FS-8700-73 BACnet MSTP Driver Manual
Page 22 of 48
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Appendix A.5.
Relinquishing Control of a Point as a Client
It is possible to relinquish control of a point by writing a null to the correct priority level. The following example illustrates how this is done.
Map_Descriptors
Map_Descriptor_Name , Data_Type , Function , Scan_Interval , Data_Array_Name , Data_Array_Index , Node_Name , Address , Length , Write_Priority , Service
CMD AO
, AO
, Rdbc
, 1.0s
, DA AO
, 2
, N1 1
, 1
, 1
, 7
, -
CMD AO Rel
, AO
, Wrbx
, 1.0s
, DA AO
, 3
, N1 1
, 1
, 1
, 7
, Relinquish
Appendix A.6.
BACnet State Text Preload
BACnet Multistate Objects have a State_Text property. This property is defined as an array of character strings representing descriptions of all possible states of the
Present_Value. The number of descriptions matches the number of states defined in the Number_Of_States property. The Present_Value, interpreted as an integer,
serves as an index into the array.
When Multistate Objects are configured on a BACnet server it is necessary to define the State_Text property. This section illustrates how to define the State_Text
character strings and how to associate these definitions with Multistate Server Map Descriptors.
The maximum permitted length of any State_Text string is 50 characters.
Map Descriptor CMD AO is a Read
Map Descriptor that will write at
priority 7 if a write-through occurs
Map Descriptor CMD AO Rel is a Write-on-Change
Map Descriptor that will write a NULL at priority 7
(i.e. release Priority Array entry 7) when written to.
Note that the length must be 1.
