isolated process control signal conditioning products scm7b for information call 800-444-7644 72 ?1995-2011 dataforth corporation, all rights reserved iso9001:2008-registered qms SCM7B32/33 isolated process current/v oltage input modules description the SCM7B32 current input modules accept input signals in the 4-20ma or 0-20ma ranges from the field and provide a high-level output to the process control system (figure 1). current to voltage conversion occurs internal to the module, which is factory calibrated to ensure the highest accuracy. scm7b33 voltage input modules accept input signals in the +1v to +5v or 0 to +5v ranges from the field and provide a high-level output to the process control system. as an alternative, the scm7b33 can be used with an external 250 ? resistor (dataforth scm7bxr1 or equivalent), to accept input signals in the 4-20ma or 0-20ma ranges. using the external sense resistor allows the module to be removed without disrupting the current loop. all scm7b33s are shipped with a scm7bxr1 resistor. these modules incorporate a five-pole filtering approach to maximize both time and frequency response by taking advantage of both thomson (bessel) and butterworth characteristics. one pole of the filter is on the field side of the isolation barrier; four are on the process control system side. after the initial field-side filtering (conversion-SCM7B32 only), the input signal is chopped by a proprietary chopper circuit and transferred across the trans- former isolation barrier, suppressing transmission of common mode spikes and surges. the signal is then reconstructed and filtered for process control system output. modules accept a wide 14 - 35vdc power supply range (+24vdc nominal). their compact packages (2.13"x1.705"x0.605" max) save space and are ideal for high channel density applications. they are designed for easy din rail mounting using any of the ?-din? backpanels. figure 1: SCM7B32/33 block diagram features accepts current or voltage input provides high-level voltage outputs 1500vrms transformer isolation accuracy, 0.03% of span typical, 0.1% max ansi/ieee c37.90.1 transient protection input protected to 120vrms continuous noise, 500vp-p (5mhz), 300vrms (100khz) 105db cmrr easy din rail mounting csa c/us certified ce and atex compliant http:///
scm7b visit our website www.dataforth.com 73 isolated process control signal conditioning products scm7b ?1995-2011 dataforth corporation, all rights reserved iso9001:2008-registered qms specifications typical at 25c and +24vdc module SCM7B32 scm7b33 input signal range 4-20ma, 0-20ma +1 to +5v, 0 to +5v bias current n/a 0.1na resistance normal <100 ? 2m ? power off <100 ? 2m ? overload 30k ? 2m ? protection continuous 120vrms max * transient ansi/ieee c37.90.1 * output signal range (1) ?? effective available power (1) 40mw * resistance < 1 ? * protection continuous short-to-ground * voltage/current limit 12v, 14ma * cmv (input-to-output) continuous 1500vrms * transient ansi/ieee c37.90.1 * cmrr (50 or 60hz) 105db * accuracy (2) 0.03% span typical, * 0.1% span max linearity (3) 0.01% span typical, * 0.02% span max stability (?40c to +85c) gain 35ppm/c * input offset n/a (4) * output offset 0.003% span/c * noise peak at 5mhz b/w 5 00v * rms at 10hz to 100khz b/w 3 00v * peak at 0.1hz to 10hz b/w 1v rti * frequency and time response bandwidth, ?3db 100hz * nmr (?3db at 100hz) 80db per decade above 100hz * step response, 90% span 5ms * supply voltage 14 to 35vdc * current (1) 12ma * sensitivity 0.0 001%/%v s * mechanical dimensions 2.13" x 1.705" x 0.605" max * (h)(w)(d) 54.1mm x 43.3mm x 15.4mm max * environmental operating temperature range ?40c to +85c * storage temperature range ?40c to +85c * relative humidity 0 to 95% noncondensing * emissions en61000-6-4 ism, group 1 * radiated, conducted class a * immunity en61000-6-2 ism, group 1 * rf performance a 0.5% span error * esd, eft performance b * notes: *specification same as preceding model (1) output range and supply current specifications are based on minimum output load resistance. minimum output load resistance is calculated by v out 2 /p e , where p e is the output effective available power that guarantees output range, accuracy, and linearity specifications. (2) accuracy includes the effects of repeatability, hysteresis, and linearity. (3) linearity is calculated using the best-fit straight line method. (4) input offset term included in output offset specification. ordering information model input range SCM7B32-01 4 to 20ma SCM7B32-02 0 to 20ma scm7b33-01 +1 to +5v scm7b33-02 0 to +5v output range part no. suffix example +1 to +5v none SCM7B32-01 0 to +5v a SCM7B32-01a 0 to +10v d SCM7B32-01d ? output ranges available http:///
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