The compatible Robotis Controllers include a number of analog ports where you can connect any Analog Sensor operating in the 0-5V range.
With this Robotis cable you can connect extra sensors to your Robotis controllers.

Robotis provides a few types of sensors and users can also add their own custom sensor. (any analog sensor in working in the 0-5V range can be used with the Robots and queried in Roboplus Task programs).
For more information on adding custom sensors (pinout, technical information and samples), please see the Robotis Support Page.