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.

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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
Bridge and Strain Conditioner Card Selection Guide
Card |
28144 |
28114 |
28124 |
28124-EA | 28154 | 28108 |
28118 |
28458 |
Type |
AC/DC Voltage with Const. Voltage and Current Excitation |
AC/DC Voltage with Const. Voltage and Current Excitation |
AC/DC Voltage with Const. Voltage and Current Excitation |
Enhanced Accuracy AC/DC Voltage with Const. Voltage and Current Excitation |
AC/DC Voltage with Const. Voltage and Current Excitation | AC/DC Voltage with Const. Voltage Excitation |
AC/DC Voltage with Const. Voltage Excitation |
AC/DC Voltage with Const. Voltage Excitation |
Common Mode Voltage Range | 10 V |
10 V |
10 V |
10 V |
300 V |
10 V |
10 V |
10 V |
Channels/ Card |
4 |
4 |
4 |
4 |
4 |
8 |
8 |
8 |
Applicable Transducer |
Static or dynamic strain w/ BCC™, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor |
Static or dynamic strain w/ BCC™, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor |
Static or dynamic strain w/ BCC™, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor |
Static or dynamic strain w/ BCC™, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor |
Static or dynamic strain w/ BCC™, pressure, RTD, load, accel, AC/DC filter/amp, any bridge type sensor |
Strain, pressure, RTD, load, accel, AC/DC filter/amp, any full bridge type sensor |
Strain, pressure, RTD, load, accel, AC/DC filter/amp, any full bridge type sensor |
Dynamic strain, w/ BCC™, AC 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 |
2-10 Wire Constant Voltage w/ Programmable Bridge Completion, Shunt Cal, 2/4 Wire Constant |
2-10 Wire Constant Voltage w/ Programmable Bridge Completion, Shunt Cal, 2/4 Wire Constant |
2 to 6 wire w/ Shield |
2 to 6 wire w/ Shield |
2 wire w/ Shield |
Excitation |
Constant Voltage: BCC: 0 to 20.475mA |
Constant Voltage: BCC: 0 to 20.475mA |
Constant Voltage: BCC: 0 to 20.475mA |
Constant Voltage: BCC: 0 to 20.475mA |
Constant Voltage: BCC: 0 to 20.475mA |
Constant Voltage: 0 to 20.475 V |
Constant Voltage: 0 to 20.475 V |
BCC: 0,5,10,15,20 mA |
Bandwidth |
>1.5 MHz |
190 kHz |
250 kHz |
250 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/ 0.0125% Resolution |
x1/16 to x8192 w/ 0.003% Resolution |
x1/16 to x8192 w/ 0.0125% 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-Pole Low-Pass with optional REZCOMP, 8-Pole Low-Pass or 8-Pole Band-Pass |
4-poles; FLAT/PULSE |
4-poles; FLAT/PULSE |
8-poles; FLAT/PULSE |
4-poles; FLAT/PULSE Low-Pass |
4-Pole; FLAT/PULSE |
4-Pole, FLAT/PULSE |
4-Pole; FLAT/PULSE |
Cutoff Frequencies |
FLAT: PULSE: |
FX02: FX03: |
FLAT: PULSE: |
FLAT: PULSE: |
FLAT: PULSE: |
FLAT: PULSE: |
FX02: FX03: |
FX02: FX03: |
Outputs |
Single ended with Ground Sense |
Single ended with Ground Sense |
(3) Buffered Prog WB/Filtered SE Outputs per channel w/ Ground Sense |
(3) Buffered Prog WB/Filtered SE Outputs per channel w/ Ground Sense |
(3) Buffered Prog WB/Filtered SE Outputs. Optional isolated output |
Single-ended or Differential Output (Option T) |
Single-ended or Differential Output (Option T) |
(2) Buffered Single-Ended Outputs per Channel |