APPLICATIONS
storage of calibration constants will not take place.
However, temporary calibration values may be entered
and used even if NVRAM
calibration storage is disabled.
Note, however, that calibration parameters will be lost
once power is turned off unless they are stored in
NVRAM.
The calibration jumper location and the disabled/enabled
positions are indicated in Figure 5-2.
WARNING
Turn
off the instrument and disconnect the
line
cord
before removing the top cover to reposi-
tion the calibration jumper.
Figure 5-2. Calibration Jumper Location
(Model 617)
5.3.2 Required Equipment
The following items (one of each) are necessary to calibrate
the Model 617:
1. Keithley Model 263 Calibrator/Source.
2. Keithley Model 196 System DMM ( f 0.015%).
l
3. Fluke Model 343A DC Voltage Calibrator (190V;
4. Triax-to-Triax cable (supplied with 263).
5. Keithley Model CA-18-l Dual Banana-to-Banana cable.
NOTE: The following additional equipment will be
necessary if calibration is to be performed over the
IEEE-488 bus.
6. HP 85 Computer equipped with HP 82937 GPIB Inter-
face and I/O ROM.
7. Keithley Model 7008 IEEE cable.
*Accuracy requirement of calibration equipment.
5.3.3 Environmental Conditions
Calibration should be performed under laboratory condi-
tions having an ambient temperature of 23 f 1°C and a
relative humidity of less than 70%. With both the Models
617 and 263 on, allow them to warm up for one hour. If
either instrument has been subjected to extreme tempera-
ture or humidity, allow at least one additional hour for
the instrument to stabilize before beginning the calibra-
tion procedure.
NOTE
While rated accuracy of the Model 617 is achiev-
ed after the two hour warm UD ueriod. inuut bias
1 i
current may require additional tune 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.
5.3.4 Calibration Sequence
Model 617 calibration must be performed in the order
given in the following paragraphs, with the exception of
the voltage source calibration, which can be done at any
time. The basic sequence is:
5-5
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