Installation & Operation Manual - Model AVC5000
Contents of this Manual are Subject to Change Without Notification
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The standard objects; DEV, AI, AV, AO, BI, BV, and MSI support required properties for those
object types. Object_Name is writable with provision for 64-character maximum length names.
BI Inactive_Text and Active_Text, and MSI State_Text are writable.
Each AI/AV/AO object’s Units property automatically changes
to the appropriate unit for US or
SI measurement based on the value of MSI3 and MSI4. Internally Present_Values are stored in
US units and converted to/from SI units only when read or written.
Standard object property values other than Present_Value shall be derived as follows:
•
Object_Identifier: generated automatically from request
•
Object_Type: generated automatically from request
•
Object_Name: writable
•
Polarity: always NORMAL
•
Units: Reference Table above, MSI3 and MSI4
•
State_Text, Inactive_Text, Active_Text: writable
•
Status_Flags: always {FALSE,FALSE,FALSE,FALSE}
•
Event_State: always NORMAL
•
Out_Of_Service: always FALSE
The internal Airflow Control loop dictates the Airflow Actuator Position (AO1) at a priority of 10.
Devices external to the AVC that need to control the actuator directly shall use higher priority
levels (9, 8, 7 etc.).
Objects; AI,AV,AO shall support the COV_INCREMENT property which shall also be writable.
7.1.1 Save Active Configuration to Nonvolatile Flash Memory
The AVC has both volatile (RAM) and nonvolatile (Flash) memory types. RAM memory has no
limit of the number of writes in a lifetime. Nonvolatile Flash memory has a limited lifetime
number of write cycles. RAM memory is used by the controller to store and retrieve active
values which are to be used for control. Any values in RAM are lost when the controller is
powered down. The Values stored in Flash memory are copied to RAM memory during the
power up sequence of the controller.
Writing a value of one (1) to the BACnet Object BV2 will cause the controller to copy the active
volatile configuration over to the nonvolatile Flash memory. Once values have been saved to
nonvolatile memory they will retain their value through power cycles. Nonvolatile Flash
memory has a limited lifetime number of write cycles which can be monitored via the BACnet
Object AI7.
7.2 Commanded Points
Only object AO1 supports BACnet command prioritization for writable Present_Values. AO1
shall include the Priority_Array and Relinquish_Default properties and their corresponding
behaviors with respect to controlling the value written to the object’s Present_Value.
The AVC
proactively manages each of these Priority_Arrays and updates the Present_Value accordingly.
