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IM 253710-01E
1.7
Numerical Computation
By making use of the measurement function data and the measurement and
computation function (see section 1.2), additional numerical computation can be carried
out. In addition, a function is provided in which the equation used in determining the
measurement function data can be selected.
Delta Computation «For procedures, see section 10.2.»
In the normal measurement mode, the sum or difference of the instantaneous values
(sampled data) of the voltage or current between elements 1, 2, and 3 can be used to
determine the measurement functions,
∆
Urms,
∆
Irms,
∆
Umn,
∆
Imn,
∆
Udc,
∆
Idc,
∆
Uac,
and
∆
Iac. This is called delta computation. The delta computation can be used, for
example, to perform star-to-delta transformation of a three-phase AC circuit. For the
equation, see Appendix 3. The measurement and computation periods are the same as
those described in section 1.2, “Measurement Modes and Measurement/Computation
Periods.”
User-defined Functions «For procedures, see section 10.3.»
An equation can be created (defined) by combining the measurement function symbols
and operators. The numerical data corresponding to the equation can then be
determined. The combination of a measurement function and element number (Urms1,
for example) constitutes an operand.
Four equations (F1 to F4) can be defined for each measurement mode (normal and
harmonic).
Operators
There are 11 types of operators: +, –,
∗
, /, ABS (absolute value), SQR (square),
SQRT (square root), LOG (logarithm), LOG10 (common logarithm), EXP (exponent),
and NEG (minus sign).
Operands
There can be up to 16 operands in one equation.
Equation for the Apparent Power «For procedures, see section 10.4.»
The apparent power is determined by the product of the voltage and current. The
voltage and current can be selected from the three types, the true rms value, the rectified
mean value calibrated to the rms value, and the simple average as explained in
“Determining the voltage and current” in section 1.2, “Measurement Modes and
Measurement/Computation Periods.”
