Yokogawa DR240 - Manual (Page 115)

App-3 IM DR231-11E
Computing Equation
App
Priority of operators
The priority of operators in a computing equation is as follows. The operators are placed in order
from the highest priority.
Type Operators
Function ABS(), SQR(), LOG(), LN(), EXP(), MAX(), MIN(), P-P(), SUM(), AVE(),
PRE(), HOLD():, RESET():
Exponentiation **
Signs, logical negation +, -, NOT
Multiplication, division *, /
Addition, subtraction +, -
Greater/less relation .GT., .LT., .GE., .LE.
Equal/not equal relation .EQ., .NE.
Logical product AND
Logical sum, exclusive OR OR, XOR
Range when computing
When the value exceeds
±
10 308 during the computation, computation error (overflow) occurs.
Units in computing equations
In computations, measured data are handled as numbers without units. For example, if the
measured data of channel 001 is “20 mV” and the measured data of channel 002 is “20 V”, the
computed result of “001+002” becomes “40”.
Limitations in computing equations
Multiple operators can be used in 1 computing equation. But, there are following limitations.
- Number of characters that can be used : 40 characters
- Total number of channel numbers and constants: 16 (Computation error occurs when 16
exceeded, and the computed result becomes +OVER or -OVER)
- Computation channel numbers: Computation channel numbers less than the current
computation channel number can be used as variables within the computing equation.
Example: A02=001+A01
←
Computation channel numbers greater than or equal to A03 can
not be used in this computation.
- Statistical operators (TLOG. or CLOG.) can only be used once in 1 computing equation.
Control of the computing operation
There is a method to control using the data collection software and the method to control using
the event/action function described on the next page.
- Control using the data collection software
This software allows for the start/stop of the computation, and the clearing of the computed
result (select between just clearing or immediately compute after clearing).
Computation start Computation start
Computation stop Computation clear & start
Computed data
App.1 Computing Equation