This conductivity transmitter/controller in a panel housing is a compact, modular device that can solve a wide range of tasks due to its flexibility, featuring three slots for retrofittable circuit boards. The main input is used for sensors measuring electrolytic conductivity, specific resistance, or TDS values. Both conductive two-electrode and four-electrode measuring cells can be connected. The second analog input (compensation input) is designed for resistance thermometers Pt100 or Pt1000, NTC/PTC, or standard signals of 0(4) to 20 mA or 0 to 10 V. The two binary inputs can be used both as initiators for actions (such as HOLD, keyboard lock) and when connecting pulse generators (such as paddle wheel sensors) for flow measurement. The high-contrast graphic display allows for the representation of input signals in digits or as a bar graph. The display of parameters in plain text makes operation easy to understand and secure. The device can be programmed as a two-point, three-point, three-point step controller, or as a continuous controller. All controller outputs can be configured for P-, PI-, PD-, or PID behavior using a convenient setup program. The controller software also includes a parameter set switching and a math module. In addition to the standard inputs and outputs already described, the device also features an analog output. The power supply is provided via a switching power supply AC 110 to 240 V +10/-15% 48 to 63 Hz. The electrical connection is made at the rear via screw terminals.