eXRCPU

Main Processor Layer

Special Features

  • 16 simultaneously-sampled, low-level differential analog inputs from ±0.000625 to ±10 V
  • 96 automatic gain states ensuring use of the fullest possible A/D converter range
  • Sampling rates up to 100 kHz
  • 24-bit A/D converter per channel across full-scale range
  • 25 kHz, 8-pole analog Butterworth low-pass filter
  • Software selectable sample rates, digital filtering, excitation voltage and shunt resistance

Detailed description

The eDAQXR family is the next generation in the HBM eDAQ product line of rugged, mobile data acquisition modules. The EBRG bridge layer provides significant improvements in data throughput, supports seamless networking and a state of the art web-based interface. The layer allows flexible configurations for a variety of applications.

In this eDAQXR bridge layer, each of the 16 connectors has both 120-Ohm and 350-Ohm completion resistors connected to a different pin. Formerly, four (4) different eDAQ bridge layers supported the 120-Ohm or 350-Ohm completion resistors and analog output.

The EBRG layer offers 16 simultaneously sampled low-level differential analog inputs through independent connectors. An extremely versatile layer; the layer works with both amplified and unamplified transducers including: strain gauges, accelerometers, pressure transducers, load cells, and other general analog signals. The EBRG provides excellent strain gage conditioning with support for quarter-, half- and full-bridge configurations. Automatic balancing and gain settings as well as software selectable sample rates, excitation, and digital filtering; simplify the set-up of a strain channel. There are several calibration options including defined value, external and multipoint calibrations as well as shunt calibrations with embedded software tools. The EBRG also provides four shunt calibration resistors per channel with software selectable shunt direction for either upscale (-Sig to -Ex) or downscale (-Sig to +Ex) calibrations.

This layer includes an analog output function. Outputs are filtered analog output signals that can be used in the creation of time-domain lab durability tests. When setting up the laboratory simulation, bring the eDAQXR system into the lab with the component or vehicle. This practice is highly recommended, as it ensures that all of the transducer instrumentation and properties are identical for the lab simulation as they were for the field data collection. Instead of being recorded, the analog out signals are sent as time series data for the test rig to analyze. The controller can then develop drive files that are played into the test rig reproducing exact field dynamics in the lab. Each output channel is associated with the corresponding (like-numbered) input channel on the EBRG board. Calibration files, directly compatible with popular simulation software, that scale the analog outputs to engineering units are provided. The maximum analog output voltage is ±10 volts. Each of the 16 analog channels contain a three-pole Butterworth filter which attenuates frequencies above 25 KHz. These filters smooth out the stair-steps created by the channel’s digital to analog converter.

Ordering Options

Ordering Number Description
1-EXR-EBRG-2 eDAQXR Bridge Layer
Includes: Six (6) M3 8mm screws and sixteen (16) 2 m transducer cable (1-SAC-TRAN-MP-2-2)
1-SAC-TRAN-MP-2-2 Transducer Cable - Male/Pigtail - 2 Meters Length
1-SAC-TRAN-MP-10-2 Transducer Cable - Male/Pigtail - 10 Meters Length
1-SAC-TRAN-AO-2-2 Transducer Cable - Analog Out - 2 Meters Length
1-EBB-AO-2 Breakout box - Analog Output eDAQ EHLS Layers
1-SAC-EXT-MF-0.4-2 Extension Cable - Male/Female Connectors - 0.4 Meters Length
1-SAC-EXT-MF-2-2 Extension Cable - Male/Female Connectors - 2 Meters Length
1-SAC-EXT-MF-5-2 Extension Cable - Male/Female Connectors - 5 Meters Length
1-SAC-EXT-MF-10-2 Extension Cable - Male/Female Connectors - 10 Meters Length
1-SAC-EXT-MF-15-2

Extension Cable - Male/Female Connectors - 15 Meters Length

Specifications

Parameter Units Value
Storage temperature range °C [°F] -40 ... +85 [-40 ... +185]
Operating temperature range
   Altitude de-rating
        maximum temperature a 0 m
        maximum temperature a 2500 m
        maximum temperature a 5000 m
°C [°F]
-
°C [°F]
°C [°F]
°C [°F]
-40 ... +80 [-40 ... +176]
-
+80 [+176]
+70 [+158]
 +55 [+131]
Relative humidity range % 5 ... 100
Protection class - III
Degree of protection - IP65/IP67 per EN 60529:2005 (When the eXRCPU is attached to
eDAQ-Plus layers (EBRG, EHLS, EDIO, EITB, ENTB) the
IP rating is downgraded to IP54)
FCC class for digital devices
    eXRCPU and eDAQXR layers
    eXRCPU with eDAQ-Plus layers
-
-
-
-
Class B, eXRCPU alone or attached to eDAQXR layers
Class A, when the eXRCPU is attached to eDAQ-Plus layers (EBRG, EHLS, EDIO, EITB, ENTB)
EMC requirements - CE conformity test per EN 61326-1:2012
Evaluated for safety according to - IEC61010-1:2010
Mechanical test
    Vibration
        acceleration
        duration
        frequency
    Shock
        acceleration
        pulse duration
        number of impacts
-
-
m/s2
min
Hz
-
m/s2
ms
-
-
accord. MIL-STD202G, Method 204, Test Condition D
100
450
5 ... 2,000
accord. MIL-STD202G, Method 213B, Test Condition H
750
6
18
Load dump - ISO 16750-2:2010 Test B 63 Vpeak
Dimensions (H x W x D) mm 68 x 197 x 200 with base and lid
Weight g [lb] 2,004 [4.42] with base and lid
Bridge excitation voltage
     voltage
     initial tolerance (3σ)
     single 5-V temperature drift (1σ)
     single 5-V temperature drift (3σ)
     single 2.5-V temperature drift (1σ)
     single 2.5-V temperature drift (3σ)
     ±5-V temperature drift (1σ)
     ±5-V temperature drift (3σ)
     ±2.5-V temperature drift (1σ)
     ±2.5-V temperature drift (3σ)
-
V
%
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
-
±2.5 or ±5
0.1
5
15
3.3
10
10
30
6.66
20
Quarter-bridge completion resistance
     resistance
     initial tolerance (1σ)
          initial tolerance (3σ)
     temperature drift (1σ)
     temperature drift (3σ)
-

%
%
ppm
ppm
-
120 or 350
±0.0033
±0.01
±0.3
±0.9

Specifications (Continued)

Parameter Units Value
Half-bridge completion resistance
     internal resistance
     typical initial tolerance (1σ)
     maximum intial tolerance
     temperature drift (1σ)
     temperature drift (3σ)
-

%
%
ppm
ppm
-
12.5 (50-kΩ split)
±0.025
±0.05
±0.66
±2
Shunt calibration resistance
     resistance
     initial tolerance (1σ)
     intial tolerance (3σ)
     temperature drift (1σ)
     temperature drift (3σ)
-

%
%
ppm
ppm
-
49.9, 100, 200 and 499
0.033
0.1
10
30
Analog out accuracy % of full scale 0.25
Analog inputs surviving over voltage V ±125
Maximum excitation output power per channel mW 300
Maximum current output mA 42
Power consumption 1
     no load
     350-Ω full bridge at ±5 V
     350-Ω 1/2 or 1/4 bridge at ±5 V
     350-Ω full bridge at ±2.5 V
     350-Ω 1/2 or 1/4 bridge at ±2.5 V
     120-Ω full bridge at ±2.5 V
     120-Ω 1/2 or 1/4 bridge at ±2.5 V
-
W
W
W
W
W
W
W
-
4.55
11.8
8.6
7.1
5.8
12.1
8.6
Typical input offset current over temperature 2 3 pA/°C ±8
Typical input-referred voltage drift over temperature (1σ) 2 4 5
μV/°C
±0.25+1.5/G1
Gain drift over temperature 2
     typical (1σ)
     maximum (3σ)
-
ppm/°C
ppm/°C
-
2.5
10
Analog output channel impedance 6 Ω 1000 ±50

1 Power consumption measurements are taken with the stated load on all 16 channels and include the efficiency of the power supply.

2 Quantities are given per °C temperature change from the temperature at calibration.

3 Use change over temperature to calculate the offset voltage over temperature. Offset voltage [V] = current change over temperature [pA/°C] x change in temperature [Δ°C] x input resistance [10 kΩ].

4 Where G1 is the gain of the first stage. See the gain table in the following section for selected gain settings.

5 The total input referred voltage drift is a combination of drift over temperature at the gain setting [μV/°C] and the drift due to the input current change over temperature (discussed in 3).

6 The 1000-Ohm stabilization resistor in series with the op-amp at the analog output creates an RC filter in addition to the output filter. Typical cable capacitances (Ccable) fall within 18 to 40 picofarads per foot, creating a pole at 1/(2π1000Ccable).

Selected gain settings

Desired Input Range 7 (Vpp)

Input Stage Gain, G1
(1, 10 or 100)

Second Stage Gain, G2
(1/5, 2/5, 4/5 or 1)

Third Stage Gain, G3
(1, 2, 4, 5, 8, 10, 16 or 32)

Overall Gain

20

1

1/5

1

0.2

10

1

2/5

1

0.4

5

1

4/5

1

0.8

4

1

1

1

1

2

1

1

2

2

1.25

1

4/5

4

3.2

1

1

1

4

4

0.8

1

1

5

5

0.625

1

4/5

8

6.4

0.5

1

1

8

8

0.4

10

1

1

10

0.25

1

1

16

16

0.2

10

1

2

20

0.125

1

1

32

32

0.1

10

1

4

40

0.08

10

1

5

50

0.0625

10

4/5

8

64

0.05

10

1

8

80

0.04

100

1

1

100

0.025

10

1

16

160

0.02

100

1

2

200

0.0125

10

1

32

320

0.01

100

1

4

400

0.008

100

1

5

500

0.00625

100

4/5

8

640

0.005

100

1

8

800

0.004

100

1

10

1000

0.0025

100

1

16

1600

0.00125

100

1

32

3200

7 The maximum A/D converter input, which is the product of the input stage and the overall gain, is 4.096 Vpp.

Note: This table is a representative list only and does not show all available gain settings. To check the gain settings for a defined channel, see the Test configuration Channel settings in the eDAQXR web interface. “Gain 1” is the input stage gain, “Atten2” is the second stage gain and “Gain2” is the third stage gain.

Channel Noise Characteristics

The input-referred noise and the signal to noise ratio (SNR) are defined by the following two equations:

where GO is the overall gain setting and N is the noise at the input of the A/D converter, defined by one of the following three

equations depending on the gain of the first stage (G1):

 

 

 

and where xn is the cutoff frequency of the digital or analog filter to a specified maximum.

xn Maximum Value Cause
x1 24 kHz analog filter cutoff
x2 13 kHz secondary filter cutoff
x3 15.7 kHz early rolloff of first stage when G1 = 100

 

Note that when selecting the sampling rate in the web interface, the cutoff frequency of the selected filter is one third of the sampling rate.