MR8740、MR8741_user_manual_eng_20191016H.pdf - 第244页

10.2 Settings for Waveform Calcula tion 232 Waveform calculation results are displayed o n the Waveform screen. 5 When finish ed entry, select [Con firm] . The entered equation is displayed in the [Equation] field. The s…

10.2 Settings for Waveform Calculation

231

Chapter 10 Waveform Calculation Functions

10.2 Settings for Waveform Calculation

Procedure

To open the screen: Right-click and select [STATUS]  [Wave Calc] sheet

Enable the Waveform Calculation function.

Move the flashing cursor to the [Wave Calculation] item,

and select [On].

Specify the waveform calculation range.

Move the flashing cursor to the [Calc Area] item.

Select

See: "6.2 Specifying a Waveform Range (A/B Cursor)" (p.124)

Perform calculation settings.

Move the flashing cursor to the [Equation] column of the

calculation to be set and select [Enter EQN].

A dialog is displayed for entering a calculation equation.

Select a calculation equation.

See: "Waveform Calculation Example" (p.236)

Whole Wave Applies calculations to the whole waveform. (default

setting)

A-B Wave

Applies calculations to the data between A/B cursors.

.Calculation No.

Enter constants

Constants must have been previ-

ously entered on the [CONST.]

(

p.234)

Enter numerical

values and symbols

Enter calculation

operators

When selecting [A-B Wave], specify the

calculation range using the A/B cursors on

the Waveform screen.

If no measurement data has been ac-

quired by the instrument, first measure

once so that the range can be specified for

calculations to be applied to subsequent

measurements.

If "=" is displayed

The entered calculation equation is syn-

tactically correct.

If "?" is displayed

The equation has a syntax error.

The cursor is placed at the location of the

error to facilitate correction.

• Are parentheses correctly matched?

• Has a multiplication operator "

" been

omitted?

10.2 Settings for Waveform Calculation

232

Waveform calculation results are displayed on the Waveform screen.

When finished entry, select [Confirm].

The entered equation is displayed in the [Equation] field.

The scale (maximum and minimum vales) of the calculation results

has a default setting of [Auto]. If you want to scale the results, set

the maximum and minimum values under [Manual].

See: "Changing the display method for calculated waveforms" (p.235)

(As occasion demands)

Set auto saving (p.88).

Execute the calculations.

Applying Calculations to Existing Data

At the [Wave Calc] sheet, select [Exec].

To calculate while measuring

Click [START] to start measurement.

Calculation waveforms are displayed after loading waveforms.

10.2.1 Displaying the waveform calculation results

Example: Waveform of the calculated absolute value of the waveform of CH1. Calcu-

lation equation = ABS(CH1)

CH1 Waveform

Absolute Value

Waveform

To copy settings from one calculation to another:

Settings can be copied at the [Wave Calc] sheet.

See: "7.8 Copying settings to other channels (calculation No.) (Copy function)" (p.160)

10.2 Settings for Waveform Calculation

233

Chapter 10 Waveform Calculation Functions

About calculation equations _____________________________________

Operators

See: "10.3 Waveform Calculation Operators and Results" (p.237)

Entering Calculation Equations

• Each entered calculation equation may contain up to 80 characters.

• Each constant in a calculation equation may contain up to 30 digits.

• For multiplication, use [*]. For division, use [/].

• Entering a long, complex formula such as that shown below will cause "?" to

be displayed. Separate the formula into two shorter formulas.

• When dividing by 0, an overflow value is output.

(For positive values, +9.9999E+29. For negative values, -9.9999E+29.)

• The result of calculation Z

can be used in other calculation equations. How-

ever, the Z

th equation can only refer to the results of equations up to Z

n-1

(Example: Equation Z

can include the results of equations Z

through Z

Using the MOV, SLI, DIF and DIF2 operators in an equation

The number # after a comma within parenthesis (_,#) for each operation is set to

the calculation operator.

When calculation results overflow (OVER)

• The value that indicated by the A/B cursor is not a correct value.

• When [Scale] is set to [Auto], waveforms appear at the top or bottom edge of

the screen. This makes calculation result overflow obvious.

Operator Name Operator Name

ABS Absolute Value DIF2 2

Derivative

EXP Exponent INT2 2

Integral

LOG Common Logarithm SIN Sine

SQR Square Root COS Cosine

MOV Moving Average TAN Tangent

SLI Movement parallel to the

time axis

ASIN Inverse Sine

DIF 1

Derivative ACOS Inverse Cosine

INT 1

Integral ATAN Inverse Tangent

PLCS Digital Voltmeter Unit PLC de-

lay time shift

ABS(CH1)+CH2*CH3-(CH4+CH5)*ABS(CH4)/DIF(CH1, 1)

12 3

Operator Setting Choice Setting Examples

MOV

(Moving Average)

SLI

(Parallel Movement)

Set the number of points to move.

Setting Range

MOV (Moving Average): 1 to 5000

SLI: -5000 to 5000

Calculate the 10-point mov-

ing average of CH1:

MOV(CH1,10)

DIF

(Derivative)

DIF2

(2nd Derivative)

Specify the sampling interval for dif-

ferentiation.

"1" is normally acceptable, but this

should be set larger to capture fluc-

tuation values of slowly changing

waveforms.

DIF and DIF2 Setting Range: 1 to

5000

Differentiate CH2 using a 20-

point sampling interval:

DIF(CH2,20)