Keithley 6514, Instruction Manual

Page: 267 / 334

19-14 Calibration
Coulombs calibration
1. Connect the voltage calibrator and Model 5156 Calibration Standard to Model 6514
INPUT jack, as shown in Figure 19-4. Initially, make connections to the 1nF capacitor.
Also be sure to connect the link between SHIELD and CHASSIS.
2. Select Model 6514 coulombs function by pressing the Q key, and set the calibrator to
output volts.
3. Using the GRD key, disable Model 6514 guard mode.
4. Select Model 6514 20nC range, make sure the calibrator output is turned on and set the
output to 0V.
5. Press SHIFT then CAL, then press ENTER at the CAL: RUN prompt. The unit will
prompt for the positive full-scale calibration point:
+20nC CAL
6. Press ENTER. The unit will prompt for the positive full-scale calibration value:
20.0000nC
7. Set the calibrator voltage to +20.00000V. Compute the actual charge from the calibrator
voltage and actual capacitance value: Q = CV. Adjust Model 6514 display to agree with
that charge value, then press ENTER.
8. Model 6514 will prompt for the zero calibration point:
2nC ZERO
9. Press ENTER to complete zero calibration for the present range and then set the
calibrator to output 0V. Model 6514 will next prompt for the negative full-scale
calibration point:
-20nC CAL
RS232 DIGITAL I/O
PREAMP
250V PK
2V
OUTPUT
COMMON CHASSIS
120 FUSE LINE
630mA
LINE RATING
50, 60Hz
60 VA MAX
T
(SB)
100 VAC
120 VAC
315mAT
(SB)
220 VAC
240 VAC
INPUT 250V PK
IEEE-488
(CHANGE IEEE
WITH FRONT PANEL MENU)
TRIGGER LINK
!
! MADE IN
U.S.A.
V, GUARD
(PROGRAMMABLE)
OFF ON
GUARD
(FOLLOWS
INPUT)
(INTERNAL)
INPUT PREAMP
10K
PREAMP
OUT
2V
OUTPUT
COM
Model 6514 Electrometer
DC Voltage Calibrator
Triax Cable
100G Ω
100M Ω
10G Ω
1G Ω 1nF
100nF
OUTPUT
Connect
Cable Shield
to Output LO
Low-noise
Coax Cable
Note: Connect voltage calibrator
to appropriate capacitor.
Be sure shield LO to chassis
link is connected.
Model 5156 Calibration Standard
!
Charge Filter
Adapter
Figure 19-4
Connec-
tions for
coulombs