Characteristic values of redundant automation systems
A.1 Basic concepts
S7-400H
436
System Manual, 03/2012, A5E00267695-11
Mean Down Time (MDT)
The MDT of a system is determined by the times outlined below:
●
Time required to detect an error
●
Time required to find the cause of an error
●
Time required for troubleshooting and to restart the system
The system MDT is calculated based on the MDT of the individual system components. The
structure in which the components make up the system also forms part of the calculation.
Correlation between MDT and MTBF: MDT << MTBF
The MDT value is of the highest significance for the quality of system maintenance. The
most important factors are:
●
Qualified personnel
●
Efficient logistics
●
High-performance tools for diagnostics and error recognition
●
A sound repair strategy
The figure below shows the dependency of the MDT on the times and factors mentioned
above.
0'7
'HWHFWHUURU
)LQGFDXVH
7URXEOHVKRRWLQJ
6WDUWLQJWKHV\VWHP
4XDOLILHGSHUVRQQHO
5HSDLUVWUDWHJ\
'LDJQRVWLFV
/RJLVWLFV
Figure A-1
MDT
Содержание SIMATIC S7-400H
Страница 24: ...Preface 1 1 Preface S7 400H 24 System Manual 03 2012 A5E00267695 11 ...
Страница 46: ...Getting Started 4 5 Special layout features of SIMATIC Manager S7 400H 46 System Manual 03 2012 A5E00267695 11 ...
Страница 120: ...Memory concept 10 1 Overview of the memory concept of S7 400H CPUs S7 400H 120 System Manual 03 2012 A5E00267695 11 ...
Страница 258: ...Communication 14 8 General issues regarding communication S7 400H 258 System Manual 03 2012 A5E00267695 11 ...
Страница 354: ...Synchronization modules 18 3 Selecting fiber optic cables S7 400H 354 System Manual 03 2012 A5E00267695 11 ...
Страница 434: ...Technical data 20 6 Runtimes of the FCs and FBs for redundant I Os S7 400H 434 System Manual 03 2012 A5E00267695 11 ...
Страница 460: ...Function modules and communication processors supported by the S7 400H S7 400H 460 System Manual 03 2012 A5E00267695 11 ...