8-4
IM WT1801-01EN
Values Substituted in Operands
• The unit of TI values is seconds.
• η1 to η4 are displayed as percentages (see in appendix 1 in the getting started guide, IM WT1801-03EN).
However, in this section ETA1 to ETA4 are described as ratios.
Example When η1 is 80%, ETA1 is 0.8
• The U1 in PHIU1U2 represents the voltage signal of the element whose element number is the smallest in
the wiring unit (ΣA, ΣB, or ΣC). For example, if input elements 2, 3, and 4 are assigned to wiring unit ΣA,
PHIU1U2 is the phase difference between the voltage signals of input elements 2 and 3.
• User-defined equations can use other user-defined equations with smaller numbers as operands. For
example, the equation for user-defined function F3 can be set to F1( ) + F2( ). This allows equations that
would otherwise exceed 50 characters in length to be computed. This can be accomplished by for example
setting equations in F1 and F2, and then adding or dividing those equations in F3. This feature is also
convenient when defining multiple equations that include common operands. For example, you can set
common operands in F1, and then set F4 as F3( ) divided by F1( ) and set F5 as F4( ) divided by F1( ).
However, if you enter a user-defined equation with a number that is greater than or equal to its own number,
correct results will not be obtained. For example, if you set user-defined function F3 to F1( )+F3( ) or to
F1( )+F4( ), the computed result will be displayed as “-------” (no data) or “-OF-” (overflow).
Operators
The following operators can be used in equations.
Operator
Example
Description
+, –, *, /
U(E1,OR1)–U(E2,OR1)
Basic arithmetic
ABS
ABS(P(E1,ORT) + P(E2,ORT))
Absolute value
SQR
SQR(I(E1,OR0))
Square
SQRT
SQRT(ABS(I(E1,OR3)))
Square root
LOG
LOG(U(E1,OR25))
Natural logarithm
LOG10
LOG10(U(E1,OR25))
Common logarithm
EXP
EXP(U(E1,OR12))
Exponent
NEG
NEG(U(E1,OR12))
Negation
Number and Type of Characters That Can Be Used in Equations
• Number of characters: Up to 50
• Usable characters: Spaces and all characters that are displayed on the keyboard
On the keyboard, press
to enter operand and equation characters. The characters that you can select are
indicated below.
ABS(
PPK(
HVF(
RMS(
SQR(
MPK(
HCF(
MN(
SQRT(
CF
KFACT(
RMN(
LOG(
TI(
EAU(
DC(
LOG10(
THD(
EAI(
AC(
EXP(
THF(
PLLFRQ(
PC(
NEG(
TIF(
–––
–––
Equation Examples
An equation to determine the rms value of the harmonic components of the voltage signal of input element 2.
(Total rms voltage value)
2
- (Rms value of the fundamental voltage signal)
2
SQRT(SQR(U(E2,ORT))–SQR(U(E2,OR1)))
8 Computation