Rev. d 01/1 15
DMP052E
It is important that all equipment connected to LinkBus, which must transmit their data, have the
same NDL value. For example, if only three equipment on four must transmit data, three shall have
n d L
= 3 and one
n d L
= 1. The equipment which must not transmit data, but only receive,
must have
idl
address higher than the equipment which transmits.
For example: if only three equipments on four must transmit data, three shall have
i d L
= 1, 2, 3
and one
i d L
= 4. A low ndl value increases data update which occurs in a minimum time of 40
sec. with 10 sec. for each transmitting controller. The advisable max distance between to extreme
equipment of LinkBus is 10 m. Such distance should allow any connection inside an electrical
switchboard. It is strongly recommended the use of shielded cables with earth screen at one end
only, if power equipment (contactors, inverters, UPS, reactors, etc.) is present. It is essential to
keep adequate distance (30 cm. at least), between cable and wires, otherwise use metal tracks. It
is recommended the use of 24 AWG or 26 AWG twisted pair and do not carry out star connections.
The default values of the Bus menu are
i d L
= 1 and
n d L
= 1. For LinkBus address setting
and sensor selection see page 20.
ENTHALPY COMPARISON WITH OUTDOOR HUMIDITY SENSOR FROM ANOTHER
W500H
When the function Enthalpy Comparison is active (mode A3 for analogue output 2 and/or D3 for
relay output 2) it is possible to utilize
SH
signal from another W500H as outdoor humidity sensor.
In this case we achieve a complete Enthalpy comparison of temperature and humidity using the
outdoor humidity value sent through the LinkBus by another W500H. Practically, each W500H
copies its SH signal value on the
SSE
channel (outdoor sensor signal) to share it with other
W500H. E.g. if a controller with address
i d L
= 1 requires to use as outdoor humidity sensor the
one connected to another controller with address
i d L
= 2, it must set the reading value of the
external channel as
S S E
= 2
To perform the complete enthalpy comparison it is necessary the presence of both humidity
sensors (indoor and outdoor) with an SSE value different from SSH. When the enthalpy is
complete, it enables all Set Point and the Bands are processed by the following formula
:
Enthalpy= H x 10
(0,0275xT-1)
+T
Attention: parameter USE = ON disables outdoor humidity processing (see page 17).
