This study discusses a Time-Division Multiple Access (TDMA)-based multiple machine control system using power line communication (PLC). Because of the non-stationary features of the PLC channel, each TDMA slot has a different error rate. The variation of the slot quality causes the variation and degradation of the control performance of each machine. This manuscript thus proposes a new transmission scheme for control information based on the cyclostationary features of the PLC channels. The results of performance evaluation show that the proposed method mitigates the performance variation of each machine and improves the overall stability and accuracy.