There is presented PLC-PIDTuner application developed for tuning PID controller in S7 Simatic PLCs. It allows plant identification, calculation of controller parameters and verification of the control system using different quality indexes. It provides data collection from the real process and computer simulation of designed control system. Such solution allows to customize systems properties without carrying out costly experiments. Proposed application allows user to easily develop different algorithms for each stage of PID control system design. Finally, there is presented example of using developed PLC-PIDTuner platform in simulated process described by third order system with delay.