Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 379)

App-10
IM 04L31A01-01E
Appendix 3 Meaning and Syntax of Equations
This section explains in detail the meaning and syntax of equations. It is a supplement
to the information covered in “Computation Function” in section 1.18, “Computation and
Report Functions (Option)” and section 1.19, “Equation for Control Computation.”
Four Arithmetic Operations
The data that can be used in equations is as follows: measurement data (01-20),
computation data (31-60), control data (101-118, 201-248), constants (K01-K30),
communication input data (C01-C30), remote input status of measurement alarm option
terminal block (DO1-DO8), contact input/output status of control output terminal block
(DI001-DI006, DI101-DI106, DI201-DI206, DO001-DO006, DO101-DO106, DO201-
DO206), contact input/output status of control DIO expansion terminal block (RI001-
RI012, RO001-RO012), control measured data (CI01-CI10), constants control
computation (W01-W36), and status of internal switches (SW01-SW36). See page App-
8 for the data that can be used with control computation and measurement computation.
Equation Examples
• Addition
01+02
(Determines the sum of the measured values of channel 1 and channel 2.)
• Subtraction 01–02
(Determines the difference of the measured values of channel 1 and
channel 2.)
• Multiplication 01*K03
(Multiplies constant K03 to the measured value of channel 1.)
• Division 01/K02
(Divides the measured value of channel 1 by constant K02.)
Note
By setting an equation similar to the one shown below, you can determine the accumulation
of a specified channel (in this case channel 01) and make the result the computed value of
computation channel 31. The computing equation of computation channel 31: 31+01
Power and Other Computations
The data that can be used in equations is as follows: measurement data (01-20),
computation data (31-60), control data (101-118, 201-248), constants (K01-K30),
communication input data (C01-C30), remote input status of measurement alarm option
terminal block (DO1-DO8), contact input/output status of control output terminal block
(DI001-DI006, DI101-DI106, DI201-DI206, DO001-DO006, DO101-DO106, DO201-
DO206), contact input/output status of control DIO expansion terminal block (RI001-
RI012, RO001-RO012), control measured data (CI01-CI10), constants control
computation (W01-W36), and status of internal switches (SW01-SW36). See page App-
8 for the data that can be used with control computation and measurement computation.
You can also add the computation elements within the parentheses ().
Equation Examples
• Power
01**02
(Determines the measured value of channel 1 to the power of the
measured value of channel 2.)
• Square root SQR(02)
(Determines the square root of the measured value of channel 2.)
• Absolute value ABS(02)
(Determines the absolute value of the measured value of channel 2.)
• Common logarithm LOG(01)
(Determines the common logarithm (log
10
) of the measured value of
channel 1.)