Rockwell Automation 1747-PCINT API Software for 1746 I/O - Manual (Page 129)

OC_SetupPowerFail Action Library of Routines 6–75
Publication 1747-6.5.3 June 1998
OC_SetupPowerFail
Action OC_SetupPowerFailAction registers the action to be taken when a power fail
interrupt is received from the scanner.
Syntax:
int OC_SetupPowerFailAction(HANDLE handle, BYTE *bufptr, WORD offset, WORD length, void
(*callback)() );
Parameters:
Description:
You can configure the power failure action in four ways:
•
No action (default); the power failure interrupt is ignored ( bufptr is NULL; callback is NULL)
•
Copy a block of data to the host retentive data partition in dual port RAM ( bufptr points to the data
to save; callback is NULL)
•
Execute a user callback function ( bufptr is NULL; callback points to the routine to call)
•
Copy a block of data and execute a callback function ( bufptr points to the data to save; callback
points to the routine to call)
A system typically has at least 10 milliseconds, and possibly as much as 50 milliseconds or more between
the power fail interrupt and the loss of power. The duration of this interval is a function of the power supply
and system configuration, and it varies from system to system. You might need to experiment to determine
the typical value for a particular system.
Data is copied to the host retentive data partition at the rate of approximately 1K bytes per millisecond.
Declare bufptr as static if the OC_SetupPowerFail function is used other than in main( ) ; otherwise
random data will be sent to the host retentive data area.
Parameter: Description:
handle Must be a valid handle returned from OC_OpenScanner
bufptr
If bufptr is:
NULL no data is copied (default)
Not NULL at power fail length bytes of data are copied from
bufptr to the host retentive data partition starting at
offset .
offset Specifies the offset within the host retentive data partition to begin copying
length
Number of bytes to copy
If
length points beyond the end of the host retentive data partition, it is
truncated
callback
If callback is:
NULL no callback function is executed (default)
Not NULL the power fail interrupt routine calls this function after
copying the data to the host retentive data partition
(if configured)