Viconics VT8600 Series BACnet Integration Guide - Manual (Page 32)

VT8600 Series BACnet ® Integration Manual 32
Viconics Technologies Inc. | 9245 Langelier Blvd. | St.-Leonard | Quebec | Canada | H1P 3K9 | Tel: (514) 321-5660 | Fax: (514) 321-4150
028-0437-00 www.viconics.com | [email protected] March 2015
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Status objects.
Object examples in this category: BV36 / Filter Alarm, AV21 / PI Heating Demand. All status objects are
writable.
Writing and binding to the priority array 4 to 16 property is a method to use IF the requirement is to lock the
controller program and prevent statuses from being flagged based on the internal operation of the controller
application programming.
When writing and binding to the priority array 4 to 16, the control will NOT store and archive to flash memory
and will simply use it in RAM. As soon as the new present value is received in priority array 4 to 16, the
controller will use this new present value in all its internal control logics and functions.
When writing and binding to the priority array 4 to 16, the controller internal control logics and functions ARE
bypassed, and the controller will NOT operate with its own present values, but will be forced to use the last
write commands received on priority array 4 to 16 for its built-in internal control logics and functions. HOWEV-
ER, since these present values are only stored in RAM and not in flash, if a power reset occurs, the override
type function will be lost and the controller will start to operate using the relinquish default value. If the override
type function is required, a new write command to priority array 4 to 16 is needed.
The controller fully supports native and BACnet compliant priority array 1 to 16
write commands. This simply means that a write value at level 4 has a higher
authority than a write at level 9.
When writing and binding to priority array 4 to 16, you locally identify if an
override is effective on a status object using the service view. The point will be
highlighted in
RED indicating a write command to priority array 4 to 16. In this
case, the present value used by the controller internal control logics is by-passed
and the value displayed and used is the last write command received at priority
array 4-16.
The ONLY way to release the override due to the use of writing to priority array
4 to 16 is to send a write NULL command to the proper priority array currently
locking the controller.
Status and outputs
are processed by
BACnet Priority
Array 4 -16 value
BACnet Relinquish
Default network write
Internal controller program
under normal operation
BACnet Relinquish
Default value
BACnet Priority
Array 4 -16 value