Tektronix Keithley 2268 Series, Справочное руководство

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Series 2268 850 Watt DC Power Supplies Reference Manual Calibration and Troubleshooting
2268S-901-01 Rev. A / January 2015 197
CALIBRATING THE OUTPUT VOLTAGE
Gain calibration of the power supply has the greatest effect on the accuracy in the high
voltage range. Offset calibration has the greatest effect on accuracy of the power supply at
low voltages. The same calibration command is used for the gain and offset calibrations. The
type of calibration is determined internally by the instrument depending on if the set point is
above 10% of the maximum output voltage value or not. If it is above 10% of the maximum
voltage, the calibration is a gain calibration; if is below 10%, it is an offset calibration.
Gain Calibration
To perform gain calibration:
1. Disconnect the power supply from the load.
2. Connect the output terminals to a precision voltmeter.
3. Turn both the power supply and the voltmeter to On.
4. Set the current set point to maximum. Set the supply output to 90% of the nominal
voltage level.
5. Turn on the output power.
6. Read the voltage value on voltmeter display.
7. Type the SCPI command with voltage value as parameter “data”.
For example, type :CAL:OUTP 138.3 if you had a model 150-5.6 calibrating with the
voltage set point set to 135 V and the voltmeter was reading 138.3 volts.
Offset Calibration
To perform offset calibration:
1. After performing gain calibration, set the programmed voltage 10% from nominal.
2. Read the voltage value on the voltmeter display.
3. Type the SCPI command with voltage value as parameter “data”.
For example, you would type : CAL: OUT P1 2 . 3 if you had a model 150-5.6
calibration with the voltage set point set to 10V and the voltmeter was reading 12.3
volts.
After performing offset calibration, it is recommended that you repeat gain calibration.
Important: For best results, both calibrations may be repeated several times.
The SCPI Command (s) for these instructions are:
[:]CALibration[<channel>]:OUTPut{:VOLTage]{<voltmeter reading in volts>}