MIL-STD-1901A
5.2.3 Non-interrupted pyrotechnic train control. When the pyrotechnic train contains only those materials allowed by 5.2.1, no pyrotechnic train interruption is required. In this case, one of the following methods of firing energy train control is required:
5.2.3.1 Firing energy train interruption with low voltage devices. An example of a firing energy train, which would require interruption, is an ignition system using a low voltage (activated by less than 500 volts) laser diode, with associated optical transmission hardware and an approved in line pyrotechnic. At least one firing energy train interrupter is required if low voltage devices are used. Low voltage devices are defined as those incorporating initiators requiring less than 500 volts or less than the maximum voltage available in the ignition system (see paragraph 5.2.4.3) prior to commit to launch (whichever is greater). Interruption of the low voltage alone in these applications is not an acceptable design. The design of the firing energy train interruption shall comply with the following:
a. The interrupter shall be rendered ineffective by the arming energy and automatically return to a non-armed state upon removal of the arming energy.
b. If the first pyrotechnic element is positioned such that safety is dependent upon the presence of an interrupter, the design shall include positive means to prevent the ISD from being assembled without the properly positioned interrupter.
c. If the first pyrotechnic element is positioned such that omission of the interrupter will prohibit transfer to the pyrotechnic train, a single interrupter is acceptable.
d. The effectiveness of the interruption prior to initiation of the arming sequence shall be determined numerically and the methodology and results presented and justified to the appropriate service safety authority.
5.2.3.2 Firing energy train interruption with high voltage devices. Firing energy train interruption is not required if only initiators meeting the requirements of paragraph 5.2.4.1 are used. However, function energy shall be controlled to preclude unintentional arming and firing. At least two energy interrupters, each controlled by an independent safety feature shall prevent arming until intent to launch the munition. The
IS shall not be capable of functioning in the absence of or as a result of static failure of all of the energy interrupters. Removal of the arming signal shall automatically return the firing energy train to a non-armed state.
5.2.4 Initiator electrical sensitivity
5.2.4.1 High voltage non-interrupted pyrotechnic train. The initiator for an electrically fired non-interrupted train shall:
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