SFRA45 User Manual
6-3
6.3
Zero Compensation
There are 2 levels of zero compensation:
Trim out the dc offset in the input amplifier chain.
Measure any remaining offset and compensate.
The trim of the dc offset in the input amplifier chain can be
manually performed with the ZERO key, or over the RS232
with the REZERO command. This dc offset trim measures
the dc present while the autozero switch is active and
applies an equal and opposite offset via the D/A converter
so that the input range to the A/D is optimised.
The measurement of the remaining offset also happens
when the offset is trimmed but is also repeated at regular
intervals. This is to compensate for any thermal drift in the
amplifier chain.
Real-time measurement is not possible while the autozero
measurement is in progress so this repeated autozero
function can be disabled via the SYSTEM OPTIONS menu.
(LCR) mode
provides zero compensation information and
is used to remove the capacitive element of test leads
from the measured impedance. Select
“compensate”
then
Enter,
to start zero compensation or,
“clear compensation”
then Enter to clear any previous compensation. The
display shown below appears when the zero key is
pressed. “DUT” means ‘Device under Test’, be sure to clear
compensation before doing further testing.
