XITRON 2000I, User Manual

Page: 64 / 96

64
2000I & 2000M User Guide, Rev B
Table 3: Current Accuracy Margins
Input
Level
Accuracy
For 90-Day
Specification
Accuracy
For 1-Year
Specification
10mA 210nA 315nA
1mA 15.5nA 26nA
100
µ
A
2.1nA 3.2nA
10
µ
A
275pA 400pA
0 25pA 50pA
Important Note:
The combination of the resistance and DC voltage
measurement uncertainty should not exceed the figures shown in Table 2.
When calculating the uncertainty of the DC voltage measurement, be sure to
include the effects of input impedance (at the 1V DC level) and the input
current of the measuring instrument. Any zero offsets in the measuring
system can be compensated for by calibrating the zero current of the system
using an open circuit measurement.
Initiating External Calibration
To initiate an external calibration you may be required to enter a password
and/or the common (global) password.
Important Note:
The V or I mode (known state) must be set before per-
forming external calibration or password entry is ignored.
1. To obtain optimum accuracy, perform an internal calibration immediately
prior to initiating an external calibration.
2. To initiate the external calibration procedure: press the MNU key on the
front panel and then repeatedly press an arrow key (i.e., 2, 4, 6 or 8) until
the display shows the following message:
< External Cal >