Sierra Video Pro XL Series 8 - Manual (Page 56)

SIERRA VIDEO
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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.
Basic “G” Command:
Action From Syntax
Modify Host G command_name { arguments… } ~
Query Host G command_name { arguments… } ~
Query Response Router G command_name { arguments… } ~
Modify is Protected:
Yes
Report Changes: No
The command "G" is used to query or modify a router configuration parameter or parameters.
Summary lines at the start of each command section describe, for each type of command action
(Modify, Query, or Query Response), whether the command is sent to the router or from the
router and what the syntax of the command is. They also indicate whether or not the modify form
of the command is password-protected or not (“Modify is Protected”) and whether or not the
command participates in automatic reporting of parameter changes (“Report Changes”) as
described under the “G REPORT_CHANGES” command.
Each command has three possible syntax forms: