Current Calibration - Keithley 595 Instruction Manual

MAlNTENhNCE
Table 8-4. Current Calibration
595
CaIibration T&t DC Calibrator
595 Calibration
IEEE-488 Bus
Range CutTent Setup Filter Resistor Value* Voltage Point Command
2OOpA 190.00 pA Figure 8-6 2 (10 Gil) ~ 190.00 pA A19OE-12x
201~4 19.000 nA Figure 8-6 2 (100MQ) -
gzi
19.000 IL4 A19E-9X
2.~4
1.9000 PA Figure 8-7
E
lO.OOMa 19.oooov 1.9000 f&4 A1.9E-6X
20 pA 19.000 pA Figure 8-7 l.OOOMQ 19.OOoOV 19.000 &A A19E-6X
200 pA 190.00 pA Figure 8-7 0 lOO.OOkR 19.000w 190.00 PA A190E-6X
*Values in parenthesis are nominal values. See text for methods to determine these values.
8.514 Current Calibration
5. S&t the calibrator to output OV
6. Disable ZERO CHECK, allow the reading to settle and
Digital calibration of the current function should be per-
enable SUPPRESS in that order.
formed on these particular ranges~ in the following order:
7. Set the calibrator to output the voltage listed in Table
2OOpA, 20nA, 2fi, 2Ofi, and 2006 range% Once these
8-4 for the 2OOpA range.
ranges are calibrated, ~the remaining current ranges are
automatically calibrated.
8. Perform ones of the following operations to digitally
enter the calibration value:
A. From the front uanel. adiust the disDlav to read
Ticin~ T=hlz= R-d a< s oriide nmrwrl .a< fnllowc~
---.. --I__ - _ -- -o-I-, =~----- -- _-._ -..- _
1. Using the teraohmmeter, accurately measure the values
of the lOG0 and lOOMa resistors. Record the values in
the first and second lines of aable 8-4. Using these
values, calculate each calibration voltage as follows:
E=IxR
Where I is the calibration current and R is the measured
resistance value. Record the calculated calibrator
voltages in the table. For -pie, if the ach~al resistance
value of the 1OGQ resistor is lO.lGQ, the calibrator
voltage value would be 1.919V.
NOTE
Do not touch the body of the resistors. Contamina-
tion could give erroneous results.
2.Place the instrument in the current function, 2OOpA
range, and select FILTER 2. Make sure the calibration
probmm is selected if calibration is to be done from the
front panel.
3. Zero con'ect the instrument by enabling ZERO CHECK
and performing CORRect in thai order.
4. Connect the DC calibrator and 1OGQ resistor to the
Model 595, as shown in Figure 8-6. Note that the resistor
is to be placed in a shielded enclosure, as shown on the
diagram. (See Figure 8-l for recommended shield).
19O.OOpA using tI& yol&ge'source ADJCS? buttons.
B;~ lover the IEEE~488 bus,~~send A190ErlW.~~
9. Enable ZERO CHECK, disable SUPPRESS, and set the
calibrator output to OV.
IO- Remove the lOGa resistor from the testy fiiture and in-
stall the 1OOMQ resistor.
11. Select the 201~4 range, disable ZERO CHECK, allow the
reading to settle and enable SUPPRESS~ in that order.
12. Set the calibrator to output the voltage listed in Table
8-4 for the 2OnA range.
13. Perform one of the following operations to digitally
enter the calibration value:
A. From the front panel, adjust the display to read
19.000nA.
8. Over the bus, send A19E-9X.
14. Enable ZERO CHECK. disable SUPPRESS, and set the
Calibrator to output OV.
~15. Disconnect the resistor/shield firture from the ins&u-
ment and connectthe decade resistance box in its place,
as shown in Figure 8-7.
16. Set the decade box to the resistor value listed for the
2& range in the table.
l7 Select the 2pA range and FILTER 0 (disabled).
18. z;ile ZERO CHECK and enable SUPPRESS in that
'19.~~~Set the calibrator to the voltage value listed for the 2pA
range in the table.
-20.20et the calibration constant to exactly 1.9000&, either
from ihe front panel or over the IEEE-488 bus.
8-10