BACnet MSTP optimal baud-rate selection using auto baud feature

A system for selecting an operating baud rate by a server or router or gateway connected to a Master-Slave Token-Passing (MS/TP) BACnet, the system comprising:

• a BACnet interface configured to couple to a BACnet so as to facilitate communications to and from a plurality of building automation components connected to the BACnet;
• a processor;
• and
• computer readable memory having instructions that, when executed by the processor, cause the system to:
• initiate selection of a first operating baud rate for communications over the MS/TP BACnet to an initial operating baud rate;
• advance, in response to the communications conducted over the MS/TP BACnet is determined to be reliable using the first operating baud rate, selection of a next operating baud rate for communications over the MS/TP BACnet;
• repeat, in response to the communications conducted over the MS/TP BACnet using the operating baud rate selected in a last iteration of the advancing step is determined to be reliable, the advancing step;
• and
• terminate selection of the operating baud rate in response to communications conducted over the MS/TP BACnet is determined to be reliable using a highest reliable baud rate, wherein terminating selection of the operating baud rate includes:
• broadcasting a frame indicating baud rate selection to a plurality of building automation components connected to the MS/TP BACnet;
• and
• sending a communication over the BACnet using the highest reliable baud rate.

A method for adapting to an operating baud rate by a building automation component connected to a Master-Slave Token-Passing (MS/TP) BACnet, the method comprising the steps of:

• initiating selection of a first operating baud rate for communications over the MS/TP BACnet to an initial operating baud rate;
• advancing, in response to invalidity of a cyclic redundancy check determined for the communications over the MS/TP BACnet using the initial operating baud rate for at least a threshold wait time, selection of a next operating baud rate for communications over the MS/TP BACnet;
• repeating, in response to invalidity of a cyclic redundancy check determined for the communications over the MS/TP BACnet using the operating baud rate selected in a last iteration of the advancing step, the advancing step;
• and
• terminating the method in response to validity of a cyclic redundancy check determined for the communications over the MS/TP BACnet using a valid operating baud rate.