Dynamic Strain with Current Excitation

Precision 28458 Solution for Measuring Dynamic Strain

Precision’s Balanced Constant Current™ technology is available in the high-density 8-channel 28458 card. Measurements of dynamic strain are much less susceptible to EMI pickup and lead resistance desensitization that plagues single-ended constant current topologies. The 28458 features Precision’s “on-the-fly” measurement of transducer resistance, excitation and leakage resistance, alerting the operator immediately to an out-of-tolerance condition. AC dither current provides for evaluation of true sensor plus cable frequency response. Fully programmable FLAT/PULSE filters with distributed gain for out-of-band noise protection.

The 28458 is a member of the Precision 28000 family of signal conditioners.

Learn more about the 28000 Signal Conditioning System >

28458 8-Channel Conditioner with Balanced Constant Current Excitation

MEASUREMENTS:
- Dynamic Strain Gage Conditioner
- High Temperature Strain Gage Conditioner
- Dynamic Hot Wire Anemometry
- AC/DC Filter/Amplifier

28458 8-Channel Conditioner with Balanced Excitation Features:

Eight channels per card
128 channels per 28016-M3 or 28016-M5 mainframe,
64 channels per 28008-M3/M5 mainframe,
32 channels per 28004-M3/M5 mainframe
AC coupled balanced differential input
Balanced differential constant current excitation
Excitation disconnect for voltage/amp operation
AC current test mode for verifying transducer, cabling and frequency response
On-the-fly report of measured transducer excitation and resistance
Transducer open/short indication
Transducer leakage to ground detection
4-pole flat/pulse low-pass filter (LP4FP) with cutoff options from 100 Hz to 100 kHz
Bypass filter for wideband amplifier operation (–3dB @ 190 kHz)
Voltage substitution test signals
Programmable amplifier: x1/16 to x1024 with 0.05% vernier
2° phase matching between any channels
Pre-filter overload detector to report out-of-band overloads which the filter could mask
Dual buffered outputs

View the 28458 Specification Sheet >

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: 100 Hz to 25.5 kHz PULSE: 50 Hz to 12.75 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

* Custom cutoff frequencies are available. Please consult factory.

Dynamic Strain with Current Excitation

MEASUREMENTS:

28458 8-Channel Conditioner with Balanced Excitation Features:

Bridge and Strain Conditioner Card Selection Guide