OSTBERG HERU 70 K EC, Assembly And Installation Instructions Manual

Page: 42 / 80

42
SCHEMATIC DIAGRAM FOR HERU
®
K PLACED IN A WARM SPACE
The HERU
®
K should be installed according to picture.
Allowances must be made to access the unit for servicing or maintenance.
PLACING THE HERU
®
K UNIT
The control board of the unit is equipped with a
3-pole RS485 interface and is located on one short
end of the control board. The terminal is marked
with ‘A’, ‘B’ and ‘0’.
Three conductors are used to connect; two of the
binary data signal at the terminals ‘A’ and ‘B’, and
one conductor at the terminal for signal reference
marked ‘0’.
If no conductor is connected on terminal ‘0’ betwe-
en the control system and the unit, there is a risk
for a voltage potential between the unit and the
external control equipment, which can result that
the unit’s control board and/or the external control
equipment is damage.
The data protocol Modbus RTU is used for RS485 .
The external control equipment must support that
data protocol to commucate with the unit.
The hardware of the control board is prepared for
Modbus, but the feature is not enabled by default.
It can be activated with the Modbus compatible
remote control and then synchronized with the unit
which enables activation of the Modbus features.
For more information about configuring the Modbus
via the remote control, see chapter: Menu ”Service
Menu” and Modbus on page 62.
CONNECTING THE MODBUS TO EXTERNAL CONTROL EQUIPMENT
0
HERU
®
Unit
Control unit
Intake grille
Fresh air duct
Silencer
Supply air duct
Extraxt air duct
Exhaust air duct
Roof terminal
Cooker hood
0
✓
1270421_utg2_HERU_K_SV_EN.pdf 42 2018-03-12 10:00:17