gDAS-32

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Technical Specifications

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2 input channels

• Independent 32 bit analogue-digital converters

• Input voltage range: +/- 2.5 V (modifiable to +/- 26 V)

• Maximum continuous input voltage limit: +/- 50 V

• Maximum momentary input voltage limit: +/- 500 V

• Input impedance: 20 MΩ

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Maximum number of samples per time series record: 4 million [2    ] samples

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Sample rate

• User programmable

- Maximum fs: 32 kHz, Time series record length = 128 secnds

-Minimum fs: 8 Hz, Time series record length = 145 hours

• Typical fs for MT acquisition:

- 32 kHz, each time series record length = 128 seconds

- 2 kHz, each time series record length = 34 minutes

- 128 Hz, each time series record length = 9 hours

• Typical fs for IP acquisition:

- 512 Hz, each time series record length = 2 hours

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GPS synchronization

• Maximum GPS error: 100 ns

• Typical (measured) GPS error: 10 ns

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Calibration

• Internal signal generator. +/- 20.48 mV, 0.5Hz for internal calibration and system check

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Contact impedance

• Measured prior to each acquisition and on user command

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Memory / Storage

• Internal pen drive: 8 Gb provides for 200 typical time series filed

• Typical time series file (2 channels, 4 M samples): 35 Mb

• Time series data files: simple 32-bit binary

• Data download: USB cable or removal of pen drive

• Data available for download during acquisition and turned off

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Processors

• Real time acquisition processor Microchip 32-bit 80 MHz

• HMI Processors 32-bit ARM 200 Mhz with light Linux kernel

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Power source

• External battery: 9 to 22 V

Battery type according to application with/without solar panel

• Consumption during acquisition:

- Bluetooth on: 200 mA (12 V supply)

- Bluetooth off: 145 mA (12 V supply)

- XBee external radios: to be defined

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General Specifications

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Dimensions & weight

• External Pelican case with connectors

- 215 x 175 x 100 mm, 1.2 kg

• Internal electronics and housing

- 190 x 124 x 45 mm, .4 kg

 

User interface

• No screen or buttons

• 2 powered RS232 ports, 9600 baud rate

- Internal port for Bluetooth

- External port for XBee (or similar) radio

- Output compatible user-friendly real-time text updated at 1 Hz with status information

- Other comms:

User can send real-time commands (start acquisition, abort, calibrate, contact resistance, etc)

Receive 3-day history of acquisition and system information

Receive a 30s record of binary fs = 256 Hz time series data (non-terminal compatible)

• Schedules (acquisition & communication) and ADC configuration

- User updated by copying a text file to the USB and rebooting gDAS32