Appendix 8 Zero Adjustment
A11
Appendix
To perform zero adjustment appropriately
Table 1 shows the correct and wrong connections. The resistances in the figure
indicate lead resistances; there will be no problem if they are less than few Ω
respectively.
In (a), if you connect SENSE-H and SENSE-L as well as SOURCE-H and
SOURCE-L respectively, and use one path to make connection between SENSE
and SOURCE, no potential difference occurs between SENSE-H and SENSE-L,
and 0 V is input. This enables zero adjustment to be carried out correctly.
In (b), on the other hand, if you connect SENSE-H and SOURCE-H as well as
SENSE-L and SOURCE-L respectively, and use one path to make connection
between Hi and Lo,
I × R
Short
voltage occurs between SENSE-H and SENSE-L.
For this reason, the pseudo 0 Ω connection state cannot be achieved and zero
adjustment cannot be carried out correctly.
Table 1: Connection methods
(a) Use one point each between SENSE and
SOURCE for connection
(b) Use one point each between
Hi and Lo for connection
Resistance between
SENSE-H and SENSE-L
R
SEH
+ R
SEL
R
SEH
+ R
Short
+ R
SEL
Measurement current I's
flow path
R
SOH
→ R
SOL
R
SOH
→ R
Short
→ R
SOL
Voltage occurring be-
tween SENSE-H and
SENSE-L
0
I × R
Short
As connection method for
zero adjustment
Correct Wrong
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