Rosemount 3095FB - Method 2: Define Scale and Offset

Model 3095FB Multivariable Transmitter with Modbus Protocol
Modbus Protocol Guide
Page 38 of 79
5.3.1.2 Method 2: Define Scale and Offset
To configure the integer scaling of PVs using Method 2, follow this procedure:
1. Set a maximum integer.
2. Calculate the scale factor for each PV.
3. Calculate the offset for each PV
4. Write the values calculated above to the corresponding registers.
The following formula is used to calculate the scale factor and offset:
[Equation 2] y = A(x) - (B - 32,768)
Where: y = scaled integer output (see Table 5-4)
x = measured value of PV in current units (see Table 5-1)
A = scale factor (see Table 5-10)
B = offset of scaled integer (see Table 5-10)
Table 5-8 PV Scaled Integer X Value
Modbus Access
DESCRIPTION
Address
Address
Type
Attributes
Functional
Area
Data / Control
0469,
0470
FP register RW PV Scaled
Integers
DP_x1
0471,
0472
FP register RW DP_x2
0473,
0474
FP register RW SP_x1
0475,
0476
FP register RW SP_x2
0477,
0478
FP register RW PT_x1
0479,
0480
FP register RW PT_x2
*Attributes: R/W = Read/Write, RO = Read Only, WP = Write Protected
**These registers are available at multiple Modbus addresses (see Section 2.3)