Bridge Conditioners with Voltage Excitation

Precision 28000 Solutions for Bridge and other Transducers Requiring Constant Voltage Excitation

Where applications call for high performance, high channel-density bridge conditioning, the 28108 and 28118 octal filter/amplifiers with constant voltage excitation deliver low-noise and DC stability for either AC or DC bridge-based sensor or low-level voltage measurements. Stable and accurate balanced constant voltage excitation with remote sense is individually regulated and programmable per channel. Low-noise and low-drift amplification is distributed before and after the low-pass filter, providing protection against out-of-band noise. FLAT/PULSE low-pass filter technology with outstanding channel-to-channel matching for correlation measurements. Fully programmable filter cutoff frequencies with filter bypass for wideband measurements.

The 28108 provides low noise, high CMRR performance with gain settings from x1/16 to x8192 and 255 unique cutoff frequencies. The lower cost 28118 has gain settings from x1/16 to x1024 with five programmable cutoff frequencies.

The 28108 and the 28118 are members of the Precision 28000 family of signal conditioners.

Learn more about the 28000 Signal Conditioning System >

The 28108 and the 28118 with Option 4 Bridge Conditioners with Voltage Excitation

APPLICATIONS:
- Underwater Acoustics
- Pyroshock Measurements
- Ballistics
- Vehicle Vulnerability/ Survivability
- Rotating Machinery Test
- Automatic Test Equipment
- Industrial Process Control
- Anti-aliasing Filter/Amplifier
TRANSDUCERS:
- Strain Gage
- Static/Dynamic Pressure Transducers
- Piezoresistive Accelerometers
- Resistance Temperature Detectors (RTD)
- MEMS Sensors
- Load Cell Sensors

Bridge Conditioners with Voltage Excitation Features:

28108 8-Channel Bridge Conditioner Features:

Eight channels per card, 128 channels per 28016 chassis
Balanced differential inputs with 2 to 6-wire plus shield transducer input interface.
Balanced (zero common-mode) programmable constant voltage excitation. Up to 20V delivered to the bridge.
Automatic bridge balance/Zero suppress via a programmable DC voltage inserted at the channel input
Distributed programmable gain of x1/16 to x8192 with 0.05% resolution
Input MUTE mode to terminate unused channels in safe, quiet state
Pre-filter overload detection
4-pole low-pass filters with programmable flat/pulse characteristics for optimized time domain or frequency domain performance. Programmable low-pass filter cutoff frequencies:
Pulse Mode: Programmable from 50 Hz to 12.75 kHz
Flat Mode: Programmable from 100 Hz to 25.5 kHz
wideband (100 kHz) or filtered operation
Precise digital calibration
Single-ended outputs with ground sense or optional differential output
Programmable test modes for cal signal injection, excitation monitor, excitation off and input short, allowing for automated measurement system validation
Output monitor bus
Auxiliary front panel output connection supports the use of Precision Filters’ output buffer modules for adding up to two buffered outputs per channel (for units without option 4)

View the 28108 8-Channel Bridge Conditioner Specification Sheet >

28118 8-Channel Bridge Conditioner Features:

Eight channels per card, 128 channels per 28016 chassis
Balanced programmable constant voltage excitation with remote sense
Up to 20 V delivered to the bridge
±10 Vcm operation
Up to 30 kHz “filtered” bandwidth or 190 kHz “wideband” bandwidth
2- to 6-wire plus shield transducer input interface
Automatic bridge balance/transducer suppress
Programmable amplifier: x1/16 to x1024 with 0.05% vernier
Distributed gain to provide reserve against out-of-band signal such as transducer resonances
4-pole low-pass filters with programmable flat/pulse characteristics
2° phase matching between any channels
Overload detection
Auxiliary front-panel output connection to support the use of custom output modules (for unit without option 4)

View the 28118 8-Channel Bridge Conditioner Specification Sheet >

28108 and 28118 Comparison Chart

Card	28108	28118
Type	AC/DC Voltage, Bridge, Static Strain, Dynamic Strain	AC/DC Voltage, Bridge, Static Strain, Dynamic Strain
Channels/Card	8	8
Applicable Transducer	Static Strain, Pressure, RTD, Load, Accelerometer, AC/DC Filter/Ampifier, any Full Bridge Type Sensor	Static Strain, Pressure, RTD, Load, Accelerometer, AC/DC Filter/Ampifier, any Full Bridge Type Sensor
Interface	2 to 6 Wire w/ Shield	2 to 6 Wire w/ Shield
Excitation	Constant Voltage: 0 to 20.475 V	Constant Voltage: 0 to 20.475 V
Bandwidth	100 kHz	190 kHz
Gain	x1/16 to x8192 w/ 0.05% Resolution	x1/16 to x1024 w/ 0.05% Resolution
Filter	4-Pole, FLAT/PULSE Low-Pass	4-Pole, FLAT/PULSE Low-Pass
Cut Off Frequencies	FLAT: 2 Hz to 204.6 kHz PULSE: 1 Hz to 102.3 kHz	FX02: 300, 1k, 3k, 10k, 30 kHz*
Outputs	Single-ended or Differential Output (Option T)	Single-ended or Differential Output (Option T)

* Custom cutoff frequencies are available. Please consult factory.

Bridge and Strain Conditioner Card Selection Guide

Card	28144	28114	28124	28108	28118	28458
Type	AC/DC Voltage, Bridge, Static Strain, Dynamic Strain	AC/DC Voltage, Bridge, Static Strain, Dynamic Strain	AC/DC Voltage, Bridge, Static Strain, Dynamic Strain	AC/DC Voltage, Bridge, Static Strain	AC/DC Voltage, Bridge, Static Strain	AC Voltage, Dynamic strain
Channels/ Card	4	4	4	8	8	8
Applicable Transducer	Static or dynamic strain, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor	Static or dynamic strain, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor	Static or dynamic strain, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor	Static strain, pressure, RTD, load, accel, AC/DC filter/amp, any full bridge type sensor	Static strain, pressure, RTD, load, accel, AC/DC filter/amp, any full bridge type sensor	Dynamic strain, AC/DC filter/amp
Interface	2-10 Wire Constant Voltage w/ Programmable Bridge Completion, Shunt Cal, 2/4 Wire Constant Current	2-10 Wire Constant Voltage w/ Programmable Bridge Completion, Shunt Cal, 2/4 Wire Constant Current	2-10 Wire Constant Voltage w/ Programmable Bridge Completion, Shunt Cal, 2/4 Wire Constant Current	2 to 6 wire w/ Shield	2 to 6 wire w/ Shield	2 wire w/ Shield
Excitation	Constant Voltage: 0 to 20.475V; Balanced Constant Current: 0 to 20.475mA	Constant Voltage: 0 to 20.475V; Balanced Constant Current: 0 to 20.475mA	Constant Voltage: 0 to 20.475V; Balanced Constant Current: 0 to 20.475mA	Constant Voltage: 0 to 20.475 V	Constant Voltage: 0 to 20.475 V	Balanced Constant Current: 0,5,10,15,20 mA
Bandwidth	500 kHz	190 kHz	250 kHz	100 kHz	190 kHz	190 kHz
Gain	x1/16 to x8192 w/ 0.05% Resolution	x1/16 to x1024 w/ 0.05% Resolution	x1/16 to x8192 w/ 0.05% Resolution	x1/16 to x8192 w/ 0.05% Resolution	x1/16 to x1024 w/ 0.05% Resolution	x1/16 to x1024 w/ 0.05% Resolution
Filter	4, 8-poles; FLAT/PULSE Low-Pass or BP	4-poles; FLAT/PULSE Low-Pass	4-poles; FLAT/PULSE Low-Pass	4-Pole; FLAT/PULSE Low-Pass	4-Pole, FLAT/PULSE Low-Pass	4-Pole; FLAT/PULSE Low-Pass
Cutoff Frequencies	FLAT: 2 Hz to 204.6 kHz PULSE: 1 Hz to 102.3 kHz	FX02: 300, 1k, 3k, 10k, 30 kHz*	FLAT: 2 Hz to 204.6 kHz PULSE: 1 Hz to 102.3 kHz	FLAT: 2 Hz to 204.6 kHz PULSE: 1 Hz to 102.3 kHz	FX02: 300, 1k, 3k, 10k, 30 kHz*	FX02: 300, 1k, 3k, 10k, 30 kHz*
Outputs	Single ended with Ground Sense	Single ended with Ground Sense	(3) Buffered Prog WB/Filtered SE Outputs per channel w/ Ground Sense	Single-ended or Differential Output (Option T)	Single-ended or Differential Output (Option T)	(2) Buffered Single-Ended Outputs per Channel
					Single-ended or Differential Output (Option T)	(2) Buffered Single-Ended Outputs per Channel