Handing of the unit in computations, Order of operations in equations, Displaying the computed data – Yokogawa Data Acquisition with PID Control CX2000 User Manual
Page 377
App-8
IM 04L31A01-01E
Status of Control Output Terminal Block/Control DIO Expansion Terminal Block's
Contact Output (DO001-DO006, DO101-DO106, DO201-DO206, RO001-RO012)
You can set each contact output status to 1 or 0 and use them for computation.
Internal Switches (SW01-SE36)
You can set each internal switch status to 1 or 0 and use them for computation.
Data Types That Can Be Used in the Computation Function
Computation
Measurement PV/SP
Analog
Logic
type
computation
computation
retransmission computation
Measurement data
Yes
Yes
Yes
Yes
Measurement computed data
Yes
Yes
Yes
Yes
Control measurement data*
No
Yes
Yes
Yes
Internal/external control data
Yes
Yes
Yes
Yes
Constants for measurement
Yes
No
No
No
computation
Constants for control computation No
Yes
Yes
Yes
Communication input data
Yes
Yes
Yes
Yes
Measurement remote input
Yes
Yes
Yes
Yes
Control contact input
Yes
Yes
Yes
Yes
Control expansion contact input
Yes
Yes
Yes
Yes
Control contact output
No
Yes
Yes
Yes
Control expansion contact output No
Yes
Yes
Yes
Internal switches
No
Yes
Yes
Yes
* When PV/SP computation is OFF.
Handing of the Unit in Computations
The unit corresponding to the measured/computed data in the equation is not
compensated
In computations, measured and computed data are handled as values without units. For
example, if the measured data from channel 01 is 20 mV and the measured data from
channel 02 is 20 V, the computed result of 01 + 02 is 40.
Order of Operations in Equations
The order of operators in equations is as follows. Operators are listed in a decreasing
order of precedence.
Type
Operator
(high order of precedence)
Functions
ABS(), SQR(), LOG(), EXP(), TLOG.MAX(), TLOG.MIN(),
TLOG.P-P(), TLOG.SUM(), TLOG.AVE(), CLOG.MAX(),
CLOG.MIN(), CLOG.P-P(), CLOG.AVE()
Conditional expression
[eq1?eq2:eq3]
Power
**
Logical negation
NOT
Multiplication and division
*, /
Addition and subtraction
+, –
Greater than and less than
.GT., .LT., GE., LE.
Equal and not equal
.EQ., .NE.
Logical product
AND
Logical sum and exclusive logical sum OR, XOR
(low order of precedence)
Displaying the Computed Data
The computed data of computation channels can be displayed in each operation display.
Displaying Waveforms and Bar Graphs
The data are displayed in the range defined by the upper and lower limits of the span.
For the procedure in assigning measured data to measurement channels, see section 10.1,
“Assigning Computation Channels and Setting Computing Equations, Constants and Tags.”
For the procedure in setting other items related to the display, see chapter 8, “Operations
for Changing the Displayed Contents.”
Appendix 2 Supplementary Explanation of the Computation Function