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FS-8700-17 Optomux Driver Manual
FieldServer Technologies 1991 Tarob Court, Milpitas, California 95035 (408) 262-2299 fax: (408) 262-9042
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Page 13
4.4.7 Map Descriptor Example 4 – Triggered Action
This example shows the elements necessary to generate a triggered poll. Even though this map descriptor appears to write to the device
continuously the driver recognizes the opto22_trigger parameter and based on its value will only send the poll when the trigger value is set.
Map_Descriptor_Name, Data_Array_Name, Data_Array_Offset, Function, Node_Name, Length, Scan_Interval, opto22_function , opto22_trigger, DA_Byte_Name
DEVICE77_STAT , CNTR_POSNS , 0 , wrbc , DEV77 , 16 , 0.2s , CLEAR COUNTERS , Yes , COMMAND_ARRAY
This map descriptor
is processed as a
write command and
will be processed
continuously.
The Driver will process this
map descriptor every 0.2
seconds.
In this example, this does not
mean that the command will
be sent to the device every
0.2 seconds. It does mean
that the driver will check to
see if a trigger has been set
every 0.2 seconds.
This keyword value for the
opto22_trigger parameter
tells the driver only to send
this Optomux command if it
has been triggered.
When this parameter is used
the DA_Byte_Name
parameter must also be used.
This is the name of a data array
whose contents will be used to
trigger the command.
The driver looks at the element
found at the Data_Array_Offset
and if that value=1 then the
command is sent. On
completion/error the driver will
change this value to some other
number.