Test; Limits - Keithley 2002 User Manual

DCV, ohms, and DCI calibration requires the use of accurate
calibration equipment and is only intended to be performed
by qualified service personnel. Refer to the Model 2002 Cal-
ibration Manual to calibrate these functions.
AC-CAL: Use this menu item to perform the AC self-
calibration procedure.
The AC calibration constants generated by
this procedure are not permanently stored.
They are in effect only until the power is
turned off. To permanently store AC cali-
bration constants, refer to the Model 2002
Calibration Manual.
To perform an AC-only calibration, follow these steps:
1. The Model 2002 must be allowed to warm up for at least
one hour before calibration.
2. Disconnect all test leads or cables from the front and
rear INPUT and SENSE jacks.
3. Select POINT-CALS from the PERFORM CALIBRA-
TION menu.
4. Press ENTER to begin AC calibration, which takes
about six minutes to complete.
All keypresses are locked out when a cali-
bration step is in progress.
5. Once the process has successfully completed, the "AC
CAL COMPLETE" message is displayed, and you can
press ENTER or EXIT to return to a normal display.
DCV, OHMS and DCI: These menu items are used to cali-
brate DCV, ohms and DCI. The calibration procedures are
locked out to prevent accidental changing of calibration con-
stants. These calibration procedures should only be per-
formed by qualified service personnel. Refer to the Model
2002 Calibration Manual for details on performing point cal-
ibration for these functions.
CALIBRATION-DATES
Use this menu item to view or change the calibration dates.
Use the VIEW option of the menu to display the last
calibration date and the next calibration date. The DISPLAY-
AT-POWERUP option controls whether the next calibration
date is displayed during the power-up sequence.
NOTE
NOTE
The CHANGE option is locked; to enable it requires the
CAL switch to be pressed. The option allows you to change
the calibration date and next calibration date. Refer to the
Model 2002 Calibration Manual for instructions.

2.12.4 TEST

The SELF-TEST MENU is used as a diagnostic tool to iso-
late problems with the Model 2002. Information on using
these test procedures is included in the optional Model 2002
Repair Manual.

2.12.5 LIMITS

The LIMITS menu is used for the following operations:
• To set and control the limit values that determine the
PASS/FAIL and HI/LO status of subsequent measure-
ments.
• To set the digital output patterns that signify passing or
failing limit checks.
• To enable/disable a binning strobe signal on digital out-
put #4 for triggering a user-supplied device handler.
Since the logic sense of the digital output
lines is programmable (high-true or low-
true), this discussion of limits uses the log-
ical terms TRUE/FALSE and ON/OFF,
rather than HIGH and LOW.
There are two sets of limits, each with high and low limit val-
ues. You can program and enable one or both limit sets. With
both sets enabled, the values can overlap or one set can be
included in the other. The only restriction is that, within the
same set, the high limit must be greater than the low limit for
a valid test.
The limit test is performed after polynomial and percent
math operations. Unit prefixes are applied before the limit
test, for example:
• Low limit = -1.0, High limit = 1.0.
A 150mV reading equals 0.15V (PASS).
• Low limit = -1.0, High limit = 1.0.
A 0.6k reading equals 600 (FAIL).
Limit set #1 is available as a multiple display, which shows
a bar graph and a pass/fail indication for the measurements.
(Note: The PASS/FAIL indication is not available for ACV,
Front Panel Operation
NOTE
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