XT2640 Operating Manual
13 July 2016
Page 108 of 187
20.2.3
DC
SUPPLIES
For the A RANGE setting –
For SD, AD or WD channels it will be as shown above. This will not be shown if using SH, AH or WH channels as no setting is
required.
The AUTO setting should be chosen as shown above; the text shown in each A RANGE button may have a different range
(LO) or (HI) indicated as that shows the actual range selected for the current being passed at that time.
For the FUND setting –
This must be set to NONE as shown above.
For the BANDWIDTH setting –
A 12kHz fixed frequency bandwidth limit setting should be set by using the USER choice and setting 12 kHz as the limit.
20.3
USING
THE
XT2640
TO
MONITOR
THE
SUPPLY
These requirements all require equipment being tested to meet performance requirements while being subjected to various levels,
frequencies, and disturbances to the supply being used to power it. In most cases you will use a power supply, possibly with some
other circuitry or instruments, to provide the required supply to the equipment.
The XT2640 can be used to monitor the supply to the equipment to ensure that most of these tests are being carried out properly
rather than just relying on the source producing the desired voltage, frequency and waveform.
For these tests the XT2640 is not making a measurement of the equipment, but is confirming the supply being used to power the
equipment. Whether the tests pass or not is not dependent on measurements made by the XT2640.
If you wish to record the measurements made, then it is recommended to either –
Save a graphical copy of the screen(s) to a USB Drive (see section 21.5)
Or, export all measurement results to a USB Drive (see section 21.5)
20.3.1
CONFIRMING
THE
VOLTAGE
AND
FREQUENCY
OF
THE
SUPPLY
The XT2640 may be used to confirm that the supply voltage and frequency are as required for many of the tests to be performed.
This is performed by using the POWER DATA screen which should be selected to display the results for the entire VPA (i.e. the entire
supply), showing the COUPLED data (so the AC+DC or the DC data is shown as configured for this supply), and showing the full
DETAILED information.
The primary data (shown in larger, gold colored text) for voltage and current shows the average of the phase voltages and currents
from the supply (for a 1‐phase or DC supply there is only a single phase).
The secondary data (shown in a smaller, white colored text) for voltage and current lists the voltages and currents from each phase
from the supply (for a 1‐phase or DC supply there is only a single phase). Also included in the secondary data for voltage are the
inter‐phase phase measurements.
The frequency shows the supply frequency (not shown for a DC supply).
20.3.2
CONFIRMING
THE
VOLTAGE
MODULATION
DEPTH
OF
THE
SUPPLY
The XT2640 may be used to confirm that the supply voltage modulation depth is as required for certain of the tests to be performed.
Note:
The bandwidth of the measurement may have a severe impact on the results obtained. The requirements do not generally
state any specific bandwidth for such a measurement, yet this is a measurement of peak values which are very dependent
on the measurement bandwidth by definition. You may wish to alter the MEAS CONFIG ‐ BANDWIDTH setting while
performing these tests to a lower value (e.g. 4kHz) to reduce the bandwidth of the measurement.
The XT2640 cannot confirm the frequency content of the modulation.
It is required that this value be measured over many measurement periods of the XT2640 (so giving a result for low frequency
modulation) this is achieved by using the POWER DATA screen configured to show each channel, and INRUSH data.
To use this screen follow the procedure described below –
