Rockwell Automation 1747-PCIS API Software - Open Controller - Manual (Page 71)

Publication 1747-UM002A-US-P - June 2000
Library of Routines 6-11
Parameters:
Description:
There are three types of end-of-scan messages:
End-of-scan messages are generated from the scanner to the API via
interrupts after each scan. The scan rate is controlled by the
OC_SetScanTime function and end-of-scan interrupts are generated at
the scan rate. Enabling end-of-scan messages can affect the
performance of the application due to the overhead incurred in
processing these interrupts. An alternative method to synchronize with
the scanner’s I/O scan is to monitor the scanner watchdog register,
which is incremented at the end of each timed I/O scan. See
OC_GetScannerWatchdogCount.
Return Value:
Considerations:
Supported in the DOS API library and the Windows NT API library
Parameter: Description:
handle Must be a valid handle returned from OC_OpenScanner
mode If mode is:
EOSMSG_ENABLE the scanner generates an end-of-scan
message after each scan. Use the
OC_PollScanner function to retrieve
end-of-scan messages.
EOSMSG_DISABLE the scanner does not generate End-of-scan
messages. End-of-scan messages are
disabled after the scanner has been reset.
This type of message: Is generated after:
OCMSG_EOS_DMDIN a OC_DemandInputScan command has
completed
OCMSG_EOS_DMDOUT a OC_DemandOutputScan command has
completed
OCMSG_EOS each timed I/O scan
Name: Value: Description:
SUCCESS 0 notification was generated successfully
ERR_OCACCESS 2 handle does not have access to scanner
ERR_OCINIT 5 scanner has not been initialized, see OC_InitScanner
ERR_OCPARAM 8 parameter contains invalid value