19/44 NT00000792-KUBAIR-F400-ECOWATT-VENTDRIVE-AN-220314
5.2 Modbus connection - Connection to a BMS
In the case of a connection to a BMS, the Modbus connection allows, according to unit versions:
• KUBAIR F400 ECOWATT
®
– VAV variable airflow driving:
-
On / Off,
-
Speed adjustment,
-
Reading of registers.
• KUBAIR F400 ECOWATT
®
– Adjustment to CAV constant airflow or COP constant pressure:
-
On / Off,
-
Reading of registers.
Recommendation for ModBus connection.
The controller is equipped with four Modbus connectors :
• 3 RJ12 connectors,
• 3 spring terminals, Bus A, Bus B and GND.
A
B
Gnd
1
2
3
C
V+
Add. Pin 1
Bus B
Bus A
V+
Gnd
A
V+
Add. Pin 1
Bus B
Bus A
Add. Pin 2
Gnd
B
Add. Pin 1
Bus B
Bus A
Add. Pin 2
Gnd
The 3 RJ12 connectors are marked "A", "B" and "C".
• "A": Modbus connection, slave, +24V voltage in the connector.
• "B": Modbus connection, slave, no +24V voltage in the connector. For connection to a PC software
with a USB-RS485 adapter - RJ12 connection.
• "C": Modbus connection, master, external equipment (ETDZ A connection, accessory not supplied).
We recommend using an unshielded 6-core telecommunication cable, 30 AWG/0.066 mm² flat with RJ12
connectors at each end, keeping the same wire colour sequence.
Each controller has a pre-installed Modbus termination resistor of value 1 kΩ which is sufficient for most
applications.
An additional Modbus terminating resistor should not be used except for the following installations where
the Modbus exceeds 100 m for an in-line Modbus connection (Daisy Chain - typical industrial architec-
ture). If the Modbus exceeds 100 m, it may be necessary to install an additional termination resistor
worth 180 Ω. The resistor must be installed on the last line controller. For Modbus star installations, a
Modbus terminating resistor is not required.
