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Connecting Humidity Sensor
2.4 Connecting Humidity Sensor
Be sure to read “Before connecting the Humidity Sensor to the instrument” (p. 11) beforehand.
The Humidity Sensor is optional. (p. 4)
Required sensor: Model Z2011 Humidity Sensor
Install the Humidity Sensor close to the object to be measured. This enables the environment,
temperature and humidity, around the object also to be measured simultaneously.
TEMP. SENSOR
terminal
2.5 Grounding Instrument
Be sure to read “Before grounding the instrument” (p. 12) beforehand.
Choose between connecting the OUTPUT terminal with the GROUND terminal (ground) and
connecting the GUARD terminal with the GUARD terminal using the shorting plug.
(1) If measuring insulation resistance or ground insulation resistance of the measured object * with
one line grounded (Grounding the OUTPUT terminal)
Grounding the OUTPUT terminal allows the negative setting voltage to be applied to the GROUND
terminal.
To measure an object whose one line is grounded, connect the shorting plug as shown in the gure below.
Connect the grounded line of the object with the GROUND terminal (OUTPUT), and the non-
grounded line with the INPUT terminal.
If you connect the grounded line of the object with the INPUT terminal, and the non-grounded line
with the GROUND terminal, a current will leak to the ground, causing an error of the measured value.
INPUT
GUARD
GROUND
CHARGE
OUTPUT
A
SM7110/SM7120
Shorting plug
Measurement
voltage
source
−
+
Current limiter
Ammeter
IMPORTANT
Be sure to connect the GROUND terminal to the OUTPUT terminal.
Even when the GROUND terminal is not connected to the OUTPUT terminal, the positive (+)
voltage can be applied on the ground side terminal of the measured object if the GROUND
terminal is connected to the ground terminal of the object. In that case however, noise can be
easily superimposed on the input circuit, resulting in unstable measurement.
* Arrester, transformer, power transmission line, distribution line, etc.
2
Preparing for Measurement
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