SIST EN 2591-611:2004

Overview

SIST EN 2591-611:2004 is a European standard developed by the European Committee for Standardization (CEN) under the Aerospace series, focusing on test methods for optical elements. Specifically, it defines a standardized procedure to evaluate the effectiveness of cable attachment in optical connection elements under cable torsion. This standard is critical for ensuring the mechanical reliability and optical performance of fiber optic cable assemblies used in aerospace applications. It is designed to be used alongside EN 2591-100, which covers general test methods for electrical and optical connections.

Key Topics

• Scope and Purpose
  SIST EN 2591-611:2004 specifies a torsion test method for verifying the robustness of cable attachments in optical connectors, including permanent joints and fiber optic couplers. The standard addresses mechanical stress applied by cable twisting to simulate real-world operational environments.

• Test Procedure

  • The cable or cable bundle is rotated cyclically: 90° in one direction, then 180° in the opposite direction, and finally back 90° to the start position, defining one cycle.
  • The test requires 100 cycles to be performed at a rate of 25 to 35 cycles per minute.
  • The free length of cable (dimension L) for the test is specified as 15 times the cable diameter, with a maximum length of 100 mm.
  • During testing, the variation of attenuation is continuously monitored in accordance with EN 2591-602 to detect optical signal degradation caused by torsional stress.

• Specimen Preparation and Conditions
  All specimens must be fitted with normal accessories and terminated per product standards. They must be stabilized under standard test conditions for 24 hours prior to testing, ensuring consistent baseline measurements.

• Test Measurements and Acceptance Criteria
  Following the torsion cycles, specimens undergo:

  • Visual examination according to EN 2591-6101 to detect mechanical damage.
  • Insertion loss measurements as per EN 2591-601 to evaluate optical performance.
    The maximum permissible variation in attenuation and insertion loss values must comply with product-specific technical specifications.

• Sampling Requirements
  The number of contacts to be tested depends on the total number of contacts in the optical connection element, with a minimum percentage required to ensure statistical validity.

Applications

SIST EN 2591-611:2004 is essential for aerospace manufacturers and suppliers involved in the design, testing, and certification of fiber optic connections used in aircraft and spacecraft systems. The standard helps:

• Ensure mechanical integrity of fiber optic cable attachments against torsional stresses encountered during assembly, maintenance, and operation.
• Maintain optical signal quality by preventing performance degradation caused by cable twisting.
• Provide a reliable benchmark for quality control and acceptance criteria for optical cable assemblies in aerospace electrical and data communication systems.
• Support standardized testing protocols that facilitate interoperability and compliance across the aerospace industry.

Related Standards

• EN 2591-100: Aerospace series - General test methods for electrical and optical connection elements (provides overarching testing framework).
• EN 2591-601: Optical elements - Insertion loss measurement methods.
• EN 2591-602: Optical elements - Test methods evaluating variation of attenuation and optical discontinuity.
• EN 2591-6101: Visual examination procedures for optical elements after mechanical testing.

Together, these standards form a comprehensive testing suite to assess mechanical and optical performance of aerospace-grade electrical and optical connectors under various stress conditions.

Keywords: EN 2591-611, aerospace optical connectors, cable torsion test, fiber optic cable attachment, insertion loss, aerospace standards, optical connection elements, cable twisting test, optical element testing, CEN aerospace standards.