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FS-8700-123 MetOne Particle Counter Serial Driver Manual Page 11 of 26
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: support@fieldServer.com
4.6. Map Descriptor Example 2 – Write Hold (or Sample) Times to a Device.
In this example the driver writes the hold time to the field device. The time is specified in seconds. A max of 23 hours 59 minutes
and 59 seconds can be specified. To write Sample Times simply change the Met1_Function to ‘Sample Time. The driver extracts
the time from the response and stores the hours at the specified offset, the minutes in the next Data Array location and the seconds
in the 3
rd
location.
// Client Side Map Descriptors
Map_Descriptors
Map_Descriptor_Name, Data_Array_Name, Data_Array_Offset, Function, Node_Name Met1_Function, Length
Write_Time, DA_TIMES, 0, WRBX, MET1, Hold Time , 1
4.7. Map Descriptor Example 3 – Read the operating mode.
In this example the driver reads the operating mode from the field device. The driver stores a single element of data extracted from
the response. The driver stores a ‘C’ to indicate the field device is counting, a ‘H’ to indicate the device is holding and an ‘S’ to
indicate that it has stopped. If the mode is not recognized the driver store s a ‘?’. If another protocol reads these states from the
FieldServer it will probably display the ASCII value corresponding to each mode letter: ‘C’=67 ‘H’=72 and ‘S’=83
// Client Side Map Descriptors
Map_Descriptors
Map_Descriptor_Name, Data_Array_Name, Data_Array_Offset, Function, Node_Name Met1_Function, Length, Scan_Interval
Write_Time, DA_MODE, 0, rdbc, MET1, Mode , 1, 1.0s
The driver will extract the time in
seconds from the Data Array
specified here and use it to form
the command message to the
field device.
The location in
the Data Array
This function ‘wrbx’ tells
the driver to only send the
command each time the
value found in the
specified DA:offset is
updated. Update means
each time some other
protocol writes to this
DA:offset
Change this to
‘Sample Time’ to
command a sample
time or make two
Map Descriptors –
each with the correct
time function.
Tells the
FieldServer that
one element of
the data array is
reserved for this
Map Descriptor.