Omega RD-MV100 Series, User Manual

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2-3
Before Using the Recorder
2
2.3 Input Signal Wiring
CAUTION
If a strong tension is applied to the cable wired to the recorder, the terminals of
the recorder and/or the cable can be damaged. In order to prevent tension from
being applied directly on the terminals, fasten all wiring cables to the rear of the
mounting panel.
Precautions to be taken while Wiring
Take the following precautions when wring the input signal cables.
• It is recommended that crimp-on lugs (designed for 4 mm screws) with
insulation sleeves be used on the lead wire ends for the optional screw
terminals (suffix code /H3).
Crimp-on lug
• Take measures to prevent noise from entering the measurement circuit.
• Move the measurement circuit away from the power cable (power circuit) and
ground cable.
• It is desirable that the item being measured does not generate noise. However, if
this is unavoidable, isolate the measurement circuit from the item. Also, ground the
item being measured.
• Shielded wires should be used to minimize noise caused by electrostatic induction.
Connect the shield to the earth ground terminal of the recorder as necessary (make
sure you are not grounding at two points).
• To minimize noise caused by electromagnetic induction, twist the measurement
circuit wires at short, equal intervals.
• Make sure to earth ground the earth ground terminal through minimum resistance
(100
Ω
).
• When using internal reference junction compensation on the thermocouple
input, take measures to stabilize the temperature at the input terminal.
• Always use the input terminal cover.
• Do not use thick wires which may cause large heat dissipation (cross sectional
area 0.5 mm
2
or less recommended).
• Make sure that the air temperature remains reasonably stable. Large temperature
fluctuations can occur if a nearby fan turns ON or OFF.
• Connecting the input wires in parallel with other devices can cause signal
degradation, affecting all connected devices.
If you need to make a parallel connection, then
• Turn the burnout function OFF. (See section 5.9)
• Ground the instruments to the same point.
• Do not turn ON or OFF another instrument during operation. This can have
adverse effects on the other instruments.
• RTDs cannot be wired in parallel.