User Guide

FS-8700-21 LonWorks Manual Page 28 of 62
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Appendix A.9. Filtering SNVT Variables
Appendix A.9.1. SNVT_Option Field
This field can be used to isolate a specific record within a complex SNVT. Appendix D shows which SNVTs are
currently attributed with SNVT_Option capabilities.
Appendix A.9.2. SNVT_Units Field
The measurement units of a SNVT is fixed as far as it is transported across the LonWorks network, but by the
setting of the SNVT_Units field it is possible to specify how the data is made available in Data Arrays. For example
SNVT_temp_f is always transported across the LonWorks network as degrees Celsius, but by setting the
SNVT_Units field to Deg_F the measurement units of the Map Descriptor’s data will be set to degrees Fahrenheit.
The following table shows which SNVT’s currently have SNVT_Units capabilities.
SNVT_Type
SNVT_Option
SNVT_Units
Length
Measurement Units
SNVT_press_f
N/A
Inch_H20
1
Inches of water
SNVT_press_p
N/A
Inch_H20
1
Inches of water
SNVT_temp
N/A
Raw
1
Raw, unadjusted data
Deg_C
1
Degrees Celsius (°C)
Deg_F
1
Degrees Fahrenheit (°F)
SNVT_temp_f
N/A
Deg_C
1
Degrees Celsius (°C)
Deg_F
1
Degrees Fahrenheit (°F)
SNVT_temp_p
N/A
Raw
1
Raw, unadjusted data
Deg_C
1
Degrees Celsius (°C)
Deg_F
1
Degrees Fahrenheit (°F)
SNVT_switch
1
All
Raw
2
Raw, unadjusted data
Value
Raw
1
Raw, unadjusted data
Percent
1
Percent (%)
State
Raw
1
Raw, unadjusted data
1
See Also Appendix A.8