What is the difference between a master and a slave? How do I know if I need a slave or a master protocol?
In a typical automation system, it is the control center that initiates data acquisition and device control. The control center is thus considered to be the master system. Since the substation device responds to data acquisition and control requests, it is considered to be the slave system. The SMP Gateway contains both master and slave protocol components. The master protocol components perform as control centers and retrieve information from devices. Slave protocol components perform as devices and send information to control centers in reply to polling requests. Master protocols are thus used to get information from the IED while the slave protocols are used to accept connections from the control center.