FieldServer FS-8700-80 - Manual (Page 25)

McQuay Micro Tech Open Protocol Driver Manual Page 25 of 43
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: [email protected]
Appendix A. Useful Features
Appendix A.1. Scaling
Appendix A.1.1. User Scaling:
The user can specify scaling in the configuration file which allows a value to be scaled before being stored in a Data Array or after being extracted from a data for writing
to McQuay device. This scaling is specified by using the following keywords in Map Descriptor definition.
Data_Array_Low_Scale,
Data_Array_High_Scale,
Device_Low_Scale,
Device_High_Scale…..
Appendix A.1.2. Device Scaling:
The raw values read from a McQuay device may be treated as raw values or they may be scaled. Device scaling is the term used to describe the hard-coded scaling
specified by McQuay for each data field. By applying device scaling the user can avoid details or knowledge of the scaling and used the converted value directly.
If this scaling is required then use the Device_Scaling parameter (see 6.3.2). Note that this parameter needs to be used in conjunction with Field_Name.
There are 5 device scaling methods. Refer to Appendix C.4 and Appendix C.5 for information on the application of these parameters.
Note that when device scaling is applied it is applied without consideration of the raw value. Where the raw value has a special meaning (available in the McQuay packet
documents for the equipment type of interest); this driver does not apply any special consideration to these special values.
As a Client: - Device and User scaling may be applied.
As a Server. Device Scaling and User scaling is not applied. The raw value written to any data location is stored as is and the raw value read from a Data Array used in
formatting the response to a read.
Map_Descriptors
Map_Descriptor_Name , Data_Array_Name , Data_Array_Offset , Function , Node_Name , Address , Length , Field_Name , Device_Scaling , Scan_Interval
Read_field1 , DA_TEMP_SCALED , 0 , Rdbc , Node_200CFC , 1 , 1 , Outdoor Air Temperature - BAS , Yes , 9.5s