Rockwell Automation 2711P Software Development Kit User Manual - Manual (Page 48)

Publication 2711P-UM005A-EN-P - March 2007
48 PanelView Plus CE-Specific Extensions to the WinCE API
A timer number identifies a specific timer. When requesting a timer,
the range of timer numbers is from 0 to MAX_TIMER_NUMBER. In
addition to timer numbers of this range, critical and non-critical timers
can be requested. Critical timers commit a physical resource and
provide very high resolution. Non critical timers share a physical
timer. Currently, there is 1 critical timer and MAX_TIMER_NUMBER
non-critical timers. The attribute USERTIMER_CRITICAL requests a
critical timer. Throughout this API, USERTIMER_CRITICAL must be
or’d with the timer number for a critical timer. Resolution of
non-critical timers is 1ms, accuracy +1/- 0ms. Critical timer resolution
is 50us, +50/-0 us. MAX_TIMER_NUMBER is
implementation-dependent but is guaranteed to be 15 minimum.
Configure Timer Functions
These functions permit an application to determine how many timers
are supported on the system and to claim a specific timer. Once
claimed, the timer is configured, run and eventually released.
UserTimerGetNumberOfTimers
This function gets the number of available timers on the system.
DWORD UserTimerGetNumberOfTimers (void);
Return Value:
Total number of application accessible timers available on the system.
This includes the critical and non-critical timers. The range is 0 to
MAX_TIMER_NUMBER.
Remarks:
Returns the number of timers on the system that are available to the
application. The number returned is the total for ALL applications. If
an application uses a timer, the number of timers available for another
application is one less.
Portability:
This function is specific to PanelView Plus CE or the RAC6182.