General Information on the SINUMERIK 840Di sl
1.1 Overview of SINUMERIK 840Di sl
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
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1.1.5
Real-time properties
Windows XP is not an operating system designed for hard real-time requirements. Hard real-
time requirements mean the operating system will respond to an external event within a
defined time frame of a few µ seconds.
The NC system software is therefore integrated into Windows XP as a "Kernel mode driver".
This means it has its own integrated real-time system that runs concurrently with Windows
XP to ensure the conditions for real-time processing are met.
Real-time violations
Real-time violations occur when unsuitable PC components block interrupt processing for
too long, stopping the NC system software from being activated at the specified time.
Inappropriate PC components are drivers or hardware extensions that have an adverse
effect on the real-time behavior due to overly long interrupt disable times or PCI bus disables
in PCI bus mastering.
With real-time violations exceeding 200 µs, we cannot guarantee that the NC system
software will operate correctly. The system will respond appropriately for the magnitude of
the real-time violation:
●
Display of an error message
●
Alarm with axis stop from the NC
●
Alarm and drive-independent stopping of the axes
The real-time response can be monitored in the NCK latency displays in the system
diagnostics of the 840Di Startup (see Section "840Di Startup" (Page 38)) or the NC/PLC
diagnostics of HMI Advanced (see Section "NC/PLC Diagnostics").
Screen resolution and depth of color
The following points must be taken into account for screen resolution and depth of color
settings on the PCU.
●
Screen resolution
The standard screen resolution setting depends on the optimized value that was set for
the operator panel. This value was defined for technical reasons and should be adhered
to.
●
Color depth
The default color depth setting is 65536 colors. Higher values can, in certain
circumstances, increase the CPU time used by Windows XP and occasionally also by the
real-time operating system.
Testing or switchover
If it is necessary to test the screen resolution or switch to a different resolution and/or color
depth, the NCK must be terminated first. Otherwise a malfunction may occur in the real-time
response.
