FieldServer FS-8704-13 Manuale Utente

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FS-8704-13 GE-SRTP  
 
Driver Manual 
 
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 (408) 262-2299 fax: (408) 262-9042 
Visit our website: www.fieldserver.com          E-mail:  support@fieldserver.com 
 
Page 9 
 
4.4.6  Map Descriptor Example 3 – Handling Bits. 
 
This example shows how to read 1 couple of bits from a data table rather than reading a whole byte. The bits can cross byte boundaries.  Here we read 2 bits 
from table %T starting at bit 8. This is most useful when writing to the PLC in cases where you want to turn o ne particular bit on or off. 
 
Map_Descriptor_Name, Data_Array_Name, Data_Array_Offset, Function, Scan_Interval, node_name, Address, Length, Data_Type, Format 
Read_DI                   , DA_T                  , 100                     , rdbc      , 2.0s             , PLC-1      , 8         , 2         ,  %T          , Bit 
The format parameter tells the 
driver to override the default data 
type and to specifically read bits. In 
this case the bit states are stored in 
the data array in two separate 
elements at DA_T[100] and 
DA_T[101]