BACnet PTP Serial Driver Manual
Page 18 of 34
Appendix A.5. 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.
Appendix A.5.1. Method 1
– Using an Offset/User Table
//set up a look up table
Offset_Table
Offset_Table_Name
, Table_String
, Table_Index_Value
FIRE_ALRM_TEXT
, SYSTEM READY
, 1
FIRE_ALRM_TEXT
, ALARM , 2
FIRE_ALRM_TEXT
, MAINTENANCE
, 3
FIRE_ALRM_TEXT
, OFF-LINE , 4
FIRE_ALRM_TEXT
, IN SERVICE , 5
FIRE_ALRM_TEXT
, OTHER , 6
Data_Arrays
Data_Array_Name , Data_Format , Data_Array_Length
DA_MI_01
, UINT16
, 100
Map_Descriptors
Map_Descriptor_Name , Data_Array_Name , Data_Array_Offset , Function , Node_Name
CMD_MI_01
, DA_MI_01
, 0
, Passive , N1 11
, Data_Type , Object_ID , Length , State_Text_Array
, MI
, 1
, 1
, Fire_Alrm_Text
Appendix A.5.2. Method 2
– Using a Single Data Array
Data_Arrays
Data_Array_Name , Data_Format , Data_Array_Length
DA_MI_01
, UINT16
, 100
DA_STATE_TXT
, BYTE
, 200
Preloads
Data_Array_Name , Preload_Data_Value
, Preload_Data_Format , Preload_Data_Index
DA_STATE_TXT
, MyState1 MyState2 MyState3
MyState4 MyState5 MyState6
, String
, 0
Map_Descriptors
Map_Descriptor_Name , Data_Type , Object_ID , Function , Data_Array_Name , Node_Name , Length , State_Text_Array
CMD_MI_01
, MI
, 1
, Passive
, DA_MI_01
, N1 11
, 1
, Da_State_Txt
Valid values are 1
to 16.
