3B16 Narrow Bandwidth, Strain Gage Input

The 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.

Figure 1. 3B16 Functional Block Diagram

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

	Model	Input Bridge	Input Range	Excitation	Sensitivity	Output  Ranges1
Order Now	3B16-00	Full Bridge	Externally Programmable2	+10 V	Externally Programmable2	-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
	3B16-Custom	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.

(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
Accuracy2
Initial @ +25°C	±0.1% Span
Nonlinearity2	±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
Voltage	+10 V
Voltage, tolerance	±2%
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
Noise
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
Continuous	130 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	±(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)
Environmental
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