agilent heds-9710, HEDS-9711 200 lpi analog output small optical encoder modules data sheet description the heds-9710/HEDS-9711 series is a high performance, low cost, optical incremental encoder mod- ule. when operated in conjunction with either a codewheel or codestrip, this module detects ro- tary or linear position. the encoder 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 tol- erant to mounting misalignment. the two-channel analog outputs and 5 v supply input are accessed through four solder-plated leads located on 2.54 mm (0.1 inch) centers. the standard heds-9710/heds- 9711 is designed for use with an features ? small size ? multiple mounting options ? 200 lpi resolution ? linear and rotary options available ? insensitive to radial and axial play ?15 c to 45 c operating temperature ? two-channel analog output ? single 5 v supply ? wave solderable esd warning: normal precautions should be taken to avoid static discharge. appropriate optical radius codewheel, or linear codestrip. please contact the factory for more information. applications the heds-9710/HEDS-9711 provides sophisticated motion detection at a low cost, making closed-loop control very cost- effective. typical applications include printers, plotters, copiers, and office automation equipment. 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. theory of operation the heds-9710/HEDS-9711 is a c-shaped emitter/detector mod- ule. coupled with a codewheel, it translates rotary motion into a two-channel analog output. coupled with a codestrip, it trans- lates linear motion into analog outputs.
2 the module contains a single light emitting diode (led) as its light source. the light is colli- mated into a parallel beam by means of a single lens located directly over the led. opposite the emitter is the integrated de- tector circuit. this ic consists of multiple sets of photodetectors and the signal processing cir- cuitry necessary to produce the analog waveforms. the codewheel/codestrip moves between the emitter and detector, causing the light beam to be in- terrupted by the pattern of spaces and bars on the codewheel/ codestrip. the photodiodes which detect these interruptions are arranged in a pattern that corre- sponds to the radius 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, which produces the final outputs for channels a and b. due to this integrated phasing technique, the analog output of channel a is in quadrature with channel b (90 degrees out of phase). package dimensions see heds-9700 datasheet for package outline drawings. definitions count (n) : the number of bar and window pairs or counts per revolution (cpr) of the code- wheel, or the number of lines per inch (lpi) of the codestrip. 1 shaft rotation = 360 mechanical degrees = n cycles 1 cycle (c) = 360 electrical degrees ( e) = 1 bar and window pair pulse width (p) : the number of electrical degrees that an output is high during one cycle. this value is nominally 180 e or 1/2 cycle. pulse width error ( d 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 four states per cycle, each nominally 90 e. state width error ( d s) : the deviation, in electrical degrees, of each state width from its ideal value of 90 e. phase ( f ) : the number of elec- trical degrees between the center of the high state of channel a and the center of the high state of channel b. this value is nomi- nally 90 e for quadrature output. phase error ( df ) : the devia- tion of the phase from its ideal value of 90 e. direction of rotation : when the codewheel rotates counter- clockwise, as viewed looking down on the module (so the marking is visible), channel a will lead channel b. if the codewheel rotates in the opposite direction, channel b will lead channel a. optical radius (r op ) : the distance from the codewheels center of rotation to the optical center (o.c.) of the encoder module. mounting position (r m ) : distance from motor shaft center of rotation to center of alignment tab receiving hole. absolute maximum ratings parameter symbol min. max. units notes storage temperature t s C40 85 c operating temperature t a 15 45 c supply voltage v cc C0.5 7 v soldering temperature 260 ct 5 sec. recommended operating conditions parameter symbol min. max. units notes temperature t 15 45 supply voltage v cc 4.8 5.2 v ripple < 100 mv p-p count frequency 8 khz (velocity (rpm) x n) 60
3 waveform definition iap ibp ibm iam a b a b analog digital p p s1 s2 s3 s4 name paramenter definition label analog peak the absolute value in m a of the magnitude of the iap, ibp, analog signal (i.e., one-sided reading). iam, ibm analog peak-to-peak ipp the peak-to-peak signal magnitude in m a of the iapp analog signal. ibpp analog offset ioffset the offset in m a from the mid-point of the analog peak-to-peak signal to the zero current point. state width state width the number of electrical degrees between a transition state 1 in channel a and the neighboring transition in channel b. state 2 there are four states per cycle, each nominally 90 e. state 3 the transitions are determined by where the analog state 4 signal crosses the zero point. state width error state width error the deviation, in electrical degrees, of each state width from its ideal value of 90 e. pulse width pulse width the number of electrical degrees that an analog output p is greater than zero during one cycle. this value is nominally 180 e or 1/2 cycle. pulse width error pulse width error the deviation, in electrical degrees, of each pulse width from its ideal value of 180 e. electrical characteristics electrical characteristics over recommended operating range, typical at 25 c. parameter symbol min. typ. max. units notes supply current i cc 17 40 ma
4 encoding characteristics encoding characteristics over recommended operating range and recommended mounting tolerances. these characteristics do not include codewheel/codestrip contributions. units radial microns 130 tangential microns 130 gap microns 50 C 250 temperature c 15 C 45 o.r. mm 18 C linear cpr count 900 C linear codewheel slot/spoke ratio 0.9 C 1.1 min. max. ipp m a1073 ioffset m aC4+4 state width error e C40 +40 pulse width error e C40 +40 recommended codewheel and codestrip characteristics parameter symbol min. max. units notes window/bar ratio ww/wb 0.9 1.1 window length (rotary) lw 1.80 2.30 mm (0.071) (0.091) (inch) absolute maximum codewheel rc rop + 3.40 mm includes eccenC radius (rotary) (rop + 0.134) (inch) tricity errors center of post to inside w1 1.04 mm edge of window (0.041) (inch) center of post to outside w2 0.76 mm edge of window (0.030) (inch) center of post to inside edge l 3.60 mm of codestrip (0.142) (inch)
5 analog encoder interface circuit i a-in v ref i+ + c r1 v a i b-in v ref i+ + c r1 v b v ref = 1.4 v ?0.2 v (dc) the circuit shown can be used to convert the current output to a voltage. resistor value, r1, and capacitor, c, are specified to attain required gain and low-pass filtering, which are application specific. the gain is chosen to attain maximum output swing and not clamp the op-amp. v ref should be set to 1.4 v 0.2 v. a 0.1 m f bypass capacitor (decoupling capacitor) is recom- mended to be placed within 1 cm of the encoder for optimal power supply noise rejection. outputs are high impedance (typical 1 m ohm) and susceptible to emi. ordering information heds-971 lead configurations 0 C straight leads 1 C bent leads resolutions r C 200 lpi option bracket options 50 51
package dimensions option 50 package dimensions option 51 xxxxx yyww c x 50 agilent 8.7 6.4 0.14
(optical center) 2x ? 2.00 ?0.02 1.4 5.0 3.9 r 1.4 10.1 7.5 4.2 3.90 ?0.10 0.8 1.70 ?0.15 4.2 3.0 9.8 1.8 3.8 0.5 20.2 ?0.5 15.0 8.4 part #
(refer -05) c = country
of origin
marking
(refer -05
for details)
date code 12.6 ?0.5 7.0 option code pin 1 id ch b v cc ch a gnd lead thickness = 0.25 mm
lead pitch = 2.54 mm 10.8 ?0.5 5.5 ?0.3 r 2.6 xxxxx yyww c x 51 agilent 8.7 6.4 0.14
(optical center) 2x ? 2.00 ?0.02 4.34 ?0.20 3.9 10.1 7.5 4.2 3.90 ?0.10 0.8 1.70 ?0.15 4.2 3.0 9.8 1.8 3.8 0.5 20.2 ?0.5 15.0 8.4 part #
(refer -05) date code 12.6 ?0.5 7.0 option code pin 1 id ch b v cc ch a gnd lead thickness = 0.25 mm
lead pitch = 2.54 mm 10.8 ?0.5 5.5 ?0.3 ? 2.8 c = country
of origin
marking
(refer -05
for details)
package dimensions bent version C option 50 package dimensions bent version C option 51 xxxxx yyww c x 50 agilent 8.7 6.4 0.14
(optical center) 2x ? 2.00 ?0.02 r 2.6 1.4 5.0 3.9 r 1.4 10.1 7.5 4.2 3.90 ?0.10 0.8 1.70 ?0.15 9.2 ?0.3 5?typ. 4.2 3.0 ?0.3 6.0 9.8 1.8 10.8 ?0.5 3.8 0.5 20.2 ?0.5 15.0 8.4 part #
(refer -05) date code 12.6 ?0.5 7.0 option code pin 1 id ch b v cc ch a gnd lead thickness = 0.25 mm
lead pitch = 2.54 mm c = country
of origin
marking
(refer -05
for details)
xxxxx yyww c x 51 agilent 8.7 6.4 0.14
(optical center) 2x ? 2.00 ?0.02 4.34 ?0.20 3.9 ? 2.8 10.1 7.5 4.2 3.90 ?0.10 0.8 1.70 ?0.15 9.2 ?0.3 5?typ. 4.2 3.0 ?0.3 6.0 9.8 1.8 10.8 ?0.5 3.8 0.5 20.2 ?0.5 15.0 8.4 part #
(refer -05) date code 12.6 ?0.5 7.0 option code pin 1 id ch b v cc ch a gnd lead thickness = 0.25 mm
lead pitch = 2.54 mm c = country
of origin
marking
(refer -05
for details)
www.agilent.com/semiconductors for product information and a complete list of distributors, please go to our web site. for technical assistance call: americas/canada: +1 (800) 235-0312 or (408) 654-8675 europe: +49 (0) 6441 92460 china: 10800 650 0017 hong kong: (+65) 6271 2451 india, australia, new zealand: (+65) 6271 2394 japan: (+81 3) 3335-8152(domestic/interna- tional), or 0120-61-1280(domestic only) korea: (+65) 6271 2194 malaysia, singapore: (+65) 6271 2054 taiwan: (+65) 6271 2654 data subject to change. copyright ? 2002 agilent technologies, inc. obsoletes 5988-3614en may 10, 2002 5988-6261en note: these dimensions include shaft end play and codewheel warp. all dimensions for mounting the module and codewheel/codestrip should be measured with respect to the two mounting posts, shown above. mounting tolerances case 1 specifies the mounting tolerances required on rm in order to achieve the respective encoding characteristics shown on page 4. the mounting tolerances are as follows: case 1: rm 0.13 mm (.005 inches) recommended screw size: m2.5 x 0.45 or 2-56 mounting considerations
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