Method of logging data in a transport refrigeration unit

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, comprising the steps of:

• monitoring a plurality of predetermined variables of the transport refrigeration unit to provide data,
• 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,
• 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,
• storing data from the selected variables in the second data segment, during each trip of the transport refrigeration unit,
• said step of storing data including the step of starting the data stored in the second data segment at the address of the second data segment pointed to by the address pointer in the first data segment which is associated with the current trip of the transport refrigeration unit,
• and downloading data stored in the non-volatile memory means to a predetermined device,
• said downloading step including the step of using at least one address pointer stored in the first data segment to download associated data stored in the second data segment.