Warm-Up Period; Line Power; Calibration Lock; Comprehensive Calibration Lock - Keithley 2001 Calibration Manual

Calibration
2.3

Warm-up period

The Model 2001 must be allowed to warm up for at least one
hour before calibration. If the instrument has been subjected
to temperature extremes (outside the range stated in para-
graph 2.2), allow additional time for internal temperatures to
stabilize. Typically, it takes one additional hour to stabilize a
unit that is 10°C (18°F) outside the specified temperature
range.
The calibration equipment should also be allowed to warm
up for the minimum period specified by the manufacturer.
2.4

Line power

The Model 2001 should be calibrated while operating from a
line voltage in the range of 90-134V or 180-250V at 50, 60,
or 400Hz.
2.5

Calibration lock

Calibration can be unlocked by pressing in on the front panel
CAL switch. Remove the sticker that covers the CAL switch
access hole before calibration. Replace the sticker after com-
pleting calibration.

2.5.1 Comprehensive calibration lock

Before performing comprehensive calibration, you must first
unlock calibration by momentarily pressing in on the re-
cessed CAL switch. The instrument will display the follow-
ing message:
CALIBRATION UNLOCKED
Comprehensive cal can now be performed
If you attempt comprehensive or low-level calibration with-
out performing the unlocking procedure, the following mes-
sage will be displayed:
CALIBRATION LOCKED
Press the CAL switch to unlock.
Note that it is not necessary to unlock calibration for the AC-
only self-calibration procedure.
If the CAL switch is pressed with calibration already un-
locked, the following message will be displayed:
CAL ALREADY UNLOCKED
Cycle Power to relock cal switch.
2-2

2.5.2 Low-level calibration lock

To unlock low-level calibration, press in and hold the CAL
switch while turning on the power. Low-level calibration can
then be performed.
Do not unlock low-level calibration unless
you have the appropriate equipment and
intend to perform low-level calibration.
See paragraph 2.10 for low-level calibra-
tion details.

2.5.3 IEEE-488 bus calibration lock status

You can determine the status of either calibration lock over
the bus by using the appropriate query. To determine com-
prehensive calibration lock status, send the following query:
:CAL:PROT:SWIT?
The instrument will respond with the calibration lock status:
0: comprehensive calibration locked
1: comprehensive calibration unlocked
To determine the status of the low-level calibration lock,
send the following query:
:CAL:PROT:LLEV:SWIT?
Responses to this lock query are:
0: low-level calibration locked
1: low-level calibration unlocked
Refer to paragraph 2.6.1 below and Section 3 for more de-
tails on calibration commands.
2.6 IEEE-488 bus calibration commands
and program

2.6.1 Calibration commands

Table 2-1 summarizes calibration commands used to cali-
brate the instrument over the IEEE-488 bus (GPIB). For a
complete description of calibration commands refer to Sec-
tion 3.
NOTE