Isolating Base
The Isolating Base senses and isolates short circuit faults on loops. The base is loop - powered, polarity sensitive and accepts the XPERT card to set the associated device address. In short-circuit conditions the integral yellow LED is illuminated.The detector associated with the base remains active under short-circuit conditions. Power and signals to the affected section are restored automatically when the fault is cleared.
The Isolating Base is intended for use with equipment using the SHIELD communication protocol. Under normal operating conditions, a low impedance is present between the - IN and - OUT terminals of the base, so that power and signal pass to the next base in line.
If a short-circuit or abnormally low impedance occurs, the fall in voltage is sensed and the base isolates the negative supply in the direction of the fault. The isolated section is tested using a current pulse every five seconds. When the short-circuit is removed, the power will automatically be restored.
