4. Installation
4-1 Installation precautions
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• Alarm relay contact welding, insulation failure, contact failure
• Damage to electrical components due to high voltage inside the product
• Malfunctions due to CPU runaway
If the product is used to operate loads, take the following measures to stabilize product operations and protect the
alarm contacts:
• Use an external relay (low voltage, not exceeding 100 V AC) to link the circuits (contact amplification). Add a
surge absorber (SK1) appropriate for the rating to the external relay.
• Where necessary, add a surge absorber (SK2) on the load side of the external relay.
• Depending on the load conditions, it may be better to add the surge absorber to the contact side. Check load
behavior to determine the optimal location.
<SD-3>
* SK1, SK2: Surge absorbers
DANGER
Never use for controls on which human life depends or other mission critical controls (e.g., shutoff valve
controls).
WARNING
Contacts may not function correctly if left inactive for extended periods. Check contact opening and
closing periodically.
Contact faults may occur if exposed to organic gases or sulfidizing gases for extended periods.
In principle, do not use the alarm contacts of the product to operate inductive loads. In particular, never
use to operate devices like fluorescent lamps and motors.
If operating inductive loads is absolutely unavoidable, link the circuits using an external relay (contact
amplification). Since the external relay coil constitutes another inductive load, use a relay operating at low
voltage (under 100 V AC), and protect the product contacts with a suitable surge absorber (e.g., CR
circuit).
Do not use in atmospheres where silicone is present.
Alarm
contact
External relay
(low voltage relay)
Power
supply
Power
supply
Coil
Lo
ad
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