Thermo King Corporation

Arthur A Anderson

Leonard C Vercellotti

Richard A Johnson

Dirk J Boomgaard

Romuald M Jurewicz

David A Christiansen

Dannis R Johnson

Laurence R Brickner

Robert G Colclaser Iii

John G Leddy

A method of logging data relative to the operation of a transport refrigeration unit, during each trip of the transport refrigeration unit, with the transport refrigeration unit including control means and non-volatile memory means. The method includes the steps of monitoring a plurality of predetermined variables of the transport refrigeration unit to provide data, and selecting those variables of the plurality of monitored variables whose data is to be logged in the memory means during a trip of the transport refrigeration unit. The method further includes the steps of dividing the non-volatile memory means into at least first and second data segments for storing data from the selected variables, storing an address pointer in the first data segment which points to an address in the second data segment, for each trip of the transport refrigeration unit, and storing data from the selected variables in the second data segment, during each trip of the transport refrigeration unit. The method also includes the step of downloading data stored in the non-volatile memory means to a predetermined device, using at least one address pointer stored in the first data segment to download associated data stored in the second data segment.

Method of logging data in a transport refrigeration unit

A method of mapping addresses of a plurality of refrigerated containers having remote monitoring units (RMUs) connected to a power line carrier based monitoring system which includes a master monitoring unit (MMU). The method adapts to the size of the expected number of containers to be mapped by any mapping command, to reduce the overall time to map either a large or small number of containers. The method includes the MMU selecting a modulo having a magnitude determined by the number of containers expected to be mapped, and the RMUs generating a random number within the range responsive to the modulo. The RMUs apply response messages to the power line, which include the addresses of the associated containers, at a time responsive to the magnitude of the random number.

Method of mapping refrigerated containers in a power line carrier based

A power line carrier communication system having a carrier current transceiver (CCT) interface with an electrical power line via a buffer which automatically provides a low output drive impedance while transmitting, and a high receiving impedance when receiving, all with solid state circuitry. The length of signal transmission by the CCT is monitored and automatically prevented from continuously loading the communication network in the event of a malfunction which causes a signal transmission to exceed normal maximum transmission time. Prevention of continuous loading of the communication circuit is accomplished without adverse affect on the CCT via a crowbar circuit connected to the buffer circuitry.

Power line carrier communication system

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.

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Irwin, PA, United States of America

Arthur A Anderson