SDI-12 console

You will use the SDI-12 console to configure connected sensors with an SDI-12 interface, such as the Stevens HydraProbe. This may include setting the address for the sensor or configuring the variables. Here we use commands for a Stevens HydraProbe. You can connect and configure nearly any SDI-12 sensor, but you will need to refer to the documentation of that sensor for details on configuring it.

To use the SDI-12 console to configure a sensor, you must be connected to the LI-8250 Multiplexer user interface, the sensor must be connected to a port on an 8200-104/C Long-Term Chamber, and that chamber must be connected to a port on the multiplexer or an extension manifold. You can connect multiple sensors to a port on a LI-COR long-term chamber using the sensor T-split fitting (part number 310-18516).

Note: It is advised to connect and configure the sensors on each chamber one at a time. Often, but not always, the default address of a sensor is 0. If multiple sensors on the same chamber have the same address, communication with either sensor will not be possible. Related to this, the console does allow you to change the address of one sensor to the address of another. If more than one sensor is assigned the same address, you will need to disconnect all but one of the sensors and change the addresses.

To open the SDI-12 console, first connect to the LI-8250 Multiplexer user interface. Then expand the Tools drop-down and click SDI-12 Console.

You will then need to change the active port. The active port will need to be the same multiplexer port number or multiplexer/extension manifold port number combination that the chamber with the sensor is on. For example, if you would like to configure a Stevens HydraProbe connected to a chamber on an 8250-01 Extension Manifold, you will:

  1. Determine which port of the LI-8250 Multiplexer the 8250-01 Extension Manifold is on.
  2. In this case, it's port 2.
  3. Determine which port of the 8250-01 Extension Manifold the chamber with the sensor is on.
  4. In this case, it's port 1.
  5. Change the active port to 2-1.

To change the active port, expand the Active Port drop-down and click the port number to make it the active port. Remember to change the active port before attempting to configure a sensor on a different chamber.

Anatomy of a command

The first character in a command is the sensor address. Whenever you would like to communicate with a sensor, your command will begin with the address of that sensor. In the example in this section, we change the address from 0 to 1, but the address could be any number from 0 to 9. While the full SDI-12 protocol does allow for a wider range of addresses, the LI-8250 Multiplexer uses a partial implementation and can only accept numeric addresses.

Note: Typically, device specific SDI-12 commands are followed by an exclamation mark (!). In the SDI-12 Console, you do not need to add the exclamation mark as it is added automatically.

Command Definition
The command 0A1 changes the address for sensor 0 to 1.
The command 1XW_SOIL_G changes a setting on the sensor. In a Stevens HydraProbe, 1XW_SOIL_G changes the soil type for sensor 1 to general (see Table 6‑1).
(Version 3 and older) The command 1XM=0 changes the measurement for sensor 1 to the first default set.

Configuring a Stevens HydraProbe

Here we provide a basic overview of how to configure a Stevens HydraProbe. Some of the commands, such as changing the address, may be similar for other sensors. Refer to the documentation of that sensor for details.

Note: We recommend that you keep the Stevens HydraProbe in its default configuration for everything except the address and soil type.

With the first sensor you would like to configure connected and the active port set, click Query All at the bottom of the page. A query will search the active port for any connected devices. Devices that are found will report back the model number, serial number, and address of the sensor.

Changing the address

The first thing you will want to do with any sensor is to change its address. The address is used to communicate with the sensor. Choose a number between 0 and 9 unique for that chamber. For example, each chamber may have a sensor with an address of 1, but having more than one sensor on the same chamber with the same address will disable communication with any sensor using that address on that chamber. If you will be using more than one sensor, it is not recommended that you use 0 as many sensors use that as the default address.

To change the address from 0 to 1, enter the command 0A1, then click Send or press Enter. This command tells the sensor with the address 0 to set the address (A) to 1. You should receive a response of 1 as confirmation from the sensor that the address was changed.

Changing the soil type

The Stevens HydraProbe offers support for various types of soil, and you should change the soil type to reflect the type of soil representative of your site. This updates the calibration coefficient the probe uses to convert signal to soil moisture/temperature/electrical conductivity values. The different soil types and their corresponding commands can be found inTable 6‑1 and Table 6‑2

To change the soil type for sensor 1 to silt, enter the command 1XS2, then Send. This command tells the sensor with the address 1 to set the soil type (XS) to silt (2). Choose the soil type that best represents the soil at your site.

Table 6‑1. Stevens HydraProbe (v4 and newer) soil type commands.
Command Which means...
1XW_SOIL_G Sensor 1 soil type is now general
1XW_SOIL_O Sensor 1 soil type is now organic
1XW_SOIL_R Sensor 1 soil type is now rockwool
Table 6‑2. Stevens HydraProbe (v3) soil type commands and definitions.
Command Sensor returns... Which means...
1XS1 1S1=SAND Sensor 1 soil type is now 1 or sand
1XS2 1S2=SILT Sensor 1 soil type is now 2 or silt
1XS3 1S3=CLAY Sensor 1 soil type is now 3 or clay
1XS4 1S4=LOAM Sensor 1 soil type is now 4 or loam