The JUMO dTRON 300 series of controllers includes four freely programmable devices in different DIN formats for controlling temperature, pressure and other process variables. The high-contrast, multicolor LC display for process value, setpoint and operator prompting contains two four-digit 7-segment displays, one two-character 16-segment display, display of the active setpoints, six switch position indicators, and displays for the dimensional unit, ramp function and manual operation. Simple operation through 4 keys. The instruments can be used as 2-state, 3-state, modulating or continuous controllers. The controller software includes a program or ramp function, parameter set changeover, two autotuning (self-optimization) procedures, a math and logic module, as well as 4 limit comparators. Linearizations for the usual transducers are stored, and a customer-specific linearization table can be programmed. A setup program is available for user-friendly configuration from a PC. A serial interface for RS422/485 or Profibus-DP can be used to integrate the instruments into a data network. The electrical connection is made at the back, via screw terminals. The possible input and output configurations are shown in the following block diagram. The option boards are universally applicable for all instruments in the series.