Electronica

Small Optical Encoder Modules Technical Data

HEDS-9700 Series

Features
• Small Size • Low Cost • Multiple Mounting Options • Wide Resolution Range • Linear and Rotary Options Available • No Signal Adjustment Required • Insensitive to Radial and Axial Play • -40°C to +85°C Operating Temperature

• Two Channel Quadrature Output • TTL Compatible • Single 5V Supply • Wave SolderableDescription
The HEDS-9700 series is a high performance, low cost, optical incremental encoder module. When operated in conjunction with either a codewheel or codestrip, this module detects rotary or linear position. The

Package Dimensions

A

Mounting Option #50 - Standard (Baseplane Mounting)

Contact Factory for Detailed Package Dimensions

ESD WARNING; NORMAL HANDLING PRECAUTIONS SHOULDBE TAKEN TO AVOID STATIC DISCHARGE.

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module consists of a lensed LED source and a detector IC enclosed in a small C-shaped plastic package. Due to a highly collimated light source and a unique photodetector array, the module is extremely tolerant to mounting misalignment. The two channel digital outputs and 5V supply input are accessed through four solder-plated leads located on 2.54 mm(0.1 inch) centers. The standard HEDS-9700 is designed for use with an 11 mm optical radius codewheel, or linear codestrip. Other options are available. Please contact factory for more information.

Note: Agilent Technologies encoders are not recommended for use in safety critical applications. Eg. ABS braking systems, power steering, life support systems and critical care medical equipment.Please contact sales representative if more clarification is needed.

processing circuitry necessary to produce the digital waveforms. The codewheel/codestrip moves between the emitter and detector, causing the light beam to be interrupted by the pattern of spaces and bars on the codewheel/codestrip. The photodiodes which detect these interruptions are arranged in a pattern that corresponds to theradius and count density of the codewheel/ codestrip. 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 fed through the signal processing circuitry. Two comparators receive these signals and produce the final outputs for channels A and B. Due to this integrated phasingtechnique, the digital output of channel A is in quadrature with channel B (90 degrees out of phase).

Theory of Operation
The HEDS-9700 is a C-shaped emitter/detector module. Coupled with a codewheel, it translates rotary motion into a two-channel digital output. Coupled with a codestrip, it translates linear motion into a digital output. As seen in the block diagram, the module contains a single LightEmitting Diode (LED) as its light source. The light is collimated into a parallel beam by means of a single 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

Applications
The HEDS-9700 provides sophisticated motion detection at a low cost, making closed-loop control verycost-competitive! Typical applications include printers, plotters, copiers, and office automation equipment.

Block Diagram

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Output Waveforms

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 (φ): The number ofelectrical degrees between the center of the high state of channel A and the center of the high state of channel B. This value is nominally 90°e for quadrature output. Phase Error (∆φ): The deviation of the phase from its ideal value of 90°e. Direction of Rotation: When the codewheel rotates counterclockwise, as viewed looking down on the module (so the marking is visible), channel A will lead channel B....