Micro Motion CDM100P - Equations Used in User-Defined Calculations

• If a constant will be used to modify a process variable, you must use the internal
measurement units to derive the constant.
5. Enter a label to be used for the output of the user-defined calculation (the new
process variable).
6. (Optional) Set up a reporting method for the new process variable.
The new process variable can be configured as a display variable or a HART variable,
or assigned to an mA output. It can also be read using digital communications.
Important
The output of the user-defined calculation is based on internal measurement units for process
variables. You may need to convert this value to the configured units before using it in your
application or process.
Related information
Equations used in user‐defined calculations
Measurement units used in user‐defined calculations
Set up concentration measurement
9.7.1 Equations used in user-defined calculations
Each user-defined calculation has an equation and a set of user-programmable constants
and/or user-specified process variables.
User-defined calculation 1 (square root) Equation 9-1:
y=A + B ×
(
a ×
(
b +
(
X × c
))
d ×
(
e +
(
Y × f
))
)
A, B, X, Y
User-programmable constants
a, b, c, d, e, f
User-programmable constants or user-specified process variables
y
Result of calculation
User-defined calculation 2 (exponential) Equation 9-2:
y = e
(
A+
(
B×t
)
+
(
C×t
2
))
e
Natural logarithm
A, B, C
User-programmable constants
t
User-programmable constant or user-specified process variable
y
Result of calculation
Measurement support
Configuration and Use Manual 133