List of Type Approvals > List of Type Approved Programmable Electronic Systems (PES) (PLC's)

Recommended Features of Safety-Related Engineering Software

• Features to facilitate configuration, programming and tests
  
  - Encapsulation of program units
  - Libraries of pre-tested, application-specific function blocks
  - Standardised programming languages, e.g. as a subset of IEC 61131-3
    (Function blocks, sequential function charts, strong data type checking)
  - Cause + effect matrix programming
  - Use of Simulator
  
  
• Features to support modifications
  
  - Encapsulation of program units
  - Function blocks without global variables
  - Safety-related and non-safety-related program and parameter are secrued by individual CRC-checksums
  - Revision comparator
  - Version-Control System with individual access rights
    Configuration checker (Example: is the proposed online-modification allowed ?)