Figure 5-45 GRAPH MODE – Set. Wayne Kerr 3260B

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Advanced Operation

Figure 5-45 GRAPH MODE – Set

Figure 5-45 shows GRAPH MODE set up to plot a graph of inductance against frequency on a linear scale between 100kHz and 600kHz with the limits set in absolute terms.

5.15.1 GRAPH MODE – Set Parameters

Parameters which are common to IMPEDANCE MODE are described in section 4.7.2—

IMPEDANCE MODE Parameters.

Lin(unit) Log(unit)

Lin(Z) Log(Z)

Sweep

Toggles between Lin(unit) and Log(unit) to set either linear or logarithmic horizontal scale, where unit is the unit of the Sweep parameter (see Sweep, below).

This soft key is displayed only when Log(unit) is selected (above) and when Mode is set to Impedance (Z+θ). It allows selection of

Lin or Log vertical scale, allowing log/log graphs to be plotted.

Note that negative or zero scale limits cannot be plotted on a log scale. Both limits must be set to positive values before pressing

Start, or a warning message will be displayed.

The Start and Stop settings for the graph, which are set by highlighting each in turn with the and navigation keys, then entering the value with the data entry keypad. When Sweep is highlighted the and navigation keys are used to set the

Sweep parameter to Frequency, Bias, Bias (Boost) or Drive

Level.

Step Size

Mode

Abs %

Major/Minor

Term Select

Advanced Operation 5–43

The Step Size is the number of LCD display pixels used for a single point along the graph. The higher the number selected, the coarser the graph but the more quickly it is plotted. Set by highlighting Step Size with the and navigation keys, then select from 1 2 4 8 with the and navigation keys.

When the Mode parameter is highlighted with the and navigation keys, it may be toggled between Impedance… mode or

Transformer… mode parameters (see Major/Minor Term

Select, below) with the and navigation keys. Once this selection is made, the expected Hi and Lo limits for the y axis of the graph may be highlighted with the and navigation keys and the values entered with the data entry keypad. If percentage limits are selected, a Nominal value must also be entered: no units are necessary, this will always match the major term selection.

This soft key toggles between Abs and % (major term only).

When Abs is selected, absolute Hi and Lo limits (i.e. units of the measured parameter) are displayed. When % is selected, a

Nominal value together with Hi and Lo percentage limits is displayed.

The limits and nominal value (if applicable) must be set using the

and navigation keys to highlight each parameter and the data entry keypad to set each value.

Note: The Abs % soft key is not available when the vertical scale is logarithmic.

This soft key toggles between either of the measurement terms selected in IMPEDANCE MODE or TRANSFORMER MODE depending on whether the Mode parameter is set to Impedance… or Transformer…. The graph will be plotted according to whichever of these terms is highlighted.

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Start

View

IMPEDANCE

or

TRANSFORMER

Advanced Operation

When all parameters have been set up, pressing the Start soft key will plot the graph.

As the graph is being plotted, a progress marker at the bottom of the screen shows how complete the graph is and the speed of the marker gives an indication of how long the graph will take to plot.

If the graph is progressing too slowly, perhaps because too small a

Step Size has been selected, it can be aborted by pressing and

holding the Abort key.

Notes:

1) If the range is manually selected and the component characteristics take the graph outside the boundaries of the selected range, that portion of the graph will not be plotted.

2) If incorrect y axis settings are selected, no graph will be seen even though the progress marker will indicate that a graph is being plotted: the graph will actually be ‘plotted’ outside of the display area. The display can be corrected by using the

FIT autoscale function, or by pressing the RETURN soft key and selecting more appropriate limits.

3) An error message shown at the top of the screen indicates that the error occurred somewhere on the sweep.

4) The graph is plotted using the full measurement resolution.

When the graph has been plotted and GRAPH MODE – Set has been reselected with the RETURN soft key, View can be used to redisplay the last graph plotted by the analyzer.

Enters IMPEDANCE MODE or TRANSFORMER MODE according to the Mode selected (see Mode, above) so that measurement parameters may be set up or changed. When the correct measurement parameters are set, the RETURN soft key returns the instrument to GRAPH MODE – Set.

5.15.2 Parameters Available when the Graph is Displayed

FUNCTION

VIEW

FIT

Pressing FUNCTION temporarily crops the graph to display other soft keys available. These are shown indented below:

Pressing VIEW hides the available soft keys and displays the whole graph.

The FIT soft key replots the graph, auto scaling the vertical axis for the best available resolution. This may be done separately for both major and minor terms.

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TOGGLE

When a graph is plotted on the major or minor term, the other term is automatically stored in the background and the TOGGLE soft key can be used to toggle between the two graphical displays.

RESONANCE

Enters RESONANCE MODE. See section 5.16.

PEAK

Aligns the marker with the highest peak in the set frequency range.

DIP

Aligns the marker with the lowest trough in the set frequency range.

NOM>MK

PRINT

RETURN

Replots the graph with the marker position set as the component nominal value. To aid positioning of the marker, its position in both axes is shown at the bottom of the screen. It is moved with the and navigation keys. When GRAPH MODE – Set is reentered with the RETURN soft key, the Nominal and Hi/Lo limits will reflect the replotted graph.

Prints the graph on an Epson-compatible printer after entering

Code 30 from the MAIN MENU.

Returns the analyzer to GRAPH MODE – Set.

Note

If the DUT exhibits high Q resonances, the graph function may miss the peak or trough due to quantized frequency steps. For accurate values at resonance, use the RESONANCE function.

5.15.3 Example

This example will illustrate the procedure for using GRAPH MODE and is intended to familiarize the user with this mode of operation. For this example a linear scale will be used to plot inductance over the frequency range of 100kHz to 600kHz.

1) Enter GRAPH MODE – Set by pressing the GRAPH soft key from the MAIN MENU.

2) Highlight the Sweep parameter with the or navigation key, then using the and navigation keys set it to Frequency.

3) Highlight the Start frequency with the or navigation key and enter the required frequency with the data entry keypad. For this example 100kHz will be entered.

4) Highlight the Stop frequency with the or navigation key and enter the required frequency with the data entry keypad. For this example 600kHz will be entered.

5) Highlight Step Size with the or navigation key, then use the and navigation keys to select 1 2 4 or 8. For this example 2 is selected.

6) Highlight the Mode parameter with the or navigation key, then using the and navigation keys set it to Impedance….

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Advanced Operation

7) Press the IMPEDANCE soft key. This will display IMPEDANCE MODE where the appropriate parameters must be set prior to plotting the graph. Enter the parameters required for the test. For this example they are set to:

AC Meas

L

R

1.00Vac

1.0000kHz—this setting will be overridden when the graph is plotted

DC Bias 0.000 A OFF NORM

Range Auto

Speed Med

ALC off

When the measurement parameters have been set, press the RETURN soft key to return the instrument to GRAPH MODE– Set.

8) Highlight the L and R Hi and Lo limits with the or navigation key, then set each in turn with the data entry keypad. For this example they will be set to:

L Hi: 100.00m

Lo: -100.00m

Lo 1.000Ω

9) Use the Lin(Hz) Log(Hz) soft key to highlight Lin(Hz).

10) Use the Abs % soft key to highlight Abs.

The screen should now look like Figure 5-45.

11) If necessary, press the CALIBRATE soft key and perform the appropriate trims for the

Mode selected. See section 4.3 for details of the trim procedure.

12) Connect the component to the test leads or fixture.

13) Press the Start soft key. A graph will be plotted showing the component characteristics using the measurement parameters and frequency range set (Figure 5-46).