Fault Tolerant Backplane Slot Assignment

An industrial control system configured to assign addresses to a plurality of slots, the industrial control system comprising:

• a master base including a first backplane and a second backplane;
• a first master backplane switch mounted to the master base and configured to communicate on the first backplane;
• a second master backplane switch mounted to the master base and configured to communicate on the second backplane;
• a first master module mounted in a first slot on the master base, the first master module in communication with the first master backplane switch and with the second master backplane switch;
• a second master module mounted in a second slot on the master base, the second master module in communication with the first master backplane switch and with the second master backplane switch;
• at least one additional base including a first backplane and a second backplane, wherein the first backplane in the at least one additional base is configured to communicate with the first backplane in the master base and the second backplane in the at least one additional base is configured to communicate with the second backplane in the master base;
• at least one additional first backplane switch, each of the at least one additional first backplane switches is mounted to one of the at least one additional bases and is configured to communicate on the first backplane of the corresponding additional base;
• at least one additional second backplane switch, each of the at least one additional second backplane switches is mounted to one of the at least one additional bases and is configured to communicate on the second backplane of the corresponding additional base;
• and
• a plurality of additional modules, each of the plurality of additional modules is mounted in a slot on one of the at least one additional bases, wherein:
• each of the plurality of additional modules is in communication with the additional first backplane switch and the additional second backplane switch on the corresponding additional base,
• the first master backplane switch and the at least one additional first backplane switch connected one hop apart are configured to authenticate a connection between the first master backplane switch and the at least one additional first backplane switch,
• the second master backplane switch and the at least one additional second backplane switch connected one hop apart are configured to authenticate a connection between the second master backplane switch and the at least one additional second backplane switch,
• the first master backplane switch transmits a base address and a slot start address to the at least one additional first backplane switch connected one hop apart, and
• the second master backplane switch transmits the base address and the slot start address to the at least one additional second backplane switch connected one hop apart.

A method for assigning addresses to a plurality of modules in a fault tolerant industrial control system, the method comprising the steps of:

• authenticating a connection on at least one backplane between a first base and at least one additional base;
• assigning a master base address to the first base when the at least one backplane switch on the first base detects a signal indicating the first base is a master base;
• receiving a base address request at the at least one backplane switch on the first base from the at least one backplane switch on the at least one additional base;
• transmitting a base address and a slot start address from the at least one backplane switch on the first base to the at least one backplane switch on the at least one additional base responsive to receiving the base address request when the master base address has been assigned to the first base;
• receiving a slot address request from at least one module on the at least one additional base with at least one master module on the master base;
• and
• transmitting a slot address response to the at least one module on the at least one additional base from the at least one master module.