Banner SureCross DX80 Wireless Networks - Manual (Page 106)

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Units Conversion
Signed/Unsigned Unit Types
Using the signed or unsigned unit type allows the user to generically map any input to any output. The signed and unsigned unit types read the
null and span parameters to create the linear translation between one scale and another. The output type is set to mA or V.
Output = (Fullscale/Span)(InputValue − Null) + Offset
Output Scale Fullscale (range) Offset
0–20 mA 20 mA 0 mA
4–20 mA 16 mA 4 mA
0–10V 10V 0V
Fullscale. Defined in the table; the output range
Span. The total range of values mapped to the output
Null. The starting point for the output scale
Input Value. The value mapped to the output
Offset. Defined in the table; the starting output value.
Temperature Map Example
Map a temperature input from a Node to a 4–20 mA output. The starting temperature is −20°F and the last temperature will be 50°F (4 mA =
−20°F, 20 mA = 50°F). This defines the null as −20°F and the span as 70.
With an input temperature value of −5°F, the output value will be:
Output = (Fullscale ÷ Span)(InValue − Null) + Offset
(Fullscale ÷ Span) = 16 ÷ 70 = 0.22857
(Value − Null ) = −5 − (−20) = 15
Offset = 4
Output = 0.22857 × 15 + 4 = 7.42 mA
Distance Map Example
Map a distance input from a Node to a 0–10V output. The starting distance is 200mm and the last distance will be 2000mm (4 mA = 200mm,
20 mA = 2000mm). This defines the null as 200 and the span as 1800.
With an input distance reading of 1560mm, the output value will be:
Output = (Fullscale ÷ Span)(InValue − Null) + Offset
(Fullscale ÷ Span) = 10 ÷ 1800 = 0.00555
(Value − Null ) = 1560 − 200 = 1360
Offset = 0
Output = 0.00555 × 1360 + 0 = 7.54V
Alarm Conditions
For special alarm conditions, consult the factory. The default alarm conditions are as follows:
Unsigned Alarm: 0xFFFF
Signed Alarm: 0x7FFF