Keithley 172A Instruction Manual page 88

TABLE 6-7.
Full Range DC Calibration
INSTRUCTION MANUAL
Digital M"ltml*tar
Modala172A.
i73A
RANGE
3V
C.
L,I
300
v
30
v
29v
f 0.003% Il;i Xl0 GAIN (R612) 1
29.000
1200 v
IOOOV ?: 0.003% IKV ADJ (R214)
1000.0
AC Volta e Calibration.
I) Select AC V and MAN ranging.
2) Connect AC Calibrator (8) to the input terminals.
3) IV at IkHz Adjustment.
a. Select 3V range.
($:
Apply 1 Vat +0.04% at I kHz.
Adjust potentiometer RI04 (IV,
IkHz) for a 1.0000 ?I digit reading.
4) IOOV at 50kH.z Adjustment.
a. Select 300V range.
Ob.
Apply IOOV 20.1% at 50 kHz.
IO c*
Adjust variable capacitor C204 (IOOV, 50kHz) for a 100.00 i3 digit reading.
5) IV at 50kH.z Adjustment.
a.
Select 3V range
0::
Apply IVac iO.l% at 50kHz.
Adjust variable capacitor (C201 (IV, 50kHz) for a 1.0000 +3 digit reading.
d.
Ohms Calibration.
I) lOM0 Adjustment.
a. Select 0 (ohms) and MAN ranging.
b.
Select 30MQ HI range, 2 wire.
Connect a IOMn + 0.03% resistor between input upper terminals.
(Decade
resistor (C) may be used, it has 0.01% accuracy.)
OC'
12 d.
Adjust potentiometer RI15 (IOMR HI) for a 10.00 reading on the display.
0=.
Select 3OMa LO range; record the change in digits from IOMR HI range.
13 f. Adjust potentiometer R211 (IOMR LO) for IOMQ + l/IO A digits.
EXAMPLE: If IOMR LO was reading 9.850 (A digits = 150), adjust for a reading of
IO.015 (l/IO A digits = 15 digits).
6-12