Applications 57
Engineering Laboratory Environment Applications
The 2000 instruments have many uses in the Calibration and Engineering Labora-
tory environments.
Short-Term Transfer Standards
The 2000 instruments can be used for medium accuracy transfers in the calibra-
tion laboratory based on their:
DC voltage 24-hour stability (at the 10V level) of 2
.
1ppm, and
DC current 24 hour stability (at the 1mA level) of 6
.
0ppm,
The excellent low level stability of these instruments also enables them to be used
as a bucking type of source for inter-cell comparisons with 0.2
μ
V uncertainty
below 22mV. Refer to Table 1.
The short-term stability for current output enables the use of the 2000 instruments
for resistance transfers. In this application the 2000I or 2000M instrument is set
to a suitable current for the resistance to transfer—a 10V drop across the resistor.
A high accuracy digital voltmeter is used to measure the voltage drop across the
standard. On the same the standard resistor is then replaced by a resistor of un-
known value (one within a 10:1 ratio of the standard).
The value of the unknown resistance is then given by the formula:
R
unknown
= R
standard
* (V
unknown
/ V
standard
)
Note that this method yields better performance, at higher values, than the nor-
mally used practice of placing the two resistors in series and measuring the vol-
tage across each resistor. This is because the voltmeter usually has leakage
current flow to ground in one terminal (usually the LO terminal), which unbal-
ances the circuit for the two measurements. In this method, the circuit is in the
same conditions for each measurement, thus this effect is eliminated. The major
item affecting accuracy is the finite output impedance of the current source,
which is only of importance when the two resistor values are significantly differ-
ent.
Summary of Contents for Xitron 2000 Series
Page 1: ...USER GUIDE 2000 Family DC Temperature Source Instruments...
Page 2: ......
Page 18: ...2000I 2000M Instrument s User Guide Revision B 18...
Page 42: ...2000I 2000M Instrument s User Guide Revision B 42...
Page 47: ...Using the Memory Options 47...
Page 60: ...2000I 2000M Instrument s User Guide Revision B 60...
Page 91: ......
Page 92: ...2000I 2000M Instrument s User Guide Revision B 92...
Page 95: ...Appendix B General Specifications 95...
Page 97: ...Password Page 97...
