Experimental Physics and
Industrial Control System

"J. Frederick Bartlett" <[email protected]> · Tue, 28 Sep 2004 12:09:01 -0500

  The "Record Reference Manual" states that the FLNK record field has the
following behavior:

	"This field is a database link. If FLNK is specified, processing this
record
	 will force a processing of the scan passive forward link record"

  I have an input record for which the SCAN field is set to a periodic
interval; however, I need to force processing of this record when the
corresponding output record -- both records reference the same hardware
register -- is processed. This is necessary to provide a timely update of
the input record's value so that subsequently processed records, which
reference this input record, obtain the current register value.

  One means to achieve this behavior, which I am currently using, employs a
"dfanout" record to write to the output register and to the VAL field of the
input record. Another method would be to make the SCAN field of this input
record "Passive" and to have a dummy record with its SCAN field set to the
periodic interval and its FLNK field directed to the input record.

  Is there a better way to do all of this? What is the reason for
restricting the forward link action only to records that have their SCAN
field set to "Passive".

											Fritz

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System