8921-GeoNet-Cellular-Data-Loggers.pdf

www.geokon.com/8921-Series

INTRODUCTION

GEOKON Model 8921 Series Data Loggers offer a high-value, LTE Cat 1 compatible*, networked data collection option for all GEOKON vibrating wire instruments and digital sensor (MEMS IPI and VW) strings. Each data logger comes from the factory ready for deployment and may commence with data acquisition in minutes.

Sensor data is collected and transferred via a cellular network to a secure cloud-based storage platform where it is securely stored.

Data can be viewed in GEOKON Agent Software or exported to a third-party software platform through the Open API.

Commissioning, billing and configuration are accomplished via the easy to use GEOKON API Portal, which allows users to activate data loggers, change settings, configure sensor channels, and view current data logger status.

The API Portal can be found at api.geokon.com and the GEOKON Agent program can be downloaded at www.geokon.com/software.

Model 8960 Digital Vibrating Wire interfaces can be connected to GeoNet multi-channel and addressable data loggers to expand the capacity of the data logger.

Multiple VW interfaces can be daisy-chained together to bus the data to a single data logger. The bus limit is 32 units or 64 channels. Refer to the Model 8960 data sheet for more information.

Available models include:

Single and multichannel Vibrating wire dataloggers that are compatible with most manufacturers' VW sensors.

A digital addressable data logger compatible with GEOKON addressable MEMS, VW, and thermistor sensor strings.

A four-channel analog data logger capable of reading data from analog sensors.

A tilt data logger that combines the functionality of a biaxial tiltmeter and a GeoNet data logger.

A Digital High Power data logger that can read up to 250 GEOKON MEMS sensors. With custom firmware, it is capable of reading non-GEOKON sensors that utilize RS-485 MODBUS communication protocol.

Applications

Typical applications include:

� Groundwater monitoring

� Tailings dams

� Mining/slope stability

� Structural monitoring of buildings, bridges, excavations, and tunnels

� Historical structures

GEONET CELLULAR Data LOGGERS

& DATA ACQUISITION SYSTEM

Model 8921 Series

GeoNet Cellular Data Loggers & Wireless Data Hosting System with Cloud integration and secure data access

*Compatible with all major cellular networks except Verizon

Tilt Data Logger geokon® server + openapi

Secure Cellular Connection

Secure data access and visualization via geokon agent software or optional third party software

Addressable Data Logger

Eight-Channel VW Data Logger geokon 48 Spencer Street Lebanon, NH 03766 • USA www.geokon.com e: teamsales@geokon.com p: + 1 · 603 · 448 · 1562 geokon is an iso 9001:2015 registered company

The geokon ® logo and word mark are registered trademarks with the United States Patent and Trademark Office. | geokon maintains an ongoing policy of design review and reserves the right to amend products and specifications without notice. | The LoRa® Mark is a trademark of Semtech Corporation or its subsidiaries. | LoRaWAN® is a registered trademark of the LoRa Alliance.® Modbus is a registered trademark of SCHNEIDER ELECTRIC USA, INC. | All other trademarks are the property of their respective owners.

Not all models are CE approved. Contact geokon for details.

©geokon. All Rights Reserved. | Rev-A-01/28/2026

ACCESSORIES

8900-SOL-10W-USB: GeoNet Series Solar Panel, 10W, unregulated.

COM-169: USB 2.0 A Male to C Male Cable

KIT-GEONET-C-T20: USB 2.0 A Male to C Male Cable and T20 Screwdriver

8921-01C Single-Channel VW Data Logger

8921-TLT

Tilt Data Logger

8921-DHP

Digital High Power Data Logger

8921-08C Eight-Channel VW Data Logger

8921-ANA

Four-Channel Analog Data Logger

8921-ADR

Addressable Data Logger

AVAILABLE MODELS

Range1 ±90°

Resolution 2 0.00025° (0.004 mm/m)

Precision 3 ±0.0075° (±0.13 mm/m)

Nonlinearity ±0.005° across ±30° range (±0.09 mm/m)

Temperature Dependent Uncertainty

±0.001° across ±5° angular range (±0.016 mm/m) ±0.0016° across ±15° angular range (±0.026 mm/m) ±0.0026° across ±30° angular range (±0.042 mm/m)

Axes 2

1 Calibrated Range: ±30° 2 99% confidence interval (i.e. 99 out of 100 individual readings fall within this tolerance).

3 Includes random walk (changes in consecutive readings with no discernible cause) and seismic noise during testing.

TILT data Logger Specifications

General Specifications

Power Supply DHP models: Internal sealed lead acid (SLA) battery pack, 4V, 10 Ah / 5-24V external All other models: Rechargeable lithium battery / 5-24V external

Operating Temperature −40° C to +85° C (range varies by power source) (TLT model max of +65° C)

Temperature Accuracy ±0.5° C

Direct Connection Type USB

Enclosure Die-cast aluminum, IP 68 rated to 1.5 m

Dimensions Refer to the product instruction manual

Channels 4 lnput Type mV, V, mA, Ω lnput Range (individually configurable)

0-150 mV, 0-500 mV, 0-1 V, 0-5 V, 0-10 V, 0-15 V, ±150 mV, ±500 mV, ±1 V, ±5 V, ±10 V, ±15 V, ±20 mA, 0-20 mA, 4-20 mA

Voltage Mode Accuracy ±0.1% or better

Current in Mode ±0.2% or better

Resolution 16-bit

Zero Drift ±6 μV/°C

Span Drift ±25 ppm/°C (typical)

CMR @ 50/60 Hz 92 dB min.

MEMS Sensors Limits per Model

ADR: 64 sensors (90 sensors, with the sensor string powered via external 12 V power supply) DHP: 250 sensors

Communication Protocol RS-485 Modbus

Digital DATA Logger Specifications

Trueness 0.082 Hz

Frequency Precision ±0.146 Hz (99% CI)

Frequency Resolution ±0.002 Hz

VW Frequency Range 400-6,500 Hz

Vibrating Wire Specifications

Analog data logger Specifications