3B40/3B41 Isolated Wideband Voltage Input


Models 3B40 and 3B41The 3B40 and 3B41 are wide-bandwidth (10 kHz) single-channel signal conditioning modules which amplify, isolate, filter and protect analog input voltages and provide simultaneous precision voltage and current outputs. Each module performs complete signal conditioning, including isolating (±1500 V peak input-to-output and power) and protecting their computer side outputs from damage and loss of signal integrity, and shielding their inputs from damage from field-side overvoltage faults up to 220 V rms. The current output withstands 130 V rms without damage and interfaces user equipment through screw terminals located on the 3B Series backplane. Each plug-in, mix-and-match, hot-swappable module is easily field calibrated via front-panel zero and span adjustments for both voltage and current outputs.

3B Series Custom-Ranging Program

Externally-programmable versions, Models 3B40-00 and 3B41-00, enable the user to configure a special input range by using the optional plug-on AC1310 ranging card, which houses user-supplied resistors to determine zero and span. To facilitate selecting resistors, a Windows® program, 3B-CUSTOM, calculates resistor values based on the user-desired input/output ranges.

Inside the 3B40 and 3B41 Module

A chopper-stabilized low-drift (±1µV/°C) input amplifier assures stable long-term stability. At the amplifier input, a stable, zero-scale input voltage is subtracted from the input signal to set the zero-scale value. Zero suppression can exceed 100% of the input range. This is ideal for expanded-scale applications requiring high-resolution measurement of a selected portion of an input signal. For user convenience, the zero and span can be factory configured to meet custom range needs (Models 3B40-CUSTOM and 3B41-CUSTOM) or can be externally programmed (Models 3B40-00 and 3B41-00) via user supplied resistors inserted in the optional AC1310 plug-on ranging card. Internal filtering with a 10 kHz cutoff (-3dB) is determined by a two-pole Butterworth filter.

Signal isolation is accomplished by transformer coupling with a proprietary modulation technique for linear, stable and reliable performance. The differential input circuit on the field side is fully floating, eliminating the need for any input grounding. A demodulator on the computer side of the signal transformer recovers the original signal, which is then filtered and buffered to provide a low-noise, low-impedance output voltage; this output also drives a voltage-to-current (V/I) converter to provide a simultaneous current output for interfacing versatility.

Input and Output Ranges

3B40/3B41 Functional Block Diagram

Figure 1. 3B40/3B41 Functional Block Diagram

3B40 Input Field Connections
3B41 Input Field Connections
Figure 2. 3B40 Input Field Connections
Figure 3. 3B41 Input Field Connections

Input Type
Dual Outputs
3B40: ±10 mV to ±1 V
-10 V to +10 V or 0 to +10 V
3B41: ±1 V to ±10 V
0 to 20 mA or 4 mA to 20 mA

3B40 and 3B41 Models Available

Model  Input Range Output Ranges1
Order Now 3B40-00
-10 V to +10 V & 0 mA to 20 mA
Order Now
-10 mV to +10 mV
-10 V to +10 V & 0 mA to 20 mA
Order Now
-50 mV to +50 mV
-10 V to +10 V & 0 mA to 20 mA
Order Now
3B40-03 -100 mV to +100 mV
-10 V to +10 V & 0 mA to 20 mA

* *
Order Now 3B41-00 Externally Programmable2
-10 V to +10 V & 0 mA to 20 mA
Order Now
3B41-01 -1 V to +1 V
-10 V to +10 V & 0 mA to 20 mA
Order Now
3B41-02 -5 V to +5 V
-10 V to +10 V & 0 mA to 20 mA
Order Now
3B41--03 -10 V to +10 V
-10 V to +10 V & 0 mA to 20 mA

3B41-Custom * *

1 Output current range may be user programmed to 4 mA to 20 mA using jumper supplied.
2 Requires AC1310 ranging card.

* Custom Input/Output ranges are available. Refer to the Configuration Guide.

3B39 Specifications

(typical @ +25°C and ±15 V dc, and +24 V dc Power)

Description  Model 3B30 Model 3B31 
Input Range
Standard Ranges
±10 mV to ±1 V ±1 mV to ±10 V
Custom Ranges
±5 mV to ±1 V ±0.5 V to ±20 V
Output Range
Voltage (RL > 2 kΩ)
-10 V to +10 V
Current (RL = 0 to 850 Ω)1
4 mA to 20 mA or 0 mA to 20 mA
Maximum Current Output Span
0 mA to 31 mA
Initial @ +25°C
±0.1% Span
±0.02% Span
Stability vs. Temperature
Voltage Output
   Input Zero ±2 µV/°C (RTI)
±10 µV/°C (RTI)
   Output Zero ±25 µV/°C (RTI)
±25 ppm of Reading/°C
Zero and Span Adjustment Range4 ±5% of Span
Input Bias Current
=5 nA
Input Resistance
200 M Ω
250 kΩ
Input, 10 MHz Bandwidth
5 µV rms
Output, Ripple and Noise
25 mV peak-to-peak *
Bandwidth, -3 dB 10 kHz
Output Rise Time, 10% to 90% Span
55 µs
Common Mode Voltage (CMV)
Input-to-Output, Continuous
±1500 V peak, maximum
ANSI/IEEE C37.90.1-1989
 Common Mode Rejection (CMR)
1 kΩ Source Imbalance, 50/60 Hz 100 dB 85 dB
Input Protection
220 V rms, maximum
 Transient ANSI/IEEE C37.90.1-1989 *
Voltage Output Protection Continuous Short to Ground
Current Output Protection
130 V rms, continuous
Power Supply Voltages5
±15 V dc Supplies
   Rated Operation ±(11.5 V dc to 16.5 V dc)
   Current ±10 mA
   Sensitivity ±0.01% span/V
+24 V dc Loop Supply
   Rated Operation +12 V dc to +30 V dc
   Current +27 mA @ lout = 20 mA
   Sensitivity ±0.0002% span/V
Mechanical Dimensions
3.15" x 3.395" x 0.775"
(80.0 mm x 86.2 mm x 19.7 mm)
Temperature Range
   Rated Performance -25°C to +85°C
   Storage -55°C to +85°C
Relative Humidity, 24 hours
0 to 95% @ +60°C noncondensing
RFI Susceptibility
±0.5% Span error @ 400 MHz, 5 Watt, 3 ft

* Specifications same as model 3B40.
1 For a 0 to 20 mA range, a typical minimum output current is 10 µA.
2 Includes the combined effects of repeatability, hysteresis, and nonlinearity.
3 With respect to the voltage output.
4 A wide range of custom zero suppression and span is available with the 3B40-00 and 3B41-00 models, using the AC1310 ranging card.
5 +24 V dc loop power is required for driving the current output at loads up to 850Ω. If a current output load of 400Ω or less is applied, +15 V dc is sufficient for loop power. If only voltage output is used, loop power is not required.

Specifications subject to change without notice.