Installation manual
HB-37420-810-01-25F-EN SMX100 Installation manual.docx
Page 245 of 260
Version: 25F
12.3.5 Hard and Software design
The performance targets from the hardware and software specification are implemented in
the actual system design.
The performance targets for the components to be used and their wiring from the hardware
specification must also be met, the same applies for the performance targets for fault
exclusions. Both must be achieved and documented with appropriate means.
In the software one must also account for and completely implement the targets from the
software specification.
Furthermore one must consider the superimposed targets placed on the software by safety
related programming. These are among others:
Modular and clear program structure
Assignment of functions to the safety functions
Understandable representation functions by:
Unambiguous designations
Understandable comments
Use of tested functions / function modules, as far as this is possible
Defensive programming
12.3.6 Testing of the hardware design
After completing the planning the hardware design must be examined for compliance with
the targets from the hardware specification.
Furthermore, one must check the compliance with the specified safety level for each safety
function by using suitable analyses. The analysis methods have been described in applicable
standards (e.g. EN ISO 13849-1).
Analysis of wiring diagram
Compliance with the targets set under safety related aspects can be checked by means of
the wiring diagram and the bill of materials. The following must be checked in particular:
the correct wiring of components as specified,
the dual-channel structure, as far as specified
the non-reactivity of parallel, redundant channels.
The use of components as specified
The checks should be made by understandable analysis.
12.3.6.1
Iterative testing of the achieved safety level
The achieved safety level must be determined by means of the circuit structure
(= architecture single-channel ( dual-channel / with or without diagnose), the characteristic
device data (manufacturer's data or appropriate sources) and the diagnostic coverage
(manufacturer's data PES or general sources). Appropriate measures can be taken from the
underlying safety standard.
