Pacific Instruments, Inc. Pacific Instruments, Inc.
4080 Pike Lane
Concord, CA 94520
www.pacificinstruments.com
(925) 827-9010
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Products > High Speed Data Acquisition & Control Systems > High Speed Data Acquisition & Control System I/O Modules > Model 6739  


Model 6739, 8-Channel Strain/Bridge Transducer Amplifier-Filter-Digitizer

Features

  • Programmable input configuration, ¼, ½ & full bridge
  • Programmable voltage excitation with remote sensing
  • Additional ±12 or ±15 Volt transducer power
  • Two-step shunt & voltage substitution calibration
  • Gains 1 to 5,000 with 0.01% to 0.02% accuracy
  • 9 digital Butterworth filters
  • Up to 250 kS/s per channel with 24-bit resolution
  • Two alarms with programmable upper & lower limits
  • Digital alarm output option

Description

The 6739 input module has eight channels of high performance signal-conditioning amplifier-digitizers for strain gages and bridge transducers. Each channel has programmable excitation with remote sensing, voltage and shunt calibration, programmable gain instrumentation amplifier. Analog output is digitized to 24 bits then provided to the 6700 data bus. The filter is programmable providing 9 digital Butterworth filters and wideband.

The 6739 is used with ¼ (120 and 350 Ohm s/w selectable), ½ and full bridge transducers, potentiometers and low-level voltage signals in demanding, dynamic measurement applications. It is particularly suited to strain gages and bridge transducers. A shielded eight-wire input provides independent excitation, sense, calibration and signal connections to the transducer. Excitation is programmable from 0 to 12 Volts with remote sensing providing regulated excitation at the transducer. The input connector also provides access to ±12 or ±15 or 28 Volt DC power.

Gain calibration may be done by voltage substitution using an external voltage standard. A calibration attenuator enables the voltage standard to be used on its highest accuracy ranges and has a post-attenuator output for accuracy verification. Two steps of bipolar resistive shunt calibration are provided for transducer calibration. Calibration and gain and zero correction can be automated using software such as Pacific’s PI660. Two alarms with programmable upper and lower limits are provided.





Overview  · Input  · Excitation/Transducer Power  · Amplifier  · Filter  · Digitizer  · Calibration  · Mechanical  · Ordering Information 

Overview

Measurement Type
Bridge
Position
Strain Gage

Excitation/Transducer Power
±12V
±15V
28V
Voltage

Filter
9 digital Butterworth

Sample Rate (Digitizer)
250 kS/s


Input

Configuration
8 channels, 2 to 8 wire with guard shield. Bridge config is programmable for ¼, ½ and full bridge. 120 and 350 Ohm completion resistor standard, alternate value may be specified.

Balance
Automatic by program control. Balance accuracy ±0.05% of range, ±1 mV RTO. Stability ±0.02% for 8 hours, ±0.005%/°C. Coarse and fine balance are jumper selectable.

Impedance
10M Ohm shunted by 500 pF.

Protection
±50 Volts differential, ±50 Volts common mode. Optional lightning protection. Card-to-card common mode voltage 300V.


Excitation/Transducer Power

Voltage Excitation
Programmable per channel from 1-12 Volts in 1 Volt steps with 1.2 mV accuracy, or adjustable with 3.3 mV resolution.

Current
50 mA limited to 70 mA.

Regulation
±0.01% for ±10% line and no-load to full-load using remote sensing.

Stability
±0.005%, ±12 µV/C

Voltage Excitation Noise
200 µV peak-to-peak (not individually tested)

Monitor
Calibration mode measures excitation voltage with ±0.2% accuracy

Transducer Power
±12 or ±15 Volts or 28V jumper selectable per module.

Current (Transducer Power)
200 mA maximum per card.

Configuration (Transducer Power)
Transducer power available on separate pins from voltage excitation.


Amplifier

Gain
Gains 1 to 500 ±0.01%. Gains 1 to 5000 ±0.02%.

Gain Stability
±0.01%, ±0.004%/ºC.

Linearity (Amplifier)
±0.01% for gains < 1,000, ±0.02% for gains 1,000 and higher.

Common Mode
Better than 80dB (between input & excitation ground).

Zero (Amplifier)
Automatic to ±1 µV RTI, ±0.5 mV RTO.

Zero Stability
Better than than ±1µV/°C RTI

Source Current
±10 nA, ±1 nA/ºC.

Noise (10 Hz)
0.1 µV rms RTI, 0.5 mV rms RTO.

Noise (1 kHz)
1.0 µV rms RTI, 0.5 mV rms RTO

Bandwidth
>5 kHz

Slew Rate
>10 V/µS

Analog Output
±10 Volts full scale, 20 mA

Recovery
120 µS to ±0.1% for 10X overload to ±10 V.


Filter

Type
9 digital Butterworth

Frequency
10 Hz to 1 kHz

Other
Other filter characteristics and cut offs are available.


Digitizer

Sample
Simultaneous, within ±50 nS channel-to-channel. Droop is less than ±0.005%.

Resolution
24-bits, two's complement.

Sample Rate
Up to 250 kS/s per channel

Continuity
No Missing Codes

Alarms
Two alarms each with programmable upper and lower limits and persistence checked on each ADC sample.


Calibration

Shunt
Two step bipolar shunt with 0.05% resistors. Nominal deflection is 0.5025 mV/V and 0.245 mV/V for 350 Ohm bridge, and 0.17235 mV/V and 0.08402 mV/V for a 120 Ohm bridge.

Voltage Substitution
Attenuator accuracy is 0.02% for 1 and 0.01% for 0.1 and 0.01.

Zero Calibration
Amplifier input disconnected and shorted.


Mechanical

Mounting
Occupies one slot in Series 6700 enclosures.

Connectors
Four D-subminiature connectors, compatible with 6000 series pinouts. Two 50 position transducer socket, one 9-position analog output socket, one 9-pin status output. Other connector arrangements are possible.

Operating Temperature
0 to +50 ºC


Ordering Information 

Ordering Information
6739 - 8-Ch Strain-Bridge-Position, 9 Freq Digital Butterworth Filter

Pacific Instruments, Inc. · 4080 Pike Lane · Concord, CA 94520 · www.pacificinstruments.com