Industrial automation can benefit from applying wireless sensor and actuator networks (WSAN) on cost reduction, mobility and flexibility. However, wireless solutions are more prone to interferences compared to wired ones. In order to avoid production losses and to keep the revenues at an anticipated level, it is of utmost importance for WSANs to meet the stringent requirements from industrial automation, such as high reliability and real-time performance. A great number of research efforts were taken in this field based on simulations, but simulation results may not show sufficient confidence. Existing implementations and products compatible with the standards may still fail to provide reliable and real-time communication. Therefore, in this paper we built a prototype of industrial wireless sensor and actuator networks (IWSAN) and implemented a protocol stack, aiming for providing reliable and real-time communication for mission-critical industrial applications. Afterwards, we deployed our prototype and conducted measurements in real industrial environments. Our measurement results exhibited possibility of applying IWSANs for industrial applications and brought more evidence to our industry.