FieldServer A Sierra Monitor Company FS-8700-123, Руководство пользователя

Страница: 11 / 22

FS-8700-123 MetOne Particle Counter Driver Manual Page 11 of 22
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
5.5 Map Descriptor Example 2 – Write Hold (or Sample) Times to a Device.
(Important Note: See Appendix B.3
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 a single value from the specified Data Array. It treats
this value as the number of seconds. Thus to specify a sample time of 1 hour 2 minutes and 3 seconds load the Data Array with 3723.
//, , , , 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
5.6 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 stores 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.