3B16 Narrow Bandwidth, Strain Gage Input


Model 3B16-01The 3B16 is a single-channel signal conditioning module which interfaces, amplifies, and filters signals from 4-arm full-bridge strain-gage bridges with a resistance from 300 Ω to 1 kΩ. The module provides a constant +10 V bridge excitation voltage and provides simultaneous precision voltage and current outputs. The user-configurable Model 3B16-00 can be applied in applications involving large tare weights which must be compensated with zero suppression. The 3B16 protects the computer side from damage due to field-side overvoltage faults up to 130 V rms. In addition, the current output withstands 130 V rms without damage and interfaces user equipment through screw terminals located on the 3B Series backplane. The 3B16 is a plug-in, mix-and-match, hot-swappable module which is easily field calibrated via front-panel zero and span adjustments for both voltage and current outputs.

3B Series Custom-Ranging Program

Externally-programmable Model 3B16-00, enables the user to configure a special input range, including tare weight suppression, 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 3B16 Series 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 (Model 3B16-CUSTOM) or can be externally programmed (Model 3B16-00) via user supplied resistors inserted in the optional AC1310 plug-on ranging card. Internal lowpass filtering with a 3 Hz cutoff (-3 dB) two-pole Butterworth filter enhances a 60 dB normal-mode rejection at 50/60 Hz, enabling accurate measurement of small signals in high electrical noise.

Input and Output Ranges

3B16 Functional Block Diagram
Figure 1. 3B16 Functional Block Diagram

3B16 Input Field Connections
Figure 2. 3B16 Input Field Connections

Input Type
Dual Outputs
Strain Gage:
-10 V to +10 V
Full 4-Arm Bridge
4 mA to 20 mA or 0 to 20 mA

3B16 Models Available

Model  Input
Excitation Sensitivity Output 
Order Now 3B16-00
Full Bridge

+10 V Externally
-10 V to +10 V &
0 mA to 20 mA
Order Now 3B16-01
Full Bridge
-30 mV to +30 mV
+10 V
3 mV/V
-10 V to +10 V &
0 mA to 20 mA

Full Bridge
* +10 V
* *

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.

3B16 Specifications

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

Description  Model 3B16
Input Range
Standard Range
 ±30 mV (3 mV/V sensitivity @ Vexc = +10V)
Custom Ranges
±5 mV to ±500 mV
Output Range
Voltage (RL > 2 KΩ)
-10 V to +10 V
Current (RL = 0 to 850Ω)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
±0.01% Span
Stability vs. Temperature
Voltage Output
   Zero ±3 µV/°C (RTI)
   Span ±25 ppm of Reading/°C
Current Output3
   Zero  ±25 ppm of Span/°C
   Span ±25 ppm of Reading/°C
Bridge Excitation
+10 V
Voltage, tolerance
Voltage vs. Temperature ±0.0015%/°C
 Bridge Resistance Range
Vexc= +10.0 V  300 Ω to 1 kΩ
Zero and Span Adjustment Range4  ±5% of Span
Input Bias Current  +3 nA
Input Resistance 100 MΩ
Input, 0.1 Hz to 10 Hz Bandwidth
0.2 µV rms
Output, 100 kHz Bandwidth
50 µV rms
Bandwidth, -3 dB
3 Hz
Output Rise Time, 10% to 90% Span
200 ms
Common-Mode Voltage (CMV)
Input-to-Output, Continuous
±10 V peak, maximum
Transient ANSI/IEEE C37.90.1-1989
Normal Mode Rejection @ 50/60 Hz 60 dB
Input Protection, Signal and Excitation Voltage
130 V rms maximum
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 ±(12.7 V dc to 16.5 V dc)
   Current +45 mA, -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

1 For a 0 mA 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 3B16-00 model, 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.