7B33_15 Datasheet, PDF (2/8 Pages) Analog Devices – Isolated, Voltage or Current Input

GENERAL DESCRIPTION
The 7B33 is a single-channel signal conditioning module that
interfaces, amplifies and filters unipolar voltage inputs and
provides a protected precision output of either +1 V to +5V or 0
V to +10 V. To measure a process current input, a plug-on 250Ω
current sensing resistor, Model AC1391, may be installed
directly on the 7B backplane, using available pin sockets. The
external current sense resistor allows the current loop to be
maintained even when the module is removed from the
backplane. Model 7B33 features a nonlinearity of +0.02%
maximum and an accuracy of +0.1% maximum (+0.01%
typical). To accurately measure low level signals in electrically
noisy environments, 1500 V rms of galvanic transformer-based
isolation with a common mode rejection (CMR) of 105 dB @
50/60 Hz is provided. Rated to operate with a nominal +24
VDC supply, Model 7B33 is mix-and-match and hot-swappable
with other 7B Series input modules, so it can be inserted or
removed from any socket in the same backplane without
disturbing system power.
The two input pins of Model 7B33 are fully protected up to 120
V rms line voltage. A one-pole 100 Hz filter preconditions the
input signal prior to amplification by a low drift input amplifier.
7B33
Amplitude modulation is used to implement transformer
isolation (1500 V rms input-to-output and power). Isolated
front-end circuitry power is supplied by a DC/DC converter.
The output section contains a two-pole low pass filter (-3 dB @
100 Hz), a buffer amplifier and a power oscillator. The two-pole
output filter and subsequent buffer ensures that a low noise, low
impedance (<1Ω) signal is available at the output to drive loads
of 2 kΩ minimum.
Figure 2
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