2
INM 725B Rev 21
Glossary of Terms
1 .3
Glossary of terms
Cell:
A single module 60mm x 60mm which can be joined to adjacent
cells in varying heights and widths to provide the number of
alarms required. The number of alarms available per Cell
depends on the window size required.
N/C:
A Normally Closed contact which opens in the abnormal state.
N/O:
A Normally Open contact which closes in the abnormal state.
EN:
Energised Relay Coil that De-Energises in the abnormal state.
DE-EN:
De-Energised Relay Coil that Energises in the abnormal state.
Form A:
Normally Open Single Pole, Single Throw Relay (SPST) contact
that closes in the abnormal state.
Form B:
Normally Closed Single Pole, Single Throw Relay (SPST) contact
that Opens in the abnormal state.
Form C:
Changeover contacts, Single Pole, Double Throw (SPDT) contact
both poles change in the abnormal state.
FCV:
Field Contact Voltage. (Wetting Voltage)
Card:
Refers to individual electronic circuit boards. There are various
types of Cards used within the RTK 725B i.e. Alarm Cards, Relay
Cards, Supply Cards and Communication Cards.
