Agilent Technologies 4155C, User Manual

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3-18 Agilent 4155C/4156C VXIplug&play Driver User’s Guide, Edition 4
Programming Examples for Visual Basic Users
Synchronous Sweep Measurements
Synchronous Sweep Measurements
This section explains example subprograms that enable/disable measurement
channels (perform_meas), perform staircase sweep measurement (sweep_meas),
and save measurement result data into a file (save_data). This example measures
MOSFET Id-Vg characteristics. The subprogram uses the synchronous sweep
source.
Table 3-5 Synchronous Sweep Measurement Example
Sub perform_meas(vi As Long, ret As Long) ’1
Dim m(4) As Long ’SMU port numbers ’3
m(0) = 1 ’SMU1: drain
m(1) = 2 ’SMU2: gate
m(2) = 3 ’SMU3: source
m(3) = 4 ’SMU4: substrate
ret = hp4156b_setSwitch(vi, m(3), 1) ’9
ret = hp4156b_setSwitch(vi, m(2), 1)
ret = hp4156b_setSwitch(vi, m(1), 1)
ret = hp4156b_setSwitch(vi, m(0), 1)
check_err vi, ret
’13
sweep_meas vi, ret, m() ’15
ret = hp4156b_setSwitch(vi, hp4156b_CH_ALL, 0) ’17
check_err vi, ret
End Sub ’20
Line Description
1 Beginning of the perform_meas subprogram.
3 to 7 Declares variables, and defines the value.
9 to 12 Enables measurement channels.
15 Calls the sweep_meas subprogram (next page) to perform
staircase sweep measurement.
17 Disables measurement channels.
13 and 18 Calls the check_err subprogram (shown in Table 3-1) to check if
an error status is returned for the previous line.
20 End of the perform_meas subprogram.