Running the Compensation Process

• Setting Compensation Kit Values

• Measuring Data for Calculating Compensation Coefficients

• Calculating Compensation Coefficients and Turning ON/OFF Compensation

• Preventing Operational Errors When Measuring Data for Calculating

• Saving or Recalling Compensated State (Retrieving or Writing Compensation)

Other topics about Preparing for Accurate Measurement

• You must turn ON the calibration function before using it. In other words, when the calibration function is OFF, you cannot perform any of the compensation related operations, including measuring the data for calculating the compensation coefficients, calculating the compensation coefficients, turning ON or OFF the compensation function, and retrieving or setting the compensation coefficients. However, you can configure the compensation kit even when the calibration function is OFF.

Setting Compensation Kit Values

You can either use the E4982A's predefined compensation kit values or directly enter other compensation kit values. To choose how the compensation kit values are defined, use the following command:

• :CORR2:CKIT

If you opt to enter the values, you need to specify how the compensation kit itself is defined and then enter the definitions.

Choosing definition method (Fixed or Point-by-Point)

• :CORR2:CKIT:LIST

Entering definitions

To define the OPEN and SHORT standards, use the commands listed in the following table:

Measuring Data for Calculating Compensation Coefficients

To measure the data for calculating the compensation coefficients, use the following command:

• :CORR2:COLL

The command shown above measures the data for calculating the compensation coefficients for both impedance and Rdc measurements. If you want to obtain the data for either impedance or Rdc measurement alone, use one of the following commands instead:

• :CORR2:COLL:RF

• :CORR2:COLL:DC

• Issuing the :CORR2:COLL, :CORR2:COLL:RF, or :CORR2:COLL:DC command does not trigger the instrument to begin measuring the data. This means that if the trigger source is not Internal trigger, you must trigger the instrument after issuing the command.

To define the OPEN and SHORT compensation standards using the commands described so far, follow these steps:

If you use the same standards for both impedance and Rdc measurements or you omit Rdc measurement:

1. Connect the OPEN standard and then issue the :CORR2:COLL command, which designates “STAN1” as the parameter. If the trigger source is not Internal trigger, you must trigger the instrument after issuing the command. This applies to step 2 as well.

2. Connect the SHORT standard and then issue the :CORR2:COLL command, which designates “STAN2” as the parameter.

3. Issue the :CORR2:COLL:SAVE command.

If you use different standards for impedance and Rdc measurements:

1. Connect the OPEN standard for impedance measurement and then issue the :CORR2:COLL or :CORR2:COLL:RF command, which designates “STAN1” as the parameter. If the trigger source is not Internal trigger, you must trigger the instrument after issuing the command. This applies to steps 2 through 4 as well.

2. Connect the SHORT standard for impedance measurement and then issue the :CORR2:COLL or :CORR2:COLL:RF command, which designates “STAN2” as the parameter.

3. Connect the OPEN standard for Rdc measurement and then issue the :CORR2:COLL:DC command, which designates “STAN1” as the parameter.

4. Connect the SHORT standard for Rdc measurement and then issue the :CORR2:COLL:DC command, which designates “STAN2” as the parameter.

5. Issue the :CORR2:COLL:SAVE command.

Calculating Compensation Coefficients and Turning ON/OFF Compensation

After measuring the data for calculating the compensation coefficients, issue the following commands to calculate the compensation coefficients and turn on the compensation function:

*1. Issue the command, which designates "ON" (or '1") as the parameter.

When the OPEN compensation function is currently ON, you can issue the :CORR2:COLL:OPEN command by specifying “OFF” (or “0”) as the parameter to turn OFF the OPEN compensation function.

Similarly, when the SHORT compensation function is currently ON, you can issue the :CORR2:COLL:SHOR command by specifying “OFF” (or “0”) as the parameter to turn OFF the SHORT compensation function.

Preventing Operational Errors When Measuring Data for Calculating

To retrieve each standard’s measurement data for calculating the compensation coefficients for Rdc measurement, use the following command:

• :DATA:RCMD{1-2}?

Since this command returns the Rdc measurement value (without compensation) for each of the OPEN and SHORT standards, you can check whether this value is normal to prevent operational errors (such as connecting the wrong standard) that may arise when measuring the data.

When you validate the Rdc measurement results returned by the command :DATA:RCMD{1-2}?, you should use the absolute value for the same reasons as shown in Preventing operational errors when measuring data for calculating calibration coefficients.

The measurement data of the OPEN and SHORT standards used for calculating the compensation coefficients for impedance measurement are stored in the calibration data array (see Compensation Data Arrays). You can retrieve this data with the following command:

• :DATA:CMD{1-2}?

This command returns RF measurement data without compensation, which require more complex handling than Rdc values.To detect operational errors that may have occurred while measuring the compensation data, it is best to use Rdc values instead.

Saving or Recalling Compensated State (Retrieving or Writing Compensation)

You can retrieve the compensation coefficients and save them to a file. Later, you can retrieve the compensation coefficients from the file and load them into the E4982A to restore the compensated state at the time you saved the file.

The compensation coefficients for impedance measurement are stored in the compensation coefficient array (see Compensation Data Arrays). To read or write the compensation coefficient array, use the following command:

• :DATA:CMP{1-3}

To read or write the compensation coefficients for Rdc measurement, use the following command:

• :DATA:RCMP{1-3}

• When setting compensation coefficients, note these precautions:
  1. To ensure that the instrument will provide correct measurement results, you must configure the instrument to use the same measurement points (point setup table settings) as when you obtained measurement data for compensation and turn on the calibration function before you set the coefficients.
  2. You must turn on the compensation function before setting the compensation coefficients. To do so, follow the steps shown in Measuring data for calculating compensation coefficients. This procedure includes only measuring tentative data, and does not require you to connect the standard before issuing the data measurement command.

Sample Program

See Calibration and Compensation.