Search

US-12618656-B2 - Method of communication

US12618656B2US 12618656 B2US12618656 B2US 12618656B2US-12618656-B2

Abstract

A method of communicating in a blast system which includes the steps of transmitting timing signals from a master transceiver to a plurality of local transceivers, in response, at each local transceiver, defining a succession of micro-slots and calculating a size of a respective bin which is associated with each micro-slot, transmitting a packet from the master transceiver, at each local transceiver calculating a uniform random value, identifying the bin in which the uniform random value is located and during the micro-slot which is associated with the identified bin, if no transmission of a reply signal from any other local transceiver is detected, in response to the packet transmitting a reply signal from the local transceiver to the master transceiver.

Inventors

  • Ian William GUEST

Assignees

  • DETNET SOUTH AFRICA (PTY) LTD

Dates

Publication Date
20260505
Application Date
20230726
Priority Date
20220914

Claims (7)

  1. 1 . A method of communicating in a blast system ( 10 ) which includes a blast site ( 12 ), a blast controller ( 22 ), a master transceiver ( 24 ) which is operable under the control of the blast controller ( 22 ), and a plurality of detonator assemblies ( 20 ) which are respectively deployed at the blast site ( 12 ), each detonator assembly ( 20 ) respectively including a processor ( 36 ), a unique identifier ( 38 ) which is stored in memory associated with the processor ( 36 ), and a local transceiver ( 34 ) which is operable under the control of the processor ( 36 ), wherein the method comprises the steps of: (a) transmitting timing signals ( 50 ) from the master transceiver ( 24 ) to the local transceivers ( 34 ) thereby to define a succession of frames ( 52 ) each of a known time duration (T2−T1) and to synchronise operation of the local transceivers ( 34 ) of the plurality of detonator assemblies ( 20 ) with the operation of the master transceiver ( 24 ), (b) dividing each frame ( 52 ) into a plurality of slots ( 56 ) each of which has a respective predetermined duration (TS), each slot ( 56 ) including a respective plurality of micro-slots each of which has a respective defined duration, (c) for each slot assigning a respective value (T) to each of a number of micro-slots ( 66 ) selected from said plurality of micro-slots in the slot, (d) calculating a size (BS) of a bin (B) which is respectively associated with each selected micro-slot ( 66 ), wherein the bin size (BS) is dependent on the value (T) assigned to said selected micro-slot, (e) transmitting a packet ( 74 ) from the master transceiver ( 24 ) to one or more local transceivers ( 34 ), wherein said packet ( 74 ) includes data, information or commands which are linked to at least one local transceiver ( 34 ) whereby said local transceiver ( 34 ) is prompted to send a respective reply signal ( 90 ) to the master transceiver ( 24 ), the reply signal ( 90 ) including the unique identifier ( 38 ) of the respective detonator assembly ( 20 ), and at said local transceiver ( 34 ), (f) using a uniform random number generator ( 78 ) to calculate a uniform random value ( 76 ), (g) identifying a bin (B) in which said uniform random value ( 76 ) is located, (h) identifying the micro-slot ( 66 ) which is associated with said identified bin (B), (i) during a defined interval ( 84 ) in the duration of said identified micro-slot ( 66 ), enabling the respective local transceiver ( 34 ) to be operative to detect transmission of a reply signal from any other local transceiver, and (j) if the detection in step (i) is negative, transmitting said reply signal ( 90 ) responsive to the packet ( 74 ) from the respective local transceiver ( 34 ) to the master transceiver ( 24 ).
  2. 2 . The method of claim 1 wherein, if the detection in step (i) is positive, steps (f) to (i) are repeated.
  3. 3 . The method of claim 1 which includes at least one of the following steps: varying the number of micro-slots in each slot; and varying the number of slots per frame.
  4. 4 . The method of claim 1 wherein in step (d) the size (BS) of the respective bin for a micro-slot ( 66 ) is given by BS=k T where T is the value assigned to the micro-slot ( 66 ), and where k is dependent on the number (n) of detonator assemblies in the blast system, the duration (d) of each time period allowed for the transmission of a reply signal from a local transceiver to the master transceiver, and the desired latency ( 1 ) of the blast system.
  5. 5 . The method of claim 1 wherein, at each detonator assembly ( 20 ), during the duration of a first micro-slot the respective local transceiver ( 34 ) is placed in a reception mode for a given period ( 84 ) to implement a listen-before-talk mechanism, so as to detect transmission of a reply signal from any of the other local transceivers.
  6. 6 . The method of claim 5 wherein, if said detection is negative, the given period ( 84 ) is followed by a period ( 86 ) during which the respective local transceiver ( 34 ) is switched from the reception mode to a transmission mode, and the reply signal ( 90 ) is transmitted by the local transceiver ( 34 ) to the master transceiver ( 24 ).
  7. 7 . The method of claim 5 wherein, if said detection is positive, steps (f) to (i) are again implemented.

Description

This application is the U.S. national phase of International Application No. PCT/ZA2023/050041 filed Jul. 26, 2023, which designated the U.S. and claims priority to ZA Patent Application No. 2022/10178 filed Sep. 14, 2022, the entire contents of each of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION This invention relates to a method of communicating, using wireless techniques, in a blast system which includes a blast controller and a large number of detonator assemblies which are deployed at respective boreholes positioned at defined locations in a blast site. In this type of wireless-based blast system, each detonator assembly includes a transmitter/receiver which can be positioned on ground and which is connected via conductors to a detonator arrangement in a borehole, which is charged with explosive material. The transmitter/receiver is operative to communicate with the blast controller which is at a remote location and to initiate the detonator arrangement in response to a fire signal from the blast controller. To enhance productivity and efficiency of operation, the number of detonator assemblies which are included in the blast system and which are under the control of the blast controller can be of the order of several thousand. A signal from the blast controller can be sent via a master transceiver for various operative purposes on a broadcast basis to all the detonator assemblies. Additionally a signal, from the blast controller, which is destined for a single detonator assembly, can be distinguished through the use of an identifier, in the blast controller signal, which is uniquely associated with the targeted detonator assembly. Correct receipt by the blast controller, of a reply signal from a given detonator assembly, is confirmed by transmission of an acknowledgement signal from the master transceiver to the transmitter/receiver at the given assembly. Reply signals are transmitted to the master transceiver by the transmitter/receiver arrangements at the various detonator assemblies at defined times. It is however possible for some of these reply signals to be transmitted more or less simultaneously. This results in what is referred to as a collision. The blast controller is then unable to receive useful information, for data in a reply signal from one detonator assembly is mixed with and cannot be distinguished from data in a reply signal from another detonator assembly. To avoid or reduce the incidence of collisions the times at which the detonator assemblies can transmit their reply signals can be staggered, but this results in increased latency. When a collision is detected the detonator assemblies, from which the colliding reply signals originated, do not receive confirmatory signals from the blast controller. In this way the respective detonator assemblies are prompted to retransmit the reply signals. However if the reply signals from these assemblies are retransmitted in the next available time slot or frame they will again collide. The invention is concerned with reducing the likelihood of collisions of the aforementioned kind thereby to reduce the time taken to set up and execute a blasting sequence. SUMMARY OF THE INVENTION The invention provides a method of communicating in a blast system which includes a blast site, a blast controller, a master transceiver which is operable under the control of the blast controller, and a plurality of detonator assemblies which are respectively deployed at the blast site, each detonator assembly respectively including a processor, a unique identifier which is stored in memory associated with the processor and a local transceiver which is operable under the control of the processor, wherein the method comprises the steps of: (a) transmitting timing signals from the master transceiver to the local transceivers thereby to define a succession of frames each of a known time duration and to synchronise operation of the local transceivers of the plurality of detonator assemblies with the operation of the master transceiver,(b) dividing each frame into a plurality of slots each of which has a respective predetermined duration, each slot including a respective plurality of micro-slots each of which has a respective defined duration,(c) for each slot assigning a respective value (T) to each of a number of micro-slots selected from said plurality of micro-slots in the slot,(d) calculating a size (BS) of a bin which is respectively associated with each selected micro-slot, wherein the bin size (BS) is dependent on the value (T) assigned to said selected micro-slot,(e) transmitting a packet from the master transceiver to one or more local transceivers, wherein said packet includes data, information or commands which are linked to at least one local transceiver, whereby said local transceiver is prompted to send a respective reply signal to the master transceiver, the reply signal including the unique identifier of the respective detonator