Voltech AT5600, Руководство пользователя

Страница: 264 / 438

C H A P T E R 1 3 – T E S T F I X T U R E S
AT5600 User Manual 98-119 issue 14
Page 264
13.5. Compensation
Compensation of the test fixture is equivalent to short-circuit and open-circuit
correction on a component analyzer. It eliminates errors due to stray parasitic
effects which are usually a combination of parallel capacitance between adjacent
wires, sockets, or pins, and series resistance and inductance along the lengths of
wires.
In addition to the open and short circuit correction, the AT5600 has been
enhanced to provide load correction feature (for certain tests only), similar to high
end LCR Meters, which allow you to perform load correction using a transfer
function that determines the relationship between a standard reference value
(pre-
measured known value) and the standard’s a ctual measurement. Load
correction removes errors that cannot be compensated using open and short
circuit correction.
Not all test programs require compensation, and for some programs containing
only high-power tests, compensation is not possible.
It is best to try compensating when developing test programs with the Editor
software. If compensation of the fixture changes the test results, then it should be
applied whenever the program is run in a production situation.
When a program is first loaded on an AT5600, compensation must be performed,
and the results are then stored for future use.
Compensation offsets are deliberately NOT stored in the program nor in the unit,
as these offsets are characteristic of the total environment (program, fixture and
tester) as so would become confusing and ambiguous for users with several units
and/or several fixtures.
For optimum accuracy, compensation measurements should be made;
•
Whenever the test fixture is changed
•
At the beginning of each day or work period
•
Whenever a new test program is loaded into the AT for execution