Two wire daisy chain

• US 9,671,206 B2
• Filed: 10/12/2015
• Issued: 06/06/2017
• Est. Priority Date: 05/04/2010
• Status: Active Grant

• Current Assignee: Detnet South Africa (Pty) Ltd
• Original Assignee: Detnet South Africa (Pty) Ltd
• Inventors: Schlenter, Craig Charles
• Primary Examiner(s): Eldred, J. Woodrow
• Application Number:
  US14/881,101
• Publication Number:
  US 20160033247A1
• Time in Patent Office: 603 Days
• Field of Search: 102206, 102215, 102200, 1022025, 102322, 361248, 361249, 439488, 43962001, 439894
• CPC Class Codes: F42C 19/06 Electric contact parts specially adapted for use with electric fuzes switches operated by change of speed H01H35/06; switches operated by change of acceleration, e.g. shock or vibration, inertia switches H01H35/14; fluid-pressure-operated switches H01H35/24
• CPC Class Codes: F42D 1/045 Arrangements for electric ignition dynamo-electric generators H02K
• CPC Class Codes: F42D 1/05 Electric circuits for blasting
• CPC Class Codes: F42D 1/055 specially adapted for firing multiple charges with a time delay

Abstract

A detonator which, in response to a command, uses a first modulation process to generate a first signal and, in response to an event, uses a second modulation process to generate a second signal.

Claims

1. A connector for connecting a detonator to a two-wire bus, wherein the connector includes a sensor and at least a first switch which is operable in response to the sensor, wherein the sensor is capable of distinguishing a first signal received by the sensor from a second signal received by the sensor on the basis of modulation processes used in the generation of the first and second signals.

2. A connector according to claim 1 wherein the sensor causes operation of the first switch only upon detection of the second signal by the sensor.

3. A connector according to claim 2 wherein the switching action of the first switch is implemented through the use of field effect transistors.

4. A connector according to claim 1 wherein the first signal has a first current amplitude and the second signal has a second current amplitude which is higher than the first current amplitude.

5. A connector according to claim 1 wherein the second signal is at a higher level of modulation than the first signal.

6. A connector according to claim 1 which includes first and second switches which are respectively responsive to signals which have different levels of current modulation.

7. A connector according to claim 1 wherein operation of the first switch results in one of the following:

(i) one wire of the two-wire bus is open circuited and then closed, and

(ii) both wires of the two-wire bus are open circuited and then closed.