Keithley 2700, Service Manual

Page: 29 / 174

Performance Verification 1-13
Verifying resistance
Check resistance by connecting accurate resistance values to the Model 2700 and verifying
that its resistance readings are within the specified limits.
CAUTION Do not apply more than 1000V peak between front terminals INPUT HI
and LO or more than 350V peak between SENSE HI and LO, or instru-
ment damage could occur.
Follow these steps to verify resistance accuracy:
1. Using shielded, Teflon-insulated or equivalent cables in a 4-wire configuration, connect
the Model 2700 INPUT and SENSE jacks to the calibrator as shown in
Figure 1-5 . Be
sure the INPUTS switch is in the FRONT position.
Figure 1-5
Connections for Model 2700 resistance verification (100
Ω
to 10M
Ω
ranges)
2. Set the calibrator for 4-wire resistance with external sense on.
3. Select the Model 2700 4-wire resistance function by pressing the
Ω
4 key, then choose
the SLOW integration rate with the RATE key.
4. Set the Model 2700 for the 100
Ω
range, and make sure the FILTER is on. Enable
OCOMP (offset-compensated ohms) for 100
Ω
range verification. (Press SHIFT then
OCOMP.)
5. Recalculate reading limits based on actual calibrator resistance values.
Output
LO Input
LO
Input
HI
Resistance Calibrator
Sense HI
Sense LO
Output
HI
Sense HI
Sense LO
Note: Use shielded low-thermal cables to
minimize noise. Enable or disable
calibrator external sense as indicated
in procedure.
Model 2700
Model 2700 Multimeter / Data Acquisition System
RANGE
!
F
500V
PEAK
FRONT/REAR
3A 250V
AMPS
HI
INPUT
LO
SENSE
Ω
4 WIRE
INPUTS
350V
PEAK
1000V
PEAK
AUTO
SHIFT
LOCAL
POWER
RANGE R
EXIT ENTER
DIGITS RATE
REL FILTER
TRIG
EX TRIG STORE RECALL
OPEN
DCV DCI
MATH O U T P U T
RATIO
ACV ACI
Ω
2
Ω
4 FREQ TEMP
CH AVG
CONT
PERIOD SENSOR
LIMITS ON/OFF DELAY HOLD
SAVE SETUP CONFIG HALT
TYPE
LSYNC TEST
MONITOR
STEP SCAN
OCOMP
CH-OFF CARD
CLOSE
Integra Series
RS-232 GPIB