Perform a Source Power Cal using COM

This program can be run in either Visual Basic 6 or as a VBScript program. The PNA can run *.vbs programs as macros.

This program demonstrates:

Learn more about Power Calibrations

See an example that Uploads a Source Power Cal

 See Other COM Example Programs

To run this program, you need:

Note: If your power meter is other than these, you can create your own Power Meter Driver using our template.

To make this program work in VBS, save the following code in a text editor file such as Notepad and save as *.vbs.

To make this program work in Visual Basic 6:

  1. Create a new project

  2. Click Project, Add New Module, click Open.

  3. Paste the following code into the code window.

  4. Delete the first two lines (comment and Main)

  5. Click Project, Properties. Under Startup Object, select Sub Main

  6. Click Project, References, and select the Keysight PNA Series Type Library.

' Run the Main subroutine
Public Sub Main()
Dim PNA, chan, pwrcal                               ' PNA COM objects
Const naPowerMeter = 0, naPowerMeterAndReceiver = 1 ' enum NASourcePowerCalMethod
Const naPowerSensor_A = 0                           ' enum NAPowerAcquisitionDevice
Const naCorrectionValues = 0                        ' enum NASourcePowerCalBuffer
Const port = 2                                      ' PNA port #2 as source port
Const offset = 0                                    ' cal power offset value
Const bDisplay = True                               ' whether to display data during acquire
Dim stimulus, calvalues, strResult

' Instantiate our PNA COM objects

Set PNA = CreateObject("AgilentPNA835x.Application")
Set chan = PNA.Channels(1)
Set pwrcal = PNA.SourcePowerCalibrator

' Set the number of sweep points to 21 on Channel 1.

chan.NumberOfPoints = 21

' Specify the GPIB address of the power meter
' that will be used in performing the calibration.

pwrcal.PowerMeterGPIBAddress = 13

' Turn use of the loss table OFF (this assumes there is
' virtually no loss in the RF path to the power sensor
' due to a splitter, coupler or adapter).

pwrcal.UsePowerLossSegments = False

' Turn frequency checking OFF (so one power sensor is used for the entire cal
' acquisition sweep regardless of frequency span).

pwrcal.UsePowerSensorFrequencyLimits = False

' Specify a nominal power accuracy tolerance (IterationsTolerance) in dB for the
' calibration, and the maximum number of iterations to adjust power at each point,
' attempting to achieve within tolerance of the desired power.  If at any stimulus
' point the power fails to reach within the set tolerance of the desired power
' after the maximum number of iterations, the power at that point will be set to the
' value determined by the last iteration (the Source Power Cal dialog box will
' indicate the FAIL, but we can still apply the cal if desired when it's complete).
' Each iteration is based upon a SETTLED power reading (see comments preceding the
' next two properties below).

pwrcal.IterationsTolerance = 0.1
pwrcal.MaximumIterationsPerPoint = 3

' The worst-case window of power uncertainty (for a calibration which meets
' tolerance) is the sum of the iteration tolerance and the power meter settling
' tolerance (which is described below).
' At each stimulus point, the PNA takes power meter readings and determines when
' they have settled by comparing the magnitude difference between consecutive
' readings versus a nominal dB tolerance limit (ReadingsTolerance) on that magnitude
' difference.  When consecutive readings are within tolerance of each other, or
' if they are not within tolerance but we've taken a maximum number of readings
' (ReadingsPerPoint), the PNA does a weighted average of the readings taken at that
' stimulus point and that is considered our settled power reading.

pwrcal.ReadingsTolerance = 0.1
pwrcal.ReadingsPerPoint = 5

' Setup of information pertaining to this specific cal acquisition.  Includes the
' method (type of devices) that will be used to perform the cal -- choose either
' naPowerMeter or naPowerMeterAndReceiver.  naPowerMeterAndReceiver uses the power
' meter for the first iteration of each point and the PNA's reference receiver for
' subsequent iterations, so is much faster than using power meter only  naPowerMeter).
' But the power meter accounts for compression when calibrating at the output of an
' active device, whereas the reference receiver cannot unless it is coupled to the
' cal reference plane (on a PNA which allows direct access to the receivers).
' 'offset' specifies if the cal power level is offset (positive value for a gain,
' negative value for a loss) from the PNA port power setting on the channel when
' no source power cal is active.  This is to account for components between the PNA
' test port and cal reference plane.  In this example, we will calibrate at the PNA
' test port, so there is no offset (it is zero).
' 'bDisplay' indicates whether to display the source power cal dialog during the
' source power cal acquisition (the dialog will chart the corrected power readings).

pwrcal.SetCalInfo2 naPowerMeter, chan.channelNumber, port, offset, bDisplay

' Perform synchronous source power cal acquisition sweep using the sensor attached
' to Channel A of the power meter.  This assumes that the power sensor is already
' connected to Port 2 of the PNA.

pwrcal.AcquirePowerReadings naPowerSensor_A, True

' Conclude the calibration.  This applies the cal data to PNA channel memory,
' and turns the correction ON for Port 2 on Channel 1, but does NOT save the
' calibration.


' At this point, if you choose to save the instrument state as a ".CST" file,
' the calibration will be saved with the instrument state in that file.
' Read the stimulus values from Channel 1.

stimulus = chan.GetXAxisValues

' Read the source power correction data.

calvalues = chan.getSourcePowerCalDataEx(naCorrectionValues, port)

' Print the data using a message box (here, Chr returns the ASCII characters
' for Tab (9) and Linefeed (10)).

strResult = "Stimulus" & Chr(9) & Chr(9) & "Cal Value" & Chr(10)
For i = 0 To UBound(stimulus)
strResult = strResult & stimulus(i) & Chr(9) & calvalues(i) & Chr(10)
MsgBox strResult
End Sub