7B30 AD [Analog Devices], 7B30 Datasheet - Page 2

• Manufacturer Part Number: 7B30
• Description: Isolated, Voltage or Current Input
• Manufacturer: AD [Analog Devices]

GENERAL DESCRIPTION
The 7B30 is a single-channel signal conditioning module that
interfaces, amplifies and filters unipolar and bipolar milli-vilt
and voltage inputs and provides a protected precision output of
either +1 V to +5 V or 0V to +10 V.
To measure a process current input, a plug-in 250W 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 7B30
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 160 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 7B30 is nix-
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 7B30 is fully protected
Rev. 0 | Page 2 of 8
Figure 2
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 amplifier. Amplitude modulation is used to
implement transformer isolation (1500 V rms input-t-output
and power). Isolated front-end circuitry power is supplied by a
DC/DC converter. The output section contains a 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.
7B30