4 How to Use
4-3. Precautions for system designing
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Proper use of alarm contact
The alarm contact of the detector is used to transmit signals to activate an external buzzer, an alarm lamp or
a rotating lamp. Do not use the detector for controlling purpose (e.g., controlling the shutdown valve.)
The specifications for the alarm contact of the detector are based on the resistant load conditions. If
inductive load is used at the alarm contact, the following errors will occur easily because counter
electromotive force is generated at the contact.
Deposition, defective insulation or defective contact at the relay contact
Damage of any electric parts due to high-voltage generated inside the detector
Abnormal operations by an out-of-control CPU
If load is to be activated, appropriate measures must be taken to stabilize the operation of the detector and
protect the alarm contact referring to the following information.
Relay it with an external relay at a lower voltage of 100 VAC or below (contact amplification). At the same
time, the surge absorbing part SK1 suitable for the specifications must be attached to the external relay.
In addition, the surge absorbing part SK2 must be attached to the loaded side of the external relay if
necessary.
It may be recommended that the surge absorbing part should be attached to the contact for certain load
conditions. It must be attached to an appropriate position by checking how the load is activated.
CAUTION
In principal, do not activate inductive load at the alarm contact of the detector. (In particular, never use the
inductive load to activate a fluorescent lamp or motor.)
If inductive load is activated, relay it with an external relay (contact amplification). However, because the
coil of an external relay also involves inductive load, select a relay at a lower voltage (100 VAC or below),
and then protect the contact of the detector with an appropriate surge absorbing part, such as a CR circuit.
