rev. 0 information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. a model 5b35 one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 world wide web site: http://www.analog.com fax: 781/326-8703 ? analog devices, inc., 1997 linearized 4-wire rtd input module functional block diagram general description model 5b35 converts the input from a wide variety of rtd types to a linearized, high accuracy output of 0 v to +5 v. the module provides transformer isolation, rtd excitation, rtd lead-resistance compensation, signal filtering and input protec- tion against line voltage connection. a series output switch eliminates the need for external multiplexing. the industry standard 5b series encapsulated plug-in modular package is compatible with all 5b backplanes. modules are powered by +5 v dc, 5%. signal isolation is provided by transformer coupling using a proprietary technique for linear, stable performance. a demodu- lator on the output side of the signal transformer recovers the input signal, which is filtered and buffered to provide an accu- rate, low impedance, low noise output. true three-port isolation includes common-mode voltage of: 1500 v rms between input and output, and between input and power; 250 v rms between output and power. the modules provide rtd excitation from a precision current source. a low drift, chopper stabilized, differential amplifier design allows for the use of very low rtd excitation currents to minimize accuracy losses from self-heating of the rtd. the low input offset drift of 0.01 c/ c and gain drift of 30 ppm/ c assure that accuracy is maintained over a wide operating tem- perature range. features accepts a variety of rtd types 100 v platinum, 10 v copper, 120 v nickel linearizes rtd signal 1500 v rms input/output and input/power isolation 250 v rms output/power isolation 240 v rms field wiring protection 4-wire lead resistance compensation 190 db cmrr 116 db nmr @ 60 hz, 108 db @ 50 hz low drift: input offset 6 0.01 8 c/ 8 c gain 6 30 ppm/ 8 c low output noise: 0.3 mv p-p @ 100 khz bw 6 mv p-p @ 5 mhz bw low power consumption: +5 v dc @ 15 ma ansi/ieee c37.90.1C1989 transient protection csa, fm and ce approvals the four-wire configuration of the 5b35 supplies the rtd excitation current through two leads that are not the signal input leads. because there is no excitation current in the signal input leads, the lead lengths or resistances have no effect on the rtd measurement. an optimized five-pole butterworth filter (with 4 hz bandwidth) provides 116 db of normal-mode rejection at 60 hz and 108 db at 50 hz. output noise is an exceptionally low 0.3 mv p-p at 100 khz bandwidth and 6 mv p-p at 5 mhz bandwidth. the input circuit is protected against accidental application of voltages, such as an ac power line, up to 240 v rms continuous. a series output switch is included to eliminate the need for external multiplexing in many applications. this switch has a low output resistance and is controlled by an active-low enable input. when the output switch is not used, ground the enable input to i/o common to turn on the switch. signal isolation chopper dif amp 4-pole active lpf p.s. power isolation rect. and filter power osc. v out i/o com read en (0) +5v pwr com 4 3 2 1 prot 4-wire rtd 5b backplane 5b35 nc nc nc = no connect prot. & filter
C2C rev. 0 model 5b35Cspecifications c3194C2C10/97 printed in u.s.a. model 5b35 input standard ranges see table i custom range limits (see table ii for more information) 100 w pt C200 c to +850 c 120 w ni C80 c to +320 c 10 w cu C100 c to +260 c impedance normal (power on) >1000 m w power off 200 k w overload 200 k w normal-mode rejection (nmr) 116 db (60 hz); 108 db (50 hz) protection continuous 240 v rms max transient ansi/ieee c37.90.1-1989 sensor excitation current 100 w pt, 120 w ni 0.25 ma 10 w cu 1.0 ma lead resistance effect 100 w pt, 120 w ni 0.00001 c/ w 10 w cu 0.0001 c/ w common-mode voltage (cmv) input-to-output, continuous 1500 v rms, max input-to-power, continuous 1500 v rms, max power-to-output, continuous 1 250 v rms, max common-mode rejection (cmr), 50/60 hz 2 190 db accuracy initial @ +25 c 3 see table i conformity error 0.05% span stability vs. temperature (C40 c to +85 c) input offset 0.01 c/ c output offset 20 m v/ c gain 30 ppm of reading/ c output range 0 v to +5 v resistance 25 w bandwidth 4 hz step response time (10% to 90% range) 100 ms noise input, 0.1 hz to 10 hz 0.2 m v rms output, 100 khz bandwidth 100 m v rms 0.3 mv p-p output, 1 mhz bandwidth 1.5 mv p-p output, 5 mhz bandwidth 6 mv p-p protection continuous short to ground current limit 9 ma enable time (c load = 0 pf to 2000 pf) 6 m s to 1 mv of v out enable control max logic 0 +0.8 v min logic 1 +2.4 v max logic 1 +100 v input current 0, 1 0.5 m a power supply voltage, rated performance +5 v dc 5% current 15 ma sensitivity (100 w pt, 120 w ni, 10 w cu) 0.2 c/v case size, maximum 2.275" 2.325" 0.595" (57.8 mm 59.1 mm 15.1 mm) weight 70 grams environmental temperature range, rated performance C40 c to +85 c storage temperature C40 c to +85 c relative humidity 0% to 93% @ +40 c, noncondensing rfi susceptibility 0.5% span error @ 400 mhz, 5 w, 3' notes 1 the users board layout must separate power ground from i/o common and when the 5b35 output switch is not used, ground the ena ble input to i/o common. power-to-output cmv is not available when the 5b35 is installed on a 5 b series backplane. 2 cmr for model 5b35-04 is 180 db. 3 includes the combined effects of repeatability, hysteresis and conformity. specifications subject to change without notice. (typical @ +25 8 c and v s = +5 v dc) table i. standard model input/output ranges* model input range accuracy 100 w platinum, a = 0.00385* 5b35-01 C100 c to +100 c 0.26 c (C148 f to +212 f) 5b35-02 0 c to +100 c 0.13 c (+32 f to +212 f) 5b35-03 0 c to +200 c 0.26 c (+32 f to +392 f) 5b35-04 0 c to +600 c 0.78 c (+32 f to +1112 f) 5b35-05 C100 c to +200 c 0.60 c (C148 f to +392 f) 10 w copper, a = 0.004274 5b35-c-01 0 c to +120 c 0.23 c (10 w at 0 c) (+32 f to +248 f) 5b35-c-02 0 c to +120 c 0.23 c (10 w at +25 c) (+32 f to +248 f) 120 w nickel, a = 0.00672 5b35-n-01 0 c to +300 c 0.40 c (+32 f to +572 f) *standard output range for all models is 0 v to +5 v. custom input/output ranges are available, including versions for the 100 w platinum ( a = 0.003916) rtd. see table ii. table ii. custom model ordering guide order model: 5b35-custom* plus customer specified information customer specified information: sensor type input range output range available low high low high sensor types limit limit limit limit 100 w pt a = 0.00385 C200 c +850 c 0 v +5 v 100 w pt a = 0.003916 C200 c +850 c 0 v +5 v 10 w cu a = 0.004274 consult factory 0 v +5 v 120 w ni a = 0.00672 consult factory 0 v +5 v *for copper (cu) rtd sensor inputs, order 5b35-c-custom. for nickel (ni) rtd sensor inputs, order 5b35-n-custom .
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