NSG-2916
NETDAS 16-CHANNEL, STRAIN GAUGE
INTERFACE MODULE
OVERVIEW
L-3 Telemetry & RF Products (L-3 T&RF) NSG-2916 is a signal conditioning
module that monitors up to 16 differential strain gauge inputs generating
converted digital output in 16 unique words. The module design utilizes
specialized Digital Signal Processing
(DSP) filtering concepts that provide
performance similar to traditional
analog- based implementations, while
requiring significantly fewer electronic
components. The end result is greater
channel density at a lower cost per
channel, with greater functionality.
Each channel has an input multiplexer
used to select between the external
transducer input and multiple internal
calibration sources. The multiplexer’s output is fed to a programmable gain
stage supporting a total gain between 1 and 1024. The amplified signal is
then passed through an anti-aliasing filter, followed by an Analog-to-Digital
Converter (ADC) operating at a rate of 390.625 ksps and feeding the DSP filter.
To minimize distortion (≤ 72 dB) induced by the frame sampling, the data is
up-sampled from 390.625 kHz to 50 MHz.
Use of U.S. DoD visual information does not imply or constitute DoD endorsement.
The NSG-2916 features a programmable constant voltage excitation source that
provides differential 2 to 10 Vp-p at 30 mA per channel. Each channel provides
a number of calibration and balance features to facilitate programming and
checkout: Zero Calibration (Z-CAL), Substitution Calibration (N-CAL), Voltage
Calibration, Resistor Calibration (R-CAL), transducer balance, transducer offset,
amplifier offset and manual offset. The NCAL DAC is referenced to excitation
and connects to one arm of the strain gauge bridge so that it can provide a
deflection NCAL, as well as provide the usual substitute NCAL.
The NSG-2916 allows the user to enable simultaneous sample and hold, which
provides phase correlation between all similarly configured analog channels
within the entire Data Acquisition Unit (DAU), or within a complete synchronized
NetDAS™ system.
All features of the NSG-2916 are supported by L-3’s Vista TEC™ software,
which includes an operational checkout feature that provides automated testing
of all channels to compare data received and against user specified targets.
FEATURES
• 16 channels of differential analog
signal conditioning inputs from strain
gauges
• Each channel supports inputs up to 10
Vp-p
• Includes constant voltage excitation
source that provides 2 to 10 Vp-p at 30
mA per channel
• Each channel has independent and
user-selectable gain and offset
settings
Telemetry & RF Products
• Programmable settings allow for total
gain from 1 up to 1,024
• Module supports Z-CAL, N-CAL,
R-CAL, transducer balance,
transducer offset, amplifier offset and
manual offset
• Supports simultaneous sample and
hold function on a per-channel basis
• Fully programmable by L-3’s Vista
TEC™ software
NSG-2916
NETDAS 16-CHANNEL, STRAIN GAUGE
INTERFACE MODULE
SPECIFICATIONS
INPUT
Device Compatibility
Full bridges only. User must supply external bridge complete for other configurations. Not compatible with most bridge type sensors beyond strain gauges due to transducer balancing circuit. (i.e. the NCAL DAC)
Full Scale (FS) Range
10 Vp-p / gain
Input Impedance
10 MΩ nominal
Over-Voltage Protection
± 40 V with latch-up protection
GAIN
Selectable Gain
Programmable gain from 1 to 128,
gain of 1 is 10 Vp-p
Accuracy
± 0.5 %
Stability
± 0.75 % of selected value,
including effects of excitation drift
Linearity
± 0.1 % Best Straight Line (BSL)
OFFSET
Channel Offset Stability
± 0.5 % FS over temperature for
gain ≤ 100
± 0.6 % FS over temperature for
gain > 100
Reference to Output (RTO) ± 50 % of FS range
Offset Capability
(offset performed in Field
Programmable Gate Array (FPGA)
before filtering)
Output / Channel Offset
Stability
± 0.5 % FS over temperature
Amplitude Response
Flat within ± 0.5 % from DC to FPB for Fc < 5 kHz
+ 0.5 % / -1% for Fc > 5 kHz
-3 ± ½ dB at Fc
Filter Type
6-pole, low-pass Butterworth
Infinite Impulse Response (IIR) filter
Output Rate
50 Msps
ADC Sample Rate
50 MHz / 128 = 390.625 ksps
EXCITATION
Number of Excitation
Supplies
16
Range (limit in Vista TEC) Dual tracking, positive and negative
single-ended supplies
Individually programmable from
1 V to 5 V ~229 µV per step in 16-bit system, capable of providing 2 to 10 V of differential excitation.
Accuracy
± 0.5 %
Load Regulation
± 0.5 % from 1 kΩ load to full load
of 30 mA, 2 to 10 Vp-p
Current Limit
Between 40 to 75 mA
OUTPUT
16-Bit Conversion
The channel output is converted to a 16-bit word, either straight binary or 2s complement
Note: Full-scale signal is converted into 15 bits, with remaining
bit used to accommodate offset
Supports either common word size or extended read mode.
Status: Unique measurements that contain current balance
status.
DIGITAL FILTER
Programmable 3 dB Fc = 10 Hz to 8.014 kHz
Cutoff Frequency (Fc)
Spacing of selectable cutoffs, 12% Fc
Full Passband (FPB) Defined FPB = 0.6144 x Fc (i.e., FPB is
programmable as 6.144 Hz to 5 kHz)
Inter-Channel Correlation ± 2 degrees, DC to Passband
(between channels configured for
the same Fc)
Stopband
> 2.5 x Fc @ 40 dB minimum
L-3 Telemetry & RF Products
9020 Balboa Avenue
San Diego, CA 92123
Tel: 858.694.7500
800.351.8483
1515 Grundy’s Lane
Bristol, PA 19007
Tel: 267.545.7000
Email: Sales.TRF@L-3com.com
L-3com.com/ TRF
This presentation consists of L-3 Communications Corporation general capabilities information that does not contain controlled technical data as defined within the
International Traffic in Arms (ITAR) Part 120.10 or Export Administration Regulations (EAR) Part 734.7-11 Data, including specifications, contained within this document
are summary in nature and subject to change at any time without notice at L-3’s discretion. Call for latest revision. All brand names and product names referenced are
trademarks, registered trademarks, or trade names of their respective holders. BRML685 Rev A
Telemetry & RF Products