FieldServer Spectronics FS-8700-42 User Manual
Page 13
FS-8700-42_Spectronics
Driver
Manual
Page
13
of
15
FieldServer Technologies
1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com
Tel
: (408) 262-2299 Fax: (408) 262-9042 Toll_Free: 888-509-1970 email: [email protected]
Appendix A. Advanced Topics – Spectronics
Appendix A.1. Default Data Types
When a Spectronics address range is specified, a particular Data Type is implied. The
defaults are as follows:
Address range
Data_Type
Function Code (Write)
Function Code (Read)
40001 - 49999
Register
16
3
30001 - 39999
Analog _Input
n/a.
4
10001 - 19999
Digital_Input
n/a.
2
00001 - 09999
Coil
15
1
Appendix A.2. Single Writes
When writing the default data types can be overwritten using the “Single_Coil” and
“Single_Register” settings as part of the Map Descriptor configuration. In that case the
Function codes for writes will be as follows:
Address range Data_Type
Function Code (Write)
40001 - 49999
Single_Register 6
30001 - 39999
Coil
5.
Example: FC 6 = Write Single Register
Add a parameter to the Spectronics client side Map Descriptor called Data_Type.
If you specify the Data_Type as Single_Register and the Function as WRBC or WRBX,
then a Spectronics poll with FC 6 will be generated.
Of course Single_Register implies a length of one, and even if you try to set the length
longer in the csv file, the length is limited to 1 in the driver.
Appendix A.3. Write-Thru Operation
Consider a client Map Descriptor that is configured to read data using a FC 3 (Read Multiple
Register) operation. It is now possible do a write thru operation on the existing Client Map
Descriptor by storing data to the Client Map Descriptors Data Array.
The Write Cache Map Descriptor that is created will use the following function codes
depending on the Cache Map Descriptor Length and the Clients Node Type.
Single Register Write - FC 6 - When the length of the Cache Map Descriptor is one. This will
normally be the case.
Multiple Register Write – FC 16 - When the length of the Cache Map Descriptor is larger
than one or the Node_Type has been set to “Block_Mode”.