Digital Multimeter HDM3055 Series Manual

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Step 2: Press on the front panel to open a menu that specifies

whether the DMM will beep to indicate a successful diode test.

Diode measurements behave as follows:

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Frequency and Period

This section describes how to configure frequency and period measurements from the front panel.

Step 1: Configure the test leads as shown.

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Step 2: Press [Freq] on the front panel and then use the first softkey to choose either frequency

or period measurement.

Step 3: Press Range to select a range for the measurement. (Auto (autorange) automatically

selects the range for the measurement based on the input. Autoranging is convenient, but it results

in slower measurements than using a manual range. Autoranging goes up a range at 120% of the

present range, and down a range below 10% of the present range.

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Step 4: Press AC Filter and choose the filter for the measurement. The instrument uses three

different AC filters that enable you either to optimize low frequency accuracy or to achieve faster

AC settling times following a change in input signal amplitude.

The three filters are 3 Hz, 20 Hz, and 200 Hz, and you should generally select the highest

frequency filter whose frequency is less than that of the signal you are measuring, because

higher frequency filters result in faster measurements. For example, when measuring a signal

between 20 and 200 Hz, use the 20 Hz filter.

If measurement speed is not an issue, choosing a lower frequency filter may result in quieter

measurements, depending on the signal that you are measuring.

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Step 5: Press Gate Time and choose the measurement aperture (integration time) of  10 ms,

100 ms (default), or 1 s.

Step 6: Press Timeout to control how long the instrument waits before timing out on a frequency

or period measurement when no signal is present. When set to 1s, the instrument waits 1 second

before timing out. When set to Auto, the wait time varies with AC filter bandwidth; for the faster

bandwidths, the instrument waits a shorter time before timing out and returning 0.0. This is

advantageous in manufacturing test systems where a DUT failure may result in no signal;

in this case, the failure can be detected sooner, speeding up test throughput.

NOTE For accurate displayed statistics of AC measurements in Front Panel mode, the default manual

trigger delay ([Acquire] > Delay Man) must be used.

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Secondary Measurements

Most measurement functions allow you to select and display a secondary measurement function.

Secondary measurements can be displayed in the Number and Bar Meter displays only. For example,

a thermistor temperature measurement (primary) and the resistance measurement made on the

thermistor (secondary) are shown below:

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To select a secondary measurement from the front panel, first select the primary measurement

function and then press Display:

Press 2nd Meas and select the secondary measurement.

The primary measurement functions and their associated secondary measurements for each DMM

model are:

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Where:

l Sensor - The raw sensor value; ohms for thermistor/RTD.

l Input/Ref - The DC signal voltage and the DC reference voltage measurements.

1 After making one or more primary measurements for approximately 4 seconds, the DMM makes

one secondary measurement.

Triggering and Readings

The trigger model and large reading memory provide versatile capabilities for a wide variety of applications.

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Instrument trigger model

Acquiring measurements on the DMM is done as the result of triggering. This section describes

how to configure triggering.

Pressing [Acquire] opens the following menu:

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The menus above allow you to configure measurement triggering, and you can also use the VMC

Out softkey to set the edge slope of the VM Comp (voltmeter complete) output on the instrument's

rear panel. This connector issues a signal whenever the voltmeter finishes taking a measurement to

allow you to signal other devices in a measurement system.

For accurate displayed statistics of AC measurements in Front Panel mode, the default manual trigger

delay ([Acquire] > Delay Man) must be used.

The (Trg Src) menu allows you to select one of these trigger sources: