Keithley 2002, Руководство по калибровке

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Calibration
2-24
Step 10: Save calibration constants
Calibration is now complete, so you can store the calibration
constants in EEROM by sending the following command:
:CAL:PROT:SAVE
Step 11: Lock out calibration
To lock out further calibration, send the following command
after completing the calibration procedure:
:CAL:PROT:LOCK
2.11 Single-point calibration
Normally, the complete comprehensive (or low-level, if nec-
essary) calibration procedure should be performed to ensure
that the entire instrument is properly calibrated. In some
instances, however, it may be desirable to calibrate only cer-
tain ranges and functions. For those cases, a single-point cal-
ibration feature is included in the Model 2002.
The following paragraphs give an overview of performing
single-point calibration both from the front panel and over
the IEEE-488 bus. For details on specific procedures, test
equipment connections, and IEEE-488 bus commands, refer
to paragraphs 2.6 through 2.10 of this section.
Remember that calibration must be unlocked (except for AC
only user calibration). To unlock point calibration, press in
on the CAL switch.
2.11.1 Front panel single-point calibration
Front panel single-point calibration can be performed by us-
ing the POINT-CALS selection in the CALIBRATION
menu. You will then be prompted as to which function to cal-
ibrate: DCV, DCI, or OHMS. If you select DCI or OHMS,
you will also be able to select the range to calibrate, and will
then be prompted to apply the appropriate calibration signal.
See paragraph 2.8 for details on comprehensive calibration
steps.
If you enable low-level calibration by holding in the CAL
switch while turning on the power, the LL-CAL (low-level
calibration) selection will also appear in the POINT-CALS
menu. You can then calibrate a specific low-level point (see
paragraph 2.10 for details).
Example
Assume that you wish to calibrate the 2k
Ω
range. Follow the
steps below to do so.
1. Turn on the Model 2002, and allow the instrument to
warm up for at least four hours before performing
calibration.
2. Press in on the front panel CAL switch to unlock
calibration.
3. Press the MENU key. The instrument will display the
following menu:
MAIN MENU
SAVESETUP GPIB CALIBRATION
4. Select CALIBRATION, then press ENTER. The follow-
ing menu will be displayed:
PERFORM CALIBRATION
COMPREHENSIVE POINT-CALS
5. Select POINT-CALS, then press ENTER. The Model
2002 will prompt you to select the function:
POINT CALIBRATION
AC-CAL DCV OHMS DCI
6. Select OHMS, then press ENTER. The unit will prompt
you to choose the range:
CHOOSE OHMS RANGE
20
Ω
200
Ω
2k
Ω
20k
Ω
200k
Ω
7. Select 2k
Ω
, then press ENTER. The unit will prompt
you to apply the appropriate calibration signal:
CONNECT 2K
Ω
4W
8. Connect the 2k
Ω
(or closest available value) to the
INPUT and SENSE jacks using the 4-wire connections
shown in Figure 2-1. Press ENTER.
9. Use the range and cursor keys to set the displayed resis-
tance value to the exact calibration resistance, then press
ENTER.
10. Repeat the above steps for other calibration points, if
desired.
11. If desired, select CALIBRATION-DATES in the cali-
bration menu, then set the calibration date and due date
accordingly.
12. Press EXIT as necessary to return to normal display.
Valid calibration constants will be saved, and calibration
will be locked out.
2.11.2 IEEE-488 bus single-point calibration
To perform IEEE-488 bus single-point calibration, simply
connect the appropriate signal, then send the corresponding
calibration command. (See Table 2-4 for a summary of com-