Section 8-Maintenance - Keithley 595 Instruction Manual

MAINTENANCE
8.5.5 Front Panel Calibration
The following information provides the general procedure
.for digitally calibrating the instrument from the front panel.
Thii is not the detailed calibration procedure and is only
intended to acquaint the technician with the general techni-
ques of~front panel calibration. The detailed calibration pro-
cedure, which includes the manual adjustments, starts at
paragraph 8.5.%
With the instrument in the calibration program (see para-
graph 8.5.8), front panel (digital) calibration is performed
as follows:
1. Select the function and range to be calibrated.
2.~
For current calibration, zero correct the instrument. Zero
correction is not necessary for capacitance calibration.
3. Set calibrator to OV or cap the input for capacitances
c&b&ion. Disable ZERO CHECK and after allowing the
readiig to settle, press SUPPRESS.
4. Aoplv the calibration source to the instrument.
5.
6.
z
U$g the voltage source ADJUST buttons, set the dis-
play to agree with the actnal calibration source value. For
example, for a calibration source value 1.9oOOfi, set the
display to read 1.9800 pA. (Note that the decimal points
in the exponent annunciators indicate that the calibra-
tion program is selected).
Repeats steps 1 through 5 for each function/range to be
calibrated.
To store the calibration points in memory, press the
MENU button.
A. With the calibration iumner in the enable wsition.
B.
the "Stor" message' w& be displayed b&fly in-
dicating that the calibration points have been stored
into permanent (NVRAM) memory. The instrument
will then exit the calibration program.
With the calibration jumper in the disable position,
the "out" message will be displayed briefly and the
instrument will exit the calibration program. The
bliig exponent decimal points indicate that the
calibration points have been stored in temporary
(RAM) memory These temporary calibration points
will be lost when the instrument is turned off. The
previous permanent caliiation points will prevail
when the instrument is again turned on.
Note: The calibration program (CAL) remains on the pro-
gram menu as long as the instrument remains on. This
allows the technician to select the calibration program
without turning off the instrumentand subsequently los-
ing temporary calibration points.
8.5.6 IEEE-488 Bus Calibration
The following information provides the general procedure
for entering calibration points over the IEEE-488 bus. This
is not the detailed calibration procedure and is only intend-
ed to acquaint the technician with the general techniques
of IEEE-488 bus calibration. The detailed calibration pro-
cedure, which includes the manual adjustments, starts at
paragraph 8.5%
IEEE-488 bus calibration is similar to front panel calibra-
tion except that calibration values are transmitted over the
bus instead of being entered from the front panel. Also,
a separate command is included to perform permanent
storage. By co~mbinmg appropriate IEEE-488 compatible
calibration equipment with a suitable test program, digital
calibration of the Model 595 could be performed on an
automated basis.
Calibration points are sent to the Model 595 over the
IEEE-488 bus as follows:
1. Program the desired range over the bus. For emple,
to select the 2nA range and current function, send
FlR3X.
2.
For current calibration, zero correct the instrument by
sending Z2X. Zero correction is not necessary for
capacitance calibration.
3. Set calibrator to W or cap the input for capacitance
calibration. Disable ZERO CHECK snd after aRowing the
reading to settle, enable SUPPRESS.
4. Apply the calibration source to the input jack.
5. Send the required calibration value preceded by the A
command letter. For example, to calibrate the %A range
at the 19nA calibration point, send A19E-09X. Note that
the exponent decimal points will blink indicating that
temporary storage has ocmred.
6. Repeat steps l-5 for the mmaining ranges and functions.
7. After all points have been calibrated, send Jl9X to per-
manently store calibration constants. Note that even
though it is most practical to send the storage command
@X) after all Cal&ration comman ds have been sent, the
storage command can be sent after each calibration
command.
NOTE
Permanent storage of calibration constants wiIl not
take place if the calibration jmnper is in the disabl-
ed position. See paragraph 85.4 for details.
8-S