AL200 ALERT2 Encoder, Modulator, and Sensor Interface
ALERT2 Ready
Improved accuracy and performance for flood warning systems
weather applications water applications energy applications gas flux & turbulence applications infrastructure applications soil applications


The AL200 is an ALERT2 intelligent network device (IND) developed by Campbell Scientific, Inc. Portions of embedded code were developed and copyrighted by Blue Water Design LLC and are used under license. It is an encoder, modulator, and sensor interface designed for use both as a stand-alone device and as a peripheral to a Campbell Scientific datalogger or third-party Data Collection Platform (DCP). This device uses the Automated Local Evaluation Real Time Protocol version 2 (ALERT2) and can operate as both a remote ALERT2 transmitter and as an ALERT to ALERT2 concentrator and repeater. 

With integrated sensor inputs, the AL200 allows you to create a minimal ALERT2 transmitter/station, decreasing the cost of a typical flood-warning system. Combining the AL200 with a Campbell Scientific datalogger provides enhanced sensor support, user-defined logic and control, and datalogging capabilities.

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Detailed Description

Channels Available and Their Functions

  • P1: Tipping Bucket / Switch Closure Count Accumulator
  • SE1: Single-ended Analog Input, millivolt or milliamp
  • C1: Digital for limited SDI-12 or High/Low State
  • SW12: Switched power for powering sensors
  • G: Ground

ALERT2 Reporting

When used standalone, the AL200 can generate time and event driven reports for Battery, Clock Status, Tipping Bucket, Analog Input (mV or mA), Digital (SDI-12 or High/Low State).


Power Connector Two-wire, 0.15-in. pitch removable terminal (reverse polarity protected)
Power Requirements 9 to 18 Vdc
Configuration Device Configuration Utility over USB (settable modulation levels using Device Configuration Utility)
LED GPS, Serial, Radio (RS-232 and CS I/O share serial activity LED.)
CS I/O Port SDC 7, 8,10, or 11 (multiplexed with on-board sensor interface)
RS-232 Port DCE
USB Port Micro-B
Test Button Test transmit and tone
Temperature Range -40° to +60°C
Communication Rate
  • 1200 to 38.4k bps (RS-232 DTE Port)
  • 9600 to 460.8 kbps (CS I/O Port)
Current Drain
  • 1.5 mA (@ 12 Vdc when idle)
  • 40 mA (@ 12 Vdc during GPS fix)
Timekeeping Setting via GPS ±1 μs
Drift ±0.17 s/day (without GPS sync, 40°C temperature change)
Analog Input (SE1) Sensor Interface 0 to 5 Vdc (16-bit ADC; millivolt or 4 to 20 mA selectable)
Protocols Supported ALERT1 and ALERT2
Dimensions 16 x 7.7 x 2.2 cm (6.3 x 3.0 x 0.9 in.)

Radio Interface

Channels Available TX, PTT, switched battery, ground
RCFSK Modulation 100 to 1000 mV, ±50 mV


Compliance RoHS and CE
Product Standard EN 61326-1:2013
Test Standards
  • IEC 61000-4-2, Electrostatic Discharge Immunity
  • IEC 61000-4-3, Radiated RF Immunity
  • IEC 61000-4-4, Electrical Fast Transients Immunity
  • IEC 61000-4-5, Surge Immunity
  • IEC 61000-4-6, Conducted RF Immunity
  • CIPSR 11, Class B Emission


The AL200 supports ALERT1 and ALERT2 protocols.

Datalogger Considerations

CRBasic Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR5000 CR9000(X)

Standalone, Sensors Attached Directly To AL200

A standalone AL200 can measure:

  • Analog sensors with 0 to 5 V or 0 to 20 mA output
  • SDI-12 sensors
  • Float / contact switch sensors
  • CS451 and CS456 Pressure Transducers
  • CS475, CS476, and CS477 Radar Water-Level Sensors
  • CS460 Pressure Transducer
  • SR50A Sonic Ranging Sensor
  • CS11 AC Current Sensor


ALERT Configuration Tool v.1.1 (47.7 MB) 06-30-2016

A software utility used to configure the ALERT210 and AL200. 

AL200 ALERT2 OS v.03 (513 KB) 12-11-2014

Current AL200 ALERT2 operating system. Requires the Device Configuration Utility to update the operating system in the AL200.

View Update History

AL200 USB Drivers v.2.08.28 (1.64 MB) 03-05-2013

AL200 USB Drivers for the Windows operating system. 32 and 64 bit support for Windows 8, Windows 7, Windows Vista and Windows XP.

Note: Drivers should be loaded before plugging the AL200 into the computer.

Case Studies

Texas: Hurricane Harvey
In February of 2015, Campbell Scientific was awarded a bid to supply the Harris more
Texas: Transitioning to ALERT2
ALERT2 is a modern communication protocol that improves upon 40 years of tradition within more

Articles and Press Releases