Keithley 2700, Service Manual

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2-2 Calibration
Introduction
Use the procedures in this section to calibrate the Model 2700. Calibration procedures
include:
• Comprehensive calibration: Usually the only calibration required in the field.
• Manufacturing calibration: Usually only performed at the factory (unless the unit has
been repaired).
• Model 7700 calibration: Covers calibration procedures specific to Model 7700 cards.
WARNING The information in this section is intended only for qualified service per-
sonnel. Do not attempt these procedures unless you are qualified to do so.
All the procedures require accurate calibration equipment to supply precise DC and AC volt-
ages, DC and AC currents, and resistance values. Comprehensive calibration can be performed
any time by an operator either from the front panel, or by using the SCPI commands sent either
over the IEEE-488 bus or the RS-232 port. DC-only and AC-only calibration may be performed
individually, if desired.
Environmental conditions
Conduct the calibration procedures in a location that has:
• An ambient temperature of 18° to 28°C (65° to 82°F)
• A relative humidity of less than 80% unless otherwise noted
Warm-up period
Allow the Model 2700 Multimeter/Data Acquisition system to warm up for at least two
hours before performing calibration.
If the instrument has been subjected to temperature extremes (those outside the ranges stated
above) allow extra time for the instrument’s internal temperature to stabilize. Typically, allow
one extra hour to stabilize a unit that is 10°C (18°F) outside the specified temperature range.
Also, allow the test equipment to warm up for the minimum time specified by the
manufacturer.
Line power
The Model 2700 requires a line voltage of 100V/120V/220V/240V, ±10% and a line fre-
quency of 45Hz to 66Hz. Note that the line frequency is automatically sensed at power-up, but
the line voltage must be manually set to either 100V/120V or 220V/240V as described in
Section 3.