Patent ID: 7146912
Filing Date: 2006-12-12
Classification: F42C,F42D

Abstract:
1. A method for calibrating delay time in connection with firing an electronic detonator included in an electronic detonator system, in which an internal clock frequency in the electronic detonator is used when effecting the delay time and is calibrated in relation to an external clock frequency of a control unit, comprising in the electronic detonator the steps of: extracting information about the external clock frequency from a digital data packet which is sent by the control unit to the electronic detonator, comparing the external clock frequency which is extracted from the digital data packet with the internal clock frequency of the electronic detonator in order to obtain a ratio of the external clock frequency to the internal clock frequency, using said ratio for calibration of the internal clock, and setting a first flag in the electronic detonator after completed calibration, the flag indicating that at least one calibration has been carried out and the flag being readable from the control unit by means of a digital data packet comprising a question regarding the state of said flag.