Functional Description
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 Strain Gage: Full 4-Arm Bridge |
Dual Outputs -10 V to +10 V 4 mA to 20 mA or 0 to 20 mA |
3B16 Models Available
| 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 | * | * |
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 |
| 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 |
| Trasient | ANSI/IEEE C37.90.1-1989 |
| Voltage Output Protection | Continuous Short to Ground |
| Current Output Protection | 130 V rms, continuous |
| Power Supply Voltages 5 | |
| ±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 |
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