Specifications

74 Using the DMM and ARB Chapter 4
Note Use the Watch Window to determine the amount of segment memory used
by the swept sine waveforms.
Generating Custom
Waveforms
Custom waveforms can be generated using the “Arb_Dl_Waveform_Data”
action and or the “Arb_Dl_Custom_Waveform” actions.
Downloading a Data Type Custom Waveform
The “Arb_Dl_Waveform_Data” action uses a ‘Waveform’ type array
variable called “Waveform” to generate a custom waveform. The variable
stores both the segments of the waveform (i.e., amplitude) and the time all
segments are to be executed (i.e., waveform frequency).
Figure 4-5 shows the data used to generate the waveform shown in the
bottom part of the figure. The segment data of the waveform is stored in the
array part of the “Waveform” parameter. (You can view the resultant
waveform by clicking on the “View Waveform” button, as shown in Figure
4-5.)
How to download custom data type waveforms is shown in testplan
‘
arbcustom_data.tpa’. The waveform is a 1 kHz (1 mS), 2 V peak ramp,
consisting of 21 segments. A review of the testplan is below.
Test Group/Test/Action Name Description
testgroup download custom waveform Downloads a user generated data type custom waveform.
Switching Connect Arb channel 1 output to ABus1 and UUT Common.
test setup Arb Setup arb output circuitry.
arbConfOutControls Configures Arb’s output circuitry.
arbSet Sends setup data to Arb.
test download custom waveforms Downloads custom waveforms to Arb.
Arb_Dl_Waveform_Data Downloads data type waveform into Arb. The waveform data is the data
stored into the ‘Waveform’ variable (see Figure 4-5 for typical waveform
data).
The ‘waveform_name’ parameter is set to “wave1” to give the
downloaded waveform that name.
The maximum value in the ‘Waveform’ array variable is “2.0000000000”
which makes the peak Waveform voltage 2.0 V.
The Star and /Stop values in the ‘Waveform’ array are set to
“0.0000000000” and “.0010000000”, respectively. This outputs a 1 kHz
waveform (Stop - Start = .0010000000 - 0.0000000000 = 1 mS or 1 kHz).
test output custom waveform This test executes the downloaded waveform. Although the Arb outputs the
waveform from the previous test (after ‘arbinitiate’ in “test download custom
waveform”), this test is to show that the waveform can be selected in any
part of the testplan. The Arb normally outputs the last downloaded
waveform, whether a custom waveform or a standard waveform, but can
output a different waveform in any part of the testplan using the action in
this test.
arbInitiate Initialize the Arb to output the waveform. Start outputting the waveform.
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