We present the results of simulation in MATLAB/Simulink and on the real-time test bed of a digital control system for a plasma unstable vertical position by the example of the T-15MD tokamak. Feedback “Plant Model–Controller” is implemented using two computers of the test bed. In real-time computers, there are DAC and ADC devices for communication with an object along with their drivers. On one side of these devices, there are digital signals (inside computers), and on the other side (outside computers), there are analog signals that characterize the operation of a closed control system. The unstable plasma model in the tokamak control system is similar to the plasma models used to develop and tune the vertical plasma position control systems in the Globus-M/M2 tokamak (Ioffe Physical-Technical Institute, St. Petersburg) and the T-11M tokamak (JSC SSC RF TRINITI, Troitsk). A voltage inverter relay model is used as an actuator, which puts the control system into a stable auto-oscillatory operating mode in the presence of negative feedback. The coil of the horizontal control field (HFC) in T-15MD is located between the chamber and toroidal field winding (TFW). The digital controller is characterized by robust properties and can be additionally configured during the control system operation. The system has been tested by two types of external actions: additive disturbance with imitation of a minor disruption of 400 A and a control set point of 0.1 m. The sampling time is set to 100 μs.