Hioki Super megohm SM7110 - Page 20

14
Operating Precautions
CAUTION
You must not operate the EXT I/O MODE switch (NPN/PNP) during the instrument
turned on.
Select the external I/O mode between NPN and PNP based on devices that are
externally connected (p. 110).
Before connecting the communication cable to the instrument
DANGER
To avoid electrical hazards and damage to the instrument, do not apply voltage
exceeding the rated maximum to the EXT I/O terminal.
CAUTION
• Use a common ground for both the instrument and the computer. Use of di󰀨erent
ground circuits will result in a potential di󰀨erence between the instrument’s ground
and the computer’s ground. If the communications cable is connected while such a
potential di󰀨erence exists, it may result in equipment malfunction or failure.
• Before connecting any communications cable to the instrument or disconnecting any
communications cable from the instrument, always turn o󰀨 the instrument and the
computer. Failure to do so could result in equipment malfunction or damage.
• After connecting the communications cable, tighten the screws on the connector
securely. Failure to secure the connector could result in equipment malfunction or
damage.
Before performing the open correction
WARNING
If an open correction is carried out, a measurement voltage is instantly output
from the measurement terminal.
Before carrying out an open correction (pressing the F2 key [EXEC]), check that
no human body is in contact with any jigs or measurement circuits. There is the
risk of an electric shock because a maximum voltage of 2000 V is produced.
Before using the instrument as an ammeter
CAUTION
• To avoid malfunctions of the instrument, insert an adequate protective resistor
between the external power supply and the object to be measured. A short-circuit of
the terminals of the object causes the instrument to be subject to a voltage output
from the external power supply.
• To avoid malfunctions of the instrument, limit the input current at up to 1.8 mA during
the testing using a measurement voltage of between 1000 V and 2000 V.
See “Appx. 5 Using Instrument as Ammeter (If Operated in Combination With External Power
Supply)” (p. Appx.7).