SENSORS/CONTROLLERS CONNECTED IN STAR
SENSORS/CONTROLLERS CONNECTED IN BUS MODE
(DAISY CHAIN)
p. 18
Room sensors - Bus Connection
Only OJ Room sensors type WLxx that are prepared for 2 wire communication can be used. Standard
installation cable, maximum 2 x 0.25 mm
2
can be used. The Room sensors can be connected in the
conventional star wiring format, or in a bus connected mode (Daisy chain) see fig 10 + fig 11. The
master has 4 sets of terminals marked Room sensor BUS that can be used for connecting the 2-wire
signal from the Room sensors.
There are 4 identical sets of terminals for convenient installation. Any Room sensor can be connected
to any pair of terminals. The total length of the 2-wire system can be up to 300 m with a maximum
length of 100mbetween any 2 Room sensors.
Remember to c to + and – to – .
Fig 7
From factory the master is delivered with a jumper in the switch/ timer terminals I & O. The day
temperature setpoint is defaulted to 20°C and the night temperature to 15°C. These default settings can
be changed if the master has a display. The current operating set point of the master can be changed
from the day temperature into night temperature, and vice versa by using an input from an external
switch or timer. The input must be a volt free switch, and will need to open circuit for night temperature
and close circuit for day temperature. When the external switch or timer is used to switch to night
setback, this will override any time settings in a WLCT Room controller, including any Room sensors that
are part of a group allocated to that Room controller.
External Switch (TIMER) for night setback
Fig 9
Fig 10
Fig 11
