Sierra Video Ponderosa 3G Series Routing Switcher - Manual (Page 101)

PONDEROSA
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making delayfields larger, the user can give the router more time to process the
crosspoint commands.
If too many crosspoint commands are received and the router is not able to process them
fast enough, it will output the crosspoint connections as soon as it can. Unexpected
delays in crosspoint output are a sign that the router is being pushed beyond its limits.
The fielddelay value applies to the entire router, not just to the control port on which the
“F” command is received. It is therefore recommended that a single value be settled on
for the fielddelay value, rather than changing the value constantly depending on needs.
Once changed, the router records the value in non-volatile memory and uses it each time
it is powered up, so it is only necessary to change it one time.
Even though a crosspoint isnít changed until the fielddelay time has elapsed, the router
records the new crosspoint state immediately upon receiving the crosspoint change
request,
so a controlling device may receive a report of a crosspoint change before the
change has actually taken effect, and this is more likely to happen the larger fielddelay is.
Since routers currently make no guarantees about when they will report a crosspoint
change anyway, this behavior is usually of no concern. There is a case where this could
cause problems. If the fielddelay value were to be changed while two different devices
were changing the same output, it is possible for the router to report the incorrect input
value for that output. This would happen if the earlier device that changed the output did
so before the fielddelay value was changed, and the later device that changed the output
did so after the fielddelay value was reduced but soon enough that its input value would
be sent to the crosspoint hardware before that of the earlier device. A bit later, the earlier
deviceís input value is sent to the crosspoint hardware, but the router has recorded the
later deviceís input value as being the one in effect. To prevent this scenario, we
recommend that an appropriate fielddelay value be chosen, set, and left alone.
Here is an example of an “F” command:
** F5 Y1,5 X2,6,3 !!
This says that input 5 is to be connected to output 1 on all levels and input 6 is to be
connected to output 2 on level 3, after a delay of 5 fields from the beginning of the field
that follows receipt of the “!” character.