19
MAN3037-2
XP95 PRODUCT GUIDE
11
XP95 Isolators
The isolating base senses and isolates short circuit faults on XP95
and Discovery loops and spurs. 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
Apollo XP95 and Discovery communication protocol.
11.1 Electrical Description
Under normal operating conditions, a low impedance is present between the –IN and the –OUT terminals of
the base, so that power and signals 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.
If it is a requirement that no device is lost in the event of a single short circuit, every detector should be fitted
to an isolating base.
In applications where it is not necessary to use an isolating base for each detector, up to twenty (20) or
equivalent surge current may be installed between isolating bases.
Stand-alone isolators, which have their own bases, may be used instead of isolating bases. The isolators are
wired to a loop between detectors or other devices.
For further information on the use of isolators in XP95 systems refer to Ampac Product Data sheet PDS201-
9001.
11.2 Product Codes
Product Description
Product Number
Item Number
XP95/Discovery Isolating Base with Xpert Card
45681-284AMP
201-0125
XP95/Discovery Isolator
55000-720AMP
201-0172
XP95/Discovery Isolator Base (for above)
45681-211AMP
201-0006
