EBRG/ELBRG bridge layers
The EBRG/ELBRG bridge layers offer simultaneously sampled low-level differential analog inputs through independent connectors. These are extremely versatile layers. The layers work with both amplified and unamplified transducers including: strain gauges, accelerometers, pressure transducers, load cells and other general analog signals. The layers provide 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 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 layers also provide four shunt calibration resistors per channel with software selectable shunt direction for either upscale (-Sig to -Ex) or downscale (-Sig to +Ex) calibrations.
The EBRG supports 16 input signals. The ELBRG supports 4 input signals.
The layers support full- and half-bridge types with resistance ranges from 100 to 10000 Ohm, and quarter-bridges with resistance of either 120 or 350 Ohm (as a factory installed option). A set of internal shunt resistors (50, 100, 200, and 500 kOhm) is available for sensor scaling and test setup sanity checks.
Some other features are itemized as follows.
- Differential inputs provided for the analog input signals.
- The EBRG has synchronous sampling with other EHLS, EBRG and EDIO layers. The ELBRG has synchronous sampling with other ELHLS, ELBRG and ELDIO layers.
- Completely flexible configuration of filter type, filter pass bandwidth, and sample rate on a per channel basis.
- For EBRG layer models 02 and above, an optional analog output sub board is available to provide high level analog output signals for each channel.
- For EBRG layer models 02 and above, the excitation is provided on 4 channel Bank basis (i.e., the excitation voltage for Bank 1 [channels 1-4] can be selected independent of the excitation voltages selected for the other three (3) Banks).
Connect transducers to the EBRG/ELBRG individually using the M8 connectors located on the front panel.
Each independent channel contains programmable transducer power, an eight-pole Butterworth analog guard filter, a 16-bit A/D converter, software selectable digital filtering and output sample rate options of up to 100 kHz.
The EBRG/ELBRG layer supports full- and half-bridge types with a resistance from 100 to 10000 ohms and quarter-bridges with a resistance of either 120 or 350 ohms. All bridge configurations are accomplished using programmable switches, however, the quarter-bridge choice of 120- or 350-Ohm completion resistor is a factory installed option. A set of internal shunt resistors with selectable shunt direction is available for calibration purposes.
The diagram shows the M8 connectors on the EBRG layer.
The diagram shows the M8 connectors on the ELBRG layer.
Wiring diagrams
Analog input
Use the Somat SAC-TRAN-MP Transducer Cable (1-SAC-TRAN-MP-2-2 or 1-SAC-TRAN-MP-10-2) to wire EBRG/ELBRG analog inputs.
NOTE
Do not use this wiring diagram for EHLS/ELHLS channels.
Strain gages
Piezoresistive transducers
Analog Output
The EBRG is available with an optional analog output function to provide high level analog output signal for each channel. Outputs are filtered analog output signals that can be used in the creation of time-domain lab durability tests. Each output channel is associated with the corresponding (like-numbered) input channel on the EBRG board. Connect the analog outputs to the EBRG through the Analog Output connector on the back panel shown in the diagram below.
This diagram shows the analog out connector on the back panel of an EBRG layer.
The outputs are generated from a D/A converter implemented as a unity gain follower to the A/D converter. The eDAQXR/eDAQXR-lite uses the non-inverting unity gain follower by default. Select the Analog output inversion option in the test setup configuration to use the inverting unity gain follower when the channel calibration slope is negative.
NOTE
The EBRG uses a nominal ±2-volt A/D converter. However, do not assume that the user-defined full-scale values are even approximately equivalent to ±2 volts for any particular channel. This is primarily because the eDAQXR automatically provides a minimum over range protection of 1% and the eDAQXR can set gains only at certain discrete values resulting in actual over range protection that is sometimes significantly larger than 1%.