A method (1000) of maintaining a fluid delivery logbook on a dispensing unit of a fluid delivery device, comprising: generating (1002), at a beginning of a current communication cycle, a dispensing unit status message； adding (1006) unacknowledged logbook entries to the dispensing unit status message if a logbook comprises entries that have not been acknowledged by a command means paired to the dispensing unit； sending (1010) the dispensing unit status message to the command means； recording (1014) receipt of the logbook entries in the dispensing unit status message if an acknowledgment message is received from the command means； and waiting (1016) for a next communication cycle.
