Firing-readiness capacitance check of a pyrotechnic device such as an electronic detonator

Abstract

Firing-readiness diagnostics in an electronic pyrotechnic device such as an electronic detonator or an electronic blasting system thereof. The diagnostics may include a check for any incompatible attached devices, a resistance or continuity check of an ignition element, and/or a capacitance check of a firing capacitor.

1 . An electronic detonator for use in mining or blasting and having firing-readiness diagnostics, comprising an igniter that includes a firing capacitor, and electronic circuitry configured and/or programmed to check the capacitance of the firing capacitor against one or more capacitance limits.  
   
   
       2 . The electronic detonator of  claim 1 , wherein said one or more capacitance limits includes a lower capacitance limit.  
   
   
       3 . The electronic detonator of  claim 1 , wherein said one or more capacitance limits includes an upper capacitance limit.  
   
   
       4 . The electronic detonator of  claim 1 , wherein said electronic circuitry is configured and/or programmed to check that the firing capacitor has a capacitance that is above a lower capacitance limit and below an upper capacitance limit.  
   
   
       5 . The electronic detonator of  claim 2 , wherein said electronic detonator is configured and/or programmed to charge said firing capacitor using a controlled charging process, and said electronic circuitry is configured and/or programmed to check that the duration of controlled charging of said firing capacitor exceeds a minimum time limit that corresponds to said lower capacitance limit.  
   
   
       6 . The electronic detonator of  claim 3 , wherein said electronic detonator is configured and/or programmed to charge said firing capacitor using a controlled charging process, and said electronic circuitry is configured and/or programmed to check that the duration of controlled charging of said firing capacitor does not exceed a maximum time limit that corresponds to said upper capacitance limit.  
   
   
       7 . The electronic detonator of  claim 4 , wherein said electronic detonator is configured and/or programmed to charge said firing capacitor using a controlled charging process, and said electronic circuitry is configured and/or programmed to check that the duration of controlled charging of said firing capacitor exceeds a minimum time limit that corresponds to said lower capacitance limit but does not exceed a maximum time limit that corresponds to said upper capacitance limit.  
   
   
       8 . The electronic detonator of  claim 5 , wherein said controlled charging process is a constant-current, rail-voltage limited process.  
   
   
       9 . The electronic detonator of  claim 6 , wherein said controlled charging process is a constant-current, rail-voltage limited process.  
   
   
       10 . The electronic detonator of  claim 7 , wherein said controlled charging process is a constant-current, rail-voltage limited process.  
   
   
       11 . The electronic detonator of  claim 10 , wherein said electronic detonator includes an application-specific integrated circuit that contains said electronic circuitry, and wherein said igniter is hermetically sealed and said ignition element is a bridgewire.  
   
   
       12 . An electronically connected system for use in mining or blasting comprising: 
 a) a master device;    b) a bus connected to said master device; and,    c) a plurality of electronic detonators connected to said bus, each said electronic detonator comprising an igniter that includes a firing capacitor, and electronic circuitry configured and/or programmed to check the capacitance of the firing capacitor against one or more capacitance limits.    
   
   
       13 . The electronically connected system of  claim 12 , wherein said electronic circuitry is configured and/or programmed to check that the firing capacitor has a capacitance that is above a lower capacitance limit and below an upper capacitance limit.  
   
   
       14 . The electronically connected system of  claim 13 , wherein said electronic detonator is configured and/or programmed to charge said firing capacitor using a controlled charging process, and said electronic circuitry is configured and/or programmed to check that the duration of controlled charging of said firing capacitor exceeds a minimum time limit that corresponds to said lower capacitance limit but does not exceed a maximum time limit that corresponds to said upper capacitance limit.  
   
   
       15 . The electronically connected system of  claim 14 , wherein said controlled charging process is a constant-current, rail-voltage limited process.  
   
   
       16 . A method of operating a system of electronic detonators for use in mining or blasting, comprising the following steps: 
 a) providing a master device and a bus connected to the master device;    b) connecting a plurality of electronic detonators each having a firing capacitor to said bus;    c) issuing one or more commands from said master device on said bus; and,    d) after step c), checking the capacitance of the firing capacitor against one or more capacitance limits.    
   
   
       17 . The method of  claim 16 , further comprising the step of issuing information to said master device from any electronic detonator that fails said capacitance check.  
   
   
       18 . The method of  claim 16 , wherein step d) includes checking that the firing capacitor has a capacitance that is above a lower capacitance limit and below an upper capacitance limit.  
   
   
       19 . The method of  claim 18 , further including the step of charging said firing capacitor using a controlled charging process, wherein step d) includes checking that the duration of controlled charging of said firing capacitor exceeds a minimum time limit that corresponds to said lower capacitance limit but does not exceed a maximum time limit that corresponds to said upper capacitance limit.  
   
   
       20 . The method of  claim 19 , wherein said controlled charging process is a constant current, rail-voltage limited process, and step d) is performed during said step of charging.