CS231-L SDI-12 Temperature Profiler
Rugged, digital temperature measurements
weather applications supported water applications supported energy applications supported gas flux and turbulence applications supported infrastructure applications supported soil applications supported


The CS231 offers the same precise temperature profiling as our CS230 SDI-12 Temperature Profiler, but with a slimmer design for easier use in borehole and road applications. The CS231 requires a smaller installation hole when compared to the CS230. For road applications, this means easier drilling, as well as less time and material to backfill.

The CS231 SDI-12 Temperature Profiler uses SDI-12 digital technology for simple integration. SDI-12 does away with analog measurement inaccuracies and susceptibility to electrical noise. The CS231 consists of a rigid probe assembly and up to four optional external temperature probes. The rigid probe assembly maintains the precise position of the temperature points within the profile, while protecting the temperature sensors in all mediums for the long term.

The CS231 is suited for a wide variety of applications and environments. The completely sealed probe assembly and external probes permit the CS231 to be used in roadbeds, soils, and water (snow and ice). 

Applications where the CS231 is used include spring load adjustment, frost and permafrost monitoring, soil, and water or snowpack temperature profiling.

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Benefits and Features

  • Lifetime min/max temperature recording
  • User-resettable min/max temperature recording
  • Automatic one-second temperature update


Technical Description

When power is supplied to the CS231 probe, the internal electronics continuously measure the temperature at an approximate rate of one measurement per second. Every output measurement obtained from the sensor is a running average of 10 consecutive one-second readings. The accuracy specification is based on an average of 10 consecutive readings. For this reason, after the initial power up, it is recommended to delay 10 seconds to obtain the best accuracy.

Because the sensor is obtaining a measurement every one second, it is recommended to use the Continuous measurement command to obtain the temperature readings. Using the “R” commands will reduce the time taken to obtain a reading with the SDI-12 protocol.


Operating Temperature Range -55° to +85°C
Typical Accuracy ±0.2°C (at -40° to +85°C)
Worst Case Accuracy
  • ±0.4°C (at -40° to +85°C)
  • ±0.5°C (at -55° to -40°C)
Resolution 0.0078°C
Communications SDI-12
Supply Voltage 9 to 28 Vdc
Warm-up Time on Power up 10 s
Maximum Sensors per Probe 32
Optional External Probes 4 maximum
Cable Insulation Polypropylene Pro-Fax 8623, 105°C
Minimum Spacing 5 cm (1.97 in.)
Maximum Length 3.0 m (118 in.)
Probe Diameter 2.13 cm (0.84 in.)
Maximum Cable Length 152 m (500 ft)
Standard External Probe Length 45 cm (18 in.)
Electronics Sealing Classification IP68

Current Consumption

Quiescent Current Drain 1.0 mA (maximum per sensor)
Active Current Drain 20 mA + (number of sensors * 1.0 mA )


Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.


Product Compatible Note
CR1000 (retired)
CR800 (retired)
CR850 (retired)

Additional Compatibility Information


Our handy CS231 Configuration Tool can help you configure your profiler, and it assists our staff with customizing your profiler to your specifications. It includes parameters for lead length, first sensor from ground, and distance between sensors.

CS231 Configurator Tool


CS230/CS231 Program Examples (4 KB) 26-08-2021

Three example programs that measure the temperature sensors on the CS230/CS231 probe. The number of temperature sensors and the SDI-12 control terminal are entered as constants at the beginning of the programs to allow users to easily change them to match their application. The example programs support the CR6 and CR1000X data loggers. Programs for other dataloggers will be similar.

The cs231.CRB program measures 15 sensors with SDI-12 addresses 1 through 9 and A through F. Every 60 s, the aR0! command polls each temperature sensor, then the data is stored in a table. Other common station data is measured every 60 seconds and stored to a daily data table.

The cs231-slow.CRB program measures 20 temperature sensors with SDI-12 addresses 1 through 9 and A through F. The program uses the SlowSequence instruction and the aR0! command to poll each temperature sensor every 60 seconds. The temperature sensor data is stored to a data table on the same interval. Other common station data is measured every 5 seconds and stored to daily and hourly data tables.

The cs231-metdata.CRB program measures 15 sensors with SDI-12 addresses 1 through 9 and A through F. Each temperature sensor is polled on power up and daily with the aR1! command to determine metadata, which is stored in a daily data table. Other common station data is measured every 60 seconds and stored to a separate daily data table.

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