Required Calibration Equipment; Environmental Conditions; Calibration Sequence; Input Offset Adjustment - Keithley 6512 Instruction Manual

ENABLED
DISABLED
Figure 7-1
Calibration jumper location

7.4.4 Required calibration equipment

The following items (one of each) are necessary to calibrate
the Model 6512:
• Keithley Model 263 Calibrator/Source.
• Fluke Model 343A DC Voltage Calibrator (190V;
±0.002% accuracy).
• Triax-to-Triax cable (supplied with 263).
• Keithley Model 6171 3-slot male to 2-lug female triax
adapter.
• Keithley Model CA-18-1 Dual Banana-to-Banana cable.
• Keithley Model CAP-31 protective cap/shield for the IN-
PUT connector.
If the Model 6512 is to be calibrated over
the IEEE-488 bus, computer equipment
will also be required. See Appendix D for
equipment and calibration program details.
POWER CALIBRATION
CONNECTOR JUMPER
MOTHER BOARD
FRONT OF INSTRUMENT
NOTE

7.4.5 Environmental conditions

Calibration should be performed under laboratory conditions
having an ambient temperature of 23° ±1°C and a relative
humidity of less than 70%. Both the Models 6512 and 263
should be allowed to warm up for at least two hours before
beginning calibration. If either instrument has been subject-
ed to extreme temperature or humidity, allow at least one ad-
ditional hour for the instrument to stabilize before beginning
the calibration procedure.
While rated accuracy of the Model 6512 is
achieved after the two-hour warm up peri-
od, input bias current may require addi-
tional time to come to its optimum level.
Allow two hours for input bias current to
settle to less than 10fA and eight hours to
less than 5fA.

7.4.6 Calibration sequence

Model 6512 calibration must be performed in the order giv-
en in the following paragraphs. The basic sequence is:
Manual adjustments:
1. Input offset adjustment (paragraph 7.4.7)
2. Input current adjustment (paragraph 7.4.8)
Digital calibration (front panel or IEEE-488 bus):
1. Amps calibration (paragraph 7.4.10)
2. Coulombs calibration (paragraph 7.4.11)
3. Volts calibration (paragraph 7.4.12)
4. Ohms calibration (paragraph 7.4.13)
In addition to the above sequence, the ranges for each func-
tion must be calibrated in the order given. Note that you
should never calibrate a range using a suppress or a zero cor-
rect value taken on a different range.

7.4.7 Input offset adjustment

Perform the following steps to null out any small offset in the
input amplifier:
1. Disconnect all input signals from the Model 6512.
Maintenance
NOTE
7-3