ProSoft Technology PS-QS-1x10-0781 - Manual (Page 19)

FieldServer Configuration Manual Page 19 of 90
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web: www.fieldserver.com
Tel: (408) 262-2299 Fax: (408) 262-2269 Toll Free: (888) 509-1970 email: [email protected]
4.3.5 Active Read on Trigger (ART)
This function is used to effect a single data read per trigger. An example from the Envirotronics Driver is presented below:
// Client Side Map Descriptors
Map Descriptor
Map_Descriptor_Name , Data_Array_Name , Data_Array_Offset , Function , Node_Name , SysPlus_Cmd , Store_Data_Array_Name , Store_Data_Array_Offset , Length
Ed_Rd_Program , Rd_Triggers , 0 , Art , SYSPLUS_01 , Ed_Rd_Program , Ed_Rd_Program , 0 , 1
This command is triggered by writing any value to Data_Array_Name at Data_Array_Offset.
The retrieved data is stored as follows:
Offset from Store_Data_Array_Offset Description
0
Program number
4.3.6 Active Write on Trigger (AWT)
This function is used to effect a single data write per trigger. As with the Wrbx function, the write only occurs when the Data Array is updated. In this case the
updated data is not used to form the write, but updating the Data Array triggers a read of a Secondary Data Array which contains the data to be served in the
write.
In the example below (from the Lutron eLumen Driver) the driver watches the Data Array called ‘Lut_triggers’ (offset 13). If that Data Array element is
updated (even if the value remains unchanged) the the write is triggered. The driver extracts the data from the Secondary Data Array called ‘Set_tlck’ (offset 0)
and forms a message to write this data to the field device.
Only certain drivers support/require the use use of this function. For other drivers, awt is a synonym for wrbx since there is no secondary Data Array to extract
information from.
Note: The driver may extract more data from the array than specified by the ‘length’ parameter. The only way to know how much data is to read that specific
driver’s manual.
Map_Descriptors
Map_Descriptor_Name , Data_Array_Name , Data_Array_Offset , Function , Node_Name , GRAFIK_command , DA_Lut_List , DA_Lut_List_Offset , Length
Set_tck , Lut_triggers , 13 , Awt , LUT_GRF6_0 , Set_tclk , Set_tclk , 0 , 1