ADLINK PCI-8258 - Manual (Page 88)

74 Motion Control Theory
Figure 4-3: Control cycle
The motion program is executed in motion control cycle to control
jobs to be executed in each motion control cycle directly for more
precise completion of realtime jobs. Please pay attention to DSP
loading when doing this.
Loading of CPU in controller is hard to predict as the controller is
affected by many factors, e.g. external signals, user operations,
and algorithm process during its operations. In most cases, please
try to keep CPU utilization rate to below 70% and reserve 30% of
CPU capacity to the processing of system jobs and momentary
work loads.
Overloading (work loads exceed control cycle) may lead to
unpredictable results. This controller provides you with some
functions and tools to monitor processor utilization rate and adjust
control procedures. In case of any processor overloading, the
controller logs and warns (interrupt, please refer to section of
interrupt) that you may take for proper responses in your program.
How to use API:
get_motion_control_timing () // get usage amount of current motion
control cycle
get_max_ motion_control_timing ()// get maximum usage amount
of motion control cycle
get_motion_control_timing () // get usage amount of current host
control cycle
get_motion_control_timing () // get maximum usage amount of host
control cycle
reset_max_motion_control_timing()
reset_max_host_control_timing()
get_over_cycle_event()
get_over_cycle_count()
reset_over_cycle_count ()
Motion
control cycle
Host Control Cycle
Time
XXXX
XXXX