초록 ▼

A power line carrier communication system for monitoring refrigerated containers which includes a master monitoring unit and a first power line interface which interchange messages in a first format. The first power line interface translates the first format to a second format suitable for power lin

A power line carrier communication system for monitoring refrigerated containers which includes a master monitoring unit and a first power line interface which interchange messages in a first format. The first power line interface translates the first format to a second format suitable for power line environment, and messages in the second format are applied to a power line. Remote monitoring units receive the messages from the power line, and they return messages to the power line containing status data relative to refrigerated containers. The second format includes a message starting preamble having a duration and logic level which is not duplicated by normal operation of the apparatus, enhancing the probability of proper message synchronization and reception over noisy power line environments.

대표청구항 ▼

A power line carrier communication system for monitoring refrigerated containers, comprising: a local electrical distribution power line, a master monitoring unit, a first power line interface between said master monitoring unit, and said local electrical distribution power line, a plurality of refr

A power line carrier communication system for monitoring refrigerated containers, comprising: a local electrical distribution power line, a master monitoring unit, a first power line interface between said master monitoring unit, and said local electrical distribution power line, a plurality of refrigerated containers, and a plurality of remote monitoring units, one for each refrigerated container to be monitored by said master monitoring unit, said master monitoring unit preparing and transmitting messages to said first power line interface in a first message format, said first power line interface including means for transmitting messages to and receiving messages from said master monitoring unit, message translating means, and means for applying messages to and receiving messages from said local electrical power distribution line, said message translating means translating messages received from the master monitoring unit which are to be applied to the local electrical distribution power line into a second format, and translating messages received from the local electrical distribution power line to the first message format, each of said remote monitoring units including means for receiving said second format messages from said local electrical distribution power line, and processing means for processing said second format messages, with said processing means including means for obtaining status information from an associated refrigerated container, means for incorporating said status information into a message having the second message format, and means for applying said status message to the local electrical distribution power line. said second format including message information which includes a predetermined periodic logic level for at least one bit of every ten message bits, and a message starting preamble which includes the same logic level for at least ten consecutive bits, with this ten bit message starting logic level being different than said predetermined periodic logic level, said first message format including a field position which indicates type of assignment to be performed by the first power line interface in messages received from the master monitoring unit, and wherein the first power line interface uses said same field position to indicate assignment success or failure in messages sent to the master monitoring unit.