7B35-01-2

Isolated Process Current Input with Loop Power 7B35 FEATURES FUNCTIONAL BLOCK DIAGRAM Single-channel signal conditioning current input module that interfaces with two-wire transmitters. Module provides a precision output of either +1 V to +5 V or +2 V to +10 V, linear with temperature. Features a isolated 24 VDC loop supply for driving the transmitter. All 7B35 series modules are mix-and-match and Hot Swappable. APPLICATIONS Industrial signal isolation Industrial signal filtering PRODUCT OVERVIEW The 7B Series of signal conditioners feature small size, low cost and a wide output voltage range for a variety of applications including process control and factory-floor environments. The single-channel 7B modules accept inputs from a range of transducers and are fully rated over the extended -40oC to +85oC industrial temperature range. All 7B Series modules are rated for a nominal power supply input of +24 VDC; and, for maximum flexibility, they will accept supply voltages in the +14 VDC to +35 VDC range. The input modules, with the exception of the 7B21, provide a high-level output voltage that is factory configured for either the +1 V to +5 V or 0 V to +10 V range. The 7B21 is a unity gain, isolated input module with an input/output range of +10V. Output modules are available that provide either isolated process current or isolated bipolar voltage output. Model 7B39 converts either a +1 V to +5 V input to a 4 to 20 mA output or a 0 V to +10 V input to a 0-20 mA output. The input/output ranges of the 7B39 are factory configured. The 7B22 is a unity gain module that provides an isolated +10V output signal. All modules have a universal pinout and may be readily hot-swapped under full power without disrupting field wiring. Each module accepts analog transducer signals and transfers them to a process control or factory data collection system without the inherent noise, non-linearity, drift and extraneous voltages which frequently accompany the signals. Figure 1. 7B35 Functional Block Diagram The modules feature a maximum nonlinearity of +0.02% and are factory calibrated to guarantee a maximum accuracy specification of +0.1%. The 7B Series offers up to 1500 V rms continuous common mode voltage isolation and 120 V rms of field wiring input protection. The power supplies necessary to drive each of the individual module’s input circuitry are internally isolated, enabling the 7B Series modules to offer true channel-to-channel isolation of the input signals. The modules directly accept analog signals from thermocouples, RTDs, current loop powered transmitters, and other process control signals. The 7B Series modules amplify, linearize, isolate, protect and convert the transducer output signals to standardized analog inputs for high-level analog I/O subsystems. The 7B Series Subsystem consists of 19-inch rackcompatible hardware (model AC 1363), with universal mounting backplane and a family of plug-in (up to 16 per backplane) input and output signal conditioning modules. Four, eight-, and sixteen-channel backplanes are available. Each backplane incorporates screw terminals for easy power connections and field wiring, and includes a 25-pin D-type connector for interfacing the high-level single-ended voltage outputs to the user’s equipment. Gold-plated sockets are provided on each channel of the backplane to ensure the reliability of each module’s electrical connection. 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 that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog.com Tel: 781.329.4700 Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved. 7B35 GENERAL DESCRIPTION isolated voltage provided by the 7B35 is between 13 VDC and 34 VDC for loop currents between 4 mA and 20 mA and supply voltages between 20.4 VDC and 26.4 VDC. The output section contains a two-pole low-pass filter (-3 dB @ 100 Hz), a buffer amplifier and power oscillator. The two-pole output filter and subsequent buffer ensures that a low noise, low impedance ( 2 kΩ) +1 V to +5 V or +2 V to +10 V Accuracy1 Initial @ +25°C 2 ±0.01% Span (±0.1% Span, maximum) Nonlinearity ±0.02% Span, maximum Input Offset vs. Temperature N/A3 Span vs. Temperature ±40 ppm/°C Output Offset vs. Temperature ±0.003% span/°C Output Noise 5 MHz Bandwidth 6 mV peak 10 Hz to 100 kHz Bandwidth 0.9 mV rms 0.1 Hz to 10 Hz Bandwidth 4 µV peak Bandwidth, -3 dB 100 Hz Output Rise Time, 10% to 90% Span 5 ms Common-Mode Voltage (CMV) Input-to-Output and Power 1500 V rms continuous Common Mode Rejection (CMR) Input-to-Output and Power @ 50/60 Hz 105 dB Input Protection 120 V rms, continuous ±35 V dc, continuous Input Transient Protection ANSI/IEEE C376.90.1-1989 IEEE-STD 472 IEC 255-4, Class II Rev. 0 | Page 3 of 8 7B35 Output Resistance