Agilent Technologies N3280A User Manual download pdf (Page 45)

Programming the DC Source - 5

Current Ranges

The dc source has three current measurement ranges. The command that controls the ranges is:

SENS:CURR:RANG <value>, (@<channel list>)

Enter the value of the current that you expect to measure. When the range is set to MAX, the maximum

current that can be measured is the maximum rating of the unit. Other measurement ranges are:

Range Value to select range

0.5 A values greater than 0.015A

15 mA values greater than 0.0005A up to 0.015A

0.5 mA values less than and up to 0.0005A

Window Functions

The dc source lets you select from two measurement window functions: Rectangular and Hanning. To

select a window function, use:

SENS:WIND: HANN | RECT

At power-on, the dc source measurement window is Rectangular. The Rectangular window calculates

average measurements without any signal conditioning. However, in the presence of periodic signals

such ac line ripple, a Rectangular window can introduce errors when calculating average measurements.

This can occur due to the last partial cycle of acquired data when a non-integral number of cycles of data

has been acquired. One way to overcome this limitation of the Rectangular window is to specify an

integral number of power line cycles with SENSe:SWEep:NPLCycles before making a measurement.

Another way of dealing with ac line ripple is to use a Hanning window.

The Hanning window applies a cos

weighting function to the data in the measurement buffer when

calculating average measurements. This attenuates the ac noise in the measurement window. The best

attenuation is achieved when at least three or more waveform cycles are in the measurement buffer.

Returning All Measurement Data From the Data Buffer

The MEASure:ARRay and FETCh:ARRay queries return all data values of the instantaneous voltage or

current buffer. No averaging is applied, only raw data is returned from the buffer. The commands are:

MEAS:ARR:CURR? (@<channel list>)

MEAS:ARR:VOLT? (@<channel list>)

Triggered Measurements

Use the measurement trigger system to synchronize the acquisition of measurements with either a BUS or

an external trigger. Use FETCh commands to return voltage or current information from the data

acquired by the measurement system. Briefly, to make a triggered measurement:

1 Select a sweep interval and sample size

2 Select the trigger source

3 Initiate the trigger system

4 Fetch the triggered measurements

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Agilent Technologies N3280A User Manual Page 45