A communication system for an industrial process includes multiple slave modules connected in series with a master controller. The master controller stores a communication schedule that defines an ordered sequence of messages and identifiers associated with each message. The master controller transmits messages downstream through the slave modules to a terminal one of the slave modules. The terminal slave module generates a return message that is transmitted upstream to the master controller. Each slave module receives each downstream message, identifies based on the message identifier whether the message is associated with response information from the slave module, and inserts the response information into corresponding upstream messages.