Technical data

19
Envoy Installation, Commissioning & Operating Manual
Twin Wire Operation
The panel can be converted to ‘Twin Wire’ operation by selecting Dil switch 5 on each zone card (hy-
spec zone cards only). Any individual zone, or all zones , can be selected as twin wire. The twin wire is
designed to operate with polarised 470R call points, Apollo and Hochiki ‘SAV-WIRE’ bases only. See
page 24 for part No.s. Any standard 24v bell, siren or strobe, that is polarised and suppressed can be
used, providing sounder o/p limits are not exceeded. Short circuit as fire and non latching zones cannot
function on a twin wire zone. When twin wire operation is selected, the conventional zone circuit is
disabled by the software. The sounder CCT terminals should be used for connection of detectors, call
points and sounders.
When used as a twin wire system, use sounder 1 on the main card (PCENV-M-5) and remove the 4K7
resistor in sounder 2, to enable correct monitoring, as these circuits work in tandem.
Where a single zone twin wire system is installed (normally non compliant) and two sounder outputs are
required the following modification can be employed:
Remove both 4K7 EOL resistors from SNDR 1 and 2 and substitute with 10K ohm resistors (or 2 x 4K7
in series). This enables sounders and / or detectors to be used on both legs to provide 2 monitored
circuits on one zone, thus enabling full compliance for twin wire, with only one zone.