7B31

Rev. 0 | Page 2 of 8

GENERAL DESCRIPTION

The 7B31 is a single-channel signal conditioning module that

interfaces, amplifies and filters unipolar and bipolar voltage

inputs and provides a protected precision output of either +1 V

to +5 V or 0 V to +10 V. Model 7B31 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 120 dB @ 50/60 Hz and a normal mode rejection

(NMR) of 60 dB @ 50/60 Hz are provided. Rated to operate

with a nominal +24 VDC supply, Model 7B31 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 floating differential input of Model 7B31 is fully protected

up to 120 V rms line voltage. A one-pole 3 Hz filter

preconditions the input signal prior to amplification by a low

drift input (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 @

3 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