Before Starting Measurements
3-5
IM 755601-01E
3
3.4 Wiring
CAUTION
Do not apply any voltage or current across the measurement input
terminals and across the measurement input terminal and the guard
(the outside of the BNC connector). The maximum common-mode
voltage across the case and input terminals is
±
42 Vpeak. Not meeting
these conditions can damage the instrument.
Wiring Method
Connect BNC cables to each terminal as shown in the figure below.
L
CUR
CUR
POT
POT
L
H
H
UNKNOWN
Do not connect a current/voltage
source to the UNKNOWN terminals.
It will damage the instrument.
Resistor under measurement
ALL TERMINALS 42 V PEAK TO
Wiring Precautions
The accuracy specifications can only be met if the following conditions, given in the
wiring example below, are provided.
Wiring Example
H
CUR
r
1
R
x
r
2
I
s
r
2
+
-
r
1
H
POT
L
POT
L
CUR
Pre-amp
Circuit used to
detect disconnection
Circuit used to
detect disconnection
Circuit used to
detect disconnection
Circuit used to
detect disconnection
Constant current source
for measurement
Is:
Test current
Rx:
Resistor under measurement
r1, r2: Resistance of the lead wires (includes contact resistance)
Is
×
r1
≤
1.5 V:
For checking the normal operation of the constant current
source
r2
≤
15
Ω
(for 1
Ω
range):
Because the circuit used to detect disconnection feeds a
r2
≤
30
Ω
(for other ranges) minimal amount of current so that it can detect disconnection
during measurement.
