of 90°e. Direction of Rotation: When the codewheel rotates in the clockwise direction viewing from top of the module (direction from V to G), channel A will lead channel B. If the codewheel rotates in the opposite direction, channel B will lead channel A. Optical Radius (Rop): The distance from the codewheel’s center of rotation to the optical center (O.C) of the encoder module. Index Pulse Width (Po): The number of electrical degrees that an index is high during one full shaft rotation. This value is nominally 90qe or 1/4 cycle. 2 Block Diagram VCC RESISTOR LENS PHOTO DIODES COMPARATORS A A CH. A B B CH. B LED CH. I I I INDEX PROCESSING CIRCUITRY SIGNAL PROCESSING CIRCUITRY EMITTER SECTION Figure 1. Output Waveforms Figure 2. 3 CODE WHEEL DETECTOR SECTION GND AEDT-9140 Technical Specifications Absolute Maximum Ratings Parameter Symbol Min. Max. Units Storage Temperature TS -40 115 °C Operating Temperature TA -40 115 °C Supply Voltage VCC -0.5 7 Volts Output Voltage VO -0.5 VCC Volts Output Current per Channel, Iout IOUT -1.0 18 mA Notes Recommended Operating Conditions Parameter Symbol Min. Temperature TA -40 Supply Voltage VCC 4.5 Load Capacitance Frequency Typ. Max. Units 115 °C 5.5 Volts Ripple < 100mVp-p CL 100 pF 2.7 kΩ pull-up f 100 kHz Velocity (rpm) x N/60 Shaft Perpendicularity Plus Axial Play r 0.20 (r 0.008) mm (in.) Refer to Mounting Consideration Shaft Eccentricity Plus Radial Play 0.04 (0.0015) mm (in.) Refer to Mounting Consideration 5.0 Notes Electrical Characteristics Electrical characteristics over recommend operating range, typical at 25qC. Parameter Symbol Min. Typ Max. Units Supply Current ICC 30 57 85 mA High Level Output Voltage VOH 2.4 Low Level Output Voltage VOL Rise Time tr Fall Time tf Note: Typical values specified at Vcc = 5.0 V and 25 °C 4 Notes V Typ. IOH = -0.5 mA V Typ. IOL = 10 mA 180 ns 50 ns CL = 25 pF RL = 2.7 k: pull-up 0.4 Encoding Characteristics AEDT-9140 (except – B0B) Encoding Characteristics over the recommended operating conditions and recommended mounting tolerances unless otherwise specified. Parameter Symbol Cycle Error Min. Typ. Max. Units ∆C 3 15 °e Pulse Width Error ∆P 7 30 °e Logic State Width Error ∆S 5 30 °e Phase Error ∆φ 2 15 °e Position Error ∆Θ 10 40 min. of arc Index Pulse Width Po 60 90 120 °e CH I rise after CH B or CH A fall -40°C to + 115°C t1 10 100 1000 ns CH I rise after CH A or CH B rise -40°C to + 115°C t2 10 300 1000 ns Encoding Characteristics AEDT-9140-B0B & AEDT-9140-B00 Encoding characteristics over the recommended operating conditions and recommended mounting tolerances unless otherwise specified. Parameter Typ. Max. Units ∆C 3 6 15 20 °e Pulse Width Error ∆P 7 50 °e Logic State Width Error ∆S 5 50 °e Phase Error ∆φ 2 15 °e Position Error ∆Θ 10 40 min. of arc Index Pulse Width Po 40 90 120 °e -40°C to + 115°C t1 10 450 1500 ns CH I rise after -40°C to + 115°C CH A or CH B rise t2 10 250 1500 ns Cycle Error Symbol - B0B option - B00 option CH I rise after CH B or CH A fall 5 Min. Electrical Interface To ensure reliable encoding performance, the AEDT-9140 three channel encoder modules require 2.7 kΩ (± 10%) pull-up resistors on output pins 2, 3, and 5 (Channels A, I and B) as shown in Figure 3. These pull-up resistors should be located as close to the encoder module as possible (within 4 feet). Each of the three encoder module outputs can drive a single TTL load in this configuration. Figure 3. Customized Solutions CPR calculation formula: Customization of codewheel CPR is possible. It has to be based on the encoder LPI table given below. CPR = LPI x 2 x S x ROP 25.4 Part Number LPI Where: AEDT-9140-C00 36.7 CPR = Counts Per Revolution AEDT-9140-E00 73.5 LPI = Encoder LPI provided in the table AEDT-9140-F00 94 ROP = Encoder Optical Radius in mm AEDT-9140-G00 132.3 AEDT-9140-H00 147 * Recommended maximum codewheel diameter should not exceed 30mm. AEDT-9140-A00 183 AEDT-9140-I00 188 AEDT-9140-B0B 346 AEDT-9140-B00 367.5 6 Note: The customization of the codewheel method is valid from theoretical standpoint. However Avago strongly recommends a full characterization to be done to determine the actual performance of the encoder with customized codewheel. Characterization means validating the encoding performance (consist of cycle error, pulse width error, logic state width error, phase error, position error & index pulse width, index channel rise and fall time over the recommended operating conditions and recommended mounting tolerances. Mounting Considerations SHAFT CENTER AXIS OPTICAL CENTER AXIS ARTWORK GAP TYPICAL 0.50 EG R0.89 Codewheel MOUNTING PLANE Rop MOUNTING BOSS 2MM DIA. 2 PLACES 6.30 ET OPTICAL CENTER AXIS 12.60 Recommended Screw Size: M1.6 x 0.35 Recommended Mounting Screw Torque : 1 Lbin (0.113 Nm) ER Note: These dimensions include shaft endplay and codewheel warp. All dimension for mounting the module and codewheel should be measured with respect to two mounting boss, as shown above. Error Rop = 11mm Unit Notes EG Gap ± 0.20 mm Recommend to mount the codewheel closer to the detector side (upper side) for optimum encoder performance. ER Radial ± 0.13 mm ET Tangential ± 0.13 mm 7 Package Dimension Optical Center Axis 17.80 21.60 R15.50 3.00 1.60 4.40 Optical Center Axis 2.69 3.69 Top View 5.34 1.17 Optical Center Axis 13.60 1.27 0.46 3.69 3.00 2.40 13.6 Front View 1.78 4.00 4.90 R0.89 0.80 1.6 Side View 2.00 21.60 TYPICAL DIMENSIONS IN MILLIMETERS 8 Ordering Information AEDT-9140 Option Resolution Options C E F G H A I B - 100 CPR 200 CPR 256 CPR 360 CPR 400 CPR 500 CPR 512 CPR 1000 CPR Codewheels Optical Radius 00 - 11.00 mm 0B - 11.68 mm For product information and a complete list of distributors, please go to our web site: www.avagotech.com Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries. Data subject to change. Copyright © 2005-2009 Avago Technologies. All rights reserved. AV02-1101EN - November 10, 2009