In this paper, the use of wireless sensor networks for networked control loop is analyzed. As the non beacon-enabled mode of IEEE 802.15.4/ZigBee does not ensure the stability for the control loop since non mechanism can prevent the perturbation coming from other applications sharing the same network, the quality of control has to be guaranteed for the control loop. Several possible solutions are investigated. The first one is the CSMA/CA with probabilistic priority by adjusting the minimum waiting time. The second one consists on a deterministic priority black burst mechanism in IEEE 802.15.4/ZigBee. The third one is the beacon-enabled mode using the Guaranteed Time Slot (GTS) mechanism.