CR206X Datalogger with 900 MHz Spread-Spectrum Radio
Smallest, Lowest-Cost Datalogger
Built-in spread-spectrum radio
weather applications water applications energy applications gas flux & turbulence applications infrastructure applications soil applications


The CR206X is a small, low-cost datalogger that includes an internal 900 MHz spread-spectrum radio for transmitting data to another CR206(X), an RF401(A) radio, or an RF430 radio. The 900 MHz frequency is used in the US and Canada.

The CR206X provides stand-alone operation in harsh, remote environments. It reads input from one or two sensors, then transmits its data wirelessly via its internal radio. Multiple CR206Xs can be configured as a network, or units can be deployed individually.

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Benefits and Features

  • Small, low-cost datalogger with internal spread spectrum radio for wireless communications
  • Integrated radio lets this datalogger function like a wireless sensor in a network, transmitting to a master datalogger
  • Ideal applications include wind energy, rural water, water level/flow, aquaculture, water quality
  • Gas Discharge Tube (GDT) protected inputs
  • Optimal for measuring one or two simple sensors
  • Makes SDI-12, single-ended analog, pulse, switch closure, and bridge measurements
  • Battery-backed clock that ensures accurate time is maintained while datalogger is disconnected from battery power
  • Program with LoggerNet, PC400, or Short Cut to fit your setup
  • PakBus, Modbus, and SDI-12 protocols supported

End-of-Life Product

For new projects, the CR300-series dataloggers are recommended instead of the CR200X-series dataloggers. The CR300-series builds on the successful features of the CR200X-series dataloggers, while adding new features. The CR200X-series dataloggers will continue to be available for customers with existing CR200X networks until 16 January 2018. Refer to the CR200X-Series Datalogger Discontinuation Notice for details.


Detailed Description

The CR206X can be used in a wireless sensor network. Wireless sensor networks are appealing because they are often more economical than trenching, laying conduit, and pulling wire. When used as a wireless sensor, the CR206X measures the sensors attached to it, then transmits its data wirelessly via its spread-spectrum radio to a master datalogger. The master datalogger must support the PakBus communication protocol (e.g., CR800, CR850, CR1000, CR3000). For more information on how to configure a PakBus system, please read our PakBus Networking Guide.

The CR206X has several input channels for measuring a variety of sensors. Gas discharge tubes provide rugged electrostatic discharge protection for the inputs.

The CR206X does not make differential measurements and is not compatible with SDM devices, multiplexers, or thermocouples (refer to the Compatibility information for compatible sensors, peripherals, and software). Recalibration services are not offered for the CR206X datalogger.


-NOTE- Note: Additional specifications are listed in the CR200X-Series Specifications Sheet.
Internal Spread-Spectrum Radio Operating Frequency Range 910 to 918 MHz
Radio Power 250 mW
Older CR206X dataloggers (serial # < 19122) have 100 mW radios.
Antenna Connector Type RPSMA female
Transmitter Power Output 250 mW
Maximum Scan Rate 1 Hz
Analog Channels
  • The single-ended analog inputs can also be used as control ports.
  • 5 single-ended (no differential) individually configured
Pulse Count Channels 2
Switched Excitation Channels 2 voltage
Digital Ports
  • Certain digital ports can be used to count switch closures.
  • 2 I/O
Communication Ports 1 RS-232
Switched Battery Port 1
Input Voltage Range 0 to 2500 mV
Analog Voltage Accuracy ±(0.25% of reading + (1.2 mV)x(offset)) at -40° to +50°C
Analog Voltage Resolution 0.6 mV
A/D Bits 12
Operating Temperature -40° to +50°C
Power Requirements 7 to 16 Vdc
Typical Current Drain
  • ~0.2 mA (quiescent)
  • ~3 mA (active, no radio)
  • ~20 mA (active, radio receive)
  • ~75 mA (active, radio transmit)
Clock Accuracy
  • 8.2 min./month (@ -40° to +50°C)
  • 1 min./month (@ +25°C)
Protocols Supported PakBus (leaf node only), SDI-12
Warranty 3 years
Dimensions 14.0 x 7.6 x 4.8 cm (5.5 x 3.0 x 1.9 in.)
Weight 271 g (9.5 oz)


Final Storage 512 kB of flash memory for approximately 125,000 data points
Operating System 106 kB of flash memory
Intermediate Storage 8 kB of SRAM for communication buffers, calculations, variables, etc.



The CR206X can communicate with a PC via direct connect, NL201 Network Link Interface, NL240 Wi-Fi Network Link, MD485 multidrop modem, and digital cellular modems. Data can be viewed on an iOS device, an Android device, CD295 DataView II Display, or a user-supplied PDA. To use an iOS or Android device, go to the Apple Store or Google Play and download our LoggerLink Mobile Apps free of charge. User-supplied PDAs require either PConnect or PConnectCE software.

The CR206X's internal spread spectrum radio can transmit data to other CR206(X) loggers, RF401A radios, RF401 radios, or RF430 radios. Certain CR206X settings must match the radio's settings for communications between the datalogger and radio to be successful. The factory default settings of these devices might not match; therefore, they may need to be reconfigured before communications can take place. Refer to the Quick Reference Guide for Setting Up RF401-to-CR206(X) Communications application note for more information.

If the CR206X is in the transparent mode, it can communicate with the retired CR205 loggers or RF400 radios.

Measurement & Control Peripherals

The CR206X is not compatible with SDM devices and multiplexers.


The CR206X can measure a variety of sensors including SDI-12 sensors and 4 to 20 mA sensors. It cannot make differential measurements and is not compatible with the freezing-rain/ice, fuel moisture/temperature, geographic position, present weather, soil heat flux, soil matric water potential, and strain sensors listed on our price lists.

The currently available sensors that the CR206X can measure are shown below:


TE525 TE525WS TE525MM TB4 TB4MM CS700 52202 SR50A

Relative Humidity

CS215 HMP60 HMP155A HC2S3 083E

Soil Volumetric Water Content

EasyAG EnviroSCAN CS616 CS625 CS650 CS655


CS300 LI200X LI190SB LP02 CMP3 CMP6 CMP11 CMP21 Radiometers


107 108 109 109SS 110PV 43347 Thermocouples

Water Level

CS410 CS451 CS456 CS460 CS470-series CS475-series

Water Quality



014A 27106T 03002 034B 05103 05103-45 05106 05305 WINDSONIC4 WINDSONIC1 CSAT3

Other Sensors

  • CS11 Current Transformer
  • CS100, CS106, and 092 barometric pressure sensors
  • 255-100 Evaporation Gauge
  • 237 and LWS leaf wetness sensors
  • WXT520 Weather Transmitter


Applications with minimal power requirements can use the ENC200 enclosure to house the datalogger and the #16869 sealed rechargeable battery. The ENC200 cannot house a barometer or a battery that is larger than the #16869. However, an ENC10/12 or ENC12/14 enclosure is adequate for most CR206X-based systems.

Power Supplies

The CR206X uses an external power supply and has a built-in regulator. When connected to the on-board charging circuit, the sealed rechargeable battery should be 7 A h or smaller. Using larger batteries with the datalogger's built-in charger may result in excessive PC board heating. This is especially a concern when the battery is deeply discharged or failing with a shorted cell. Campbell Scientific also recommends that solar panels be 10 W or less and wall chargers be 1 A or smaller.


The CR206X is compatible with the following software packages:

  • Short Cut
  • PC200W
  • PC400 (version 1.0 or higher)
  • LoggerNet (version 2.1 or higher)
  • PConnect (version 3.0 or higher)
  • PConnectCE (version 2.0 or higher)
  • VisualWeather (version 2 or higher)

Operating System Considerations

Newer dataloggers with 250 mW radios must use OS 3 or higher for their datalogger operating system.


CR200X Series OS v.04 (1.29 MB) 09-22-2015

Execution of this download installs the Operating System and Compiler on your computer for the following dataloggers:CR200X, CR206X, CR211X, CR216X and CR295X.  It also updates the support files for the CRBasic Editor.  

Note: Newer CR206X dataloggers (serial # ≥ 19122) and newer CR211X dataloggers (serial # ≥ 19143) have 250 mW radios that must use OS 3 or higher for their datalogger operating system.

View Update History

Frequently Asked Questions

Number of FAQs related to CR206X: 42

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  1. In theory, a single RF430 can communicate with 4,000 CR206X dataloggers, as this is the maximum number of unique PakBus addresses available for use in a single RF network. The practical limit depends on how frequently data is retrieved from all the remote sites.

  2. Not directly. If the CS15-L is connected to a CR200(X) datalogger, the datalogger can take the ac measurement and control a solid-state relay based on some threshold within the datalogger program. The solid-state relay can then control other relays, solenoids, or motor starters. (Use of a solid-state relay is preferred because the datalogger can trigger it with a small 5 Vdc mA signal.) For more information, see the “Measurement and Control Peripherals” section of the operator’s manual.

  3. Yes. The BMP5 Direct SDK can communicate with the datalogger as long as two conditions are met:

    1. The communications link between the datalogger and the computer is transparent.
    2. There are no excessive delays.

  4. Current dataloggers compatible with the BMP5 Direct SDK are the CR200X-series, CR1000, CR3000, CR800, and CR850.

    Retired compatible dataloggers include the CR10X-PB, CR23X-PB, and CR510-PB. These dataloggers must have the optional PakBus operating system installed, which is available on the Downloads page of our website.

  5. Yes. The simplest method is to use conditional program statements that execute most of the code based on time. For example, the data could be scheduled to log at 6 a.m. and finish at 8 p.m. using CRBasic instructions such as IfTime(). Another option is to use an IfThen/EndIf construction that does a logical test of light-level measurements based on a light sensor. An additional option is to use calculated sunrise and sunset times along with a combination of RealTime() and Case instructions.

    For more information, see the “Decisions, Decisions, Decisions…” article. 

  6. Technically, the SRM-5A is compatible with the CR200X-series dataloggers, but it is more complicated to use it with these dataloggers. To use a SRM-5A with a CR200X-series datalogger, the SRM-5A must be in the DTE position on the station modem. In addition, user-supplied adapters and gender changers are needed to complete the connections between the SRM-5A and the RS-232 port of the datalogger. Contact Campbell Scientific for more information.

  7. No. In this scenario, the base RF401A can only communicate with the RF400 devices via the transparent communications protocol, or with the CR206X dataloggers via the PakBus protocol.

  8. The CR200X-series and the retired CR200-series dataloggers are NOT compatible with SDMs or multiplexers. If more channels are needed or may be needed in the future, consider purchasing a CR800, CR850, or CR1000 instead.

  9. The maximum cable length depends on the interface being used.

    • RS-232 connections will reach 15 m (50 ft).
    • RS-485 connections go beyond 610 m (2,000 ft).
    • IP connections can be routed worldwide. 

Case Studies

New Mexico: Cavern Collapse Alarm
RESPEC, a water-resources consulting and services firm, is currently under contract to operate and more