I N S T R U C T I O N S
OJ Air2 EXT
67052B 03/18 - (BCH)
English
LIST OF FIGURES
The following figures are located at the back of the instructions:
Fig. 1: Dimensions
Fig. 2: RJ12 ports for Modbus communication
Fig. 3: Pin connections in Modbus port
Fig. 4: Electrical terminal connections
Fig. 5: Modbus connection cable
INTRODUCTION
OJ Air2 EXT is an extension module for OJ Air2 ventilation systems control-
led by an OJ Air2 Master. The module has been specially designed for
ventilation systems.
OJ Air2 EXT is equipped with thermistor inputs and analogue/digital inputs
and outputs, allowing more complex and energy efficient ventilation systems
to be designed.
RS485 Modbus communication makes the system ideal for energy manage-
ment in buildings.
OJ Air2 EXT can be pre-installed in cooling units or other components which
are subsequently integrated with the ventilation system. Thanks to its RS485
Modbus connection, OJ Air2 EXT can be installed at a minimum of cost.
PRODUCT PROGRAMME
Type
Product
OJ Air2 EXT
Extension module for OJ Air2
OJ Air2 Master
Controller for air handling unit, Modbus, IP20
IO module with two pressure transmitters and ana-
OJ Air2 Fan IO
logue/digital inputs and outputs
OJ Air2 HTERM
Hand terminal for operating OJ Air2 system
OJ Air2 LON
LON module for connection to BMS system
INSTALLATION
OJ Air2 EXT should be mounted on a standard 35 mm DIN rail and installed
in a control panel or similar enclosure which complies with local require-
ments on electrical installations.
The 24 V DC supply voltage is provided via the Modbus connection. The
enclosure rating is IP20.
Input and output signals for external sensors and actuators are connected
to OJ Air2 EXT via screw/socket connectors each of which has screw
terminals for max. 1.5 mm
(CU). A maximum of two OJ Air2 EXT modules
2
can be connected to the OJ Air2 Master.
The OJ Air2 EXT module is equipped with:
• 2 x digital potential-free inputs
• 2 x digital potential-free relay outputs, max. 230 V AC / 5 A
• 2 x analogue inputs (0-10 V DC)
• 2 x temperature sensor inputs (PT1000 thermistor)
• 2 x analogue outputs (0-10 V DC)
• 2 x RJ12 ports for internal system Modbus RS485
Supply voltage
The OJ Air2 EXT module is provided with a 24 V AC power supply via the
Modbus cable.
Modbus connection is illustrated in figures 2 and 3. Modbus cable connec-
tion is illustrated in figure 5.
Connection of OJ Air2 hand terminal
It is not possible to connect an OJ Air2 hand terminal to the OJ Air2 EXT
module.
The hand terminal must always be connected to the OJ Air2 Master using
the port marked
• English
Installation of Modbus cable
• Deutsch
Modbus is connected to OJ Air2 EXT via one of the two RJ12 Modbus
• Français
ports.
OJ Air2 EXT is equipped with two RJ12 ports, allowing Modbus connection
• Svenska
and looping to other Modbus components in the application concerned.
The Modbus ports are connected internally in parallel.
• Norsk
• Dansk
Setting OJ Air2 EXT address
The Modbus address is set using the switch on the front of the OJ Air2
EXT module. The address is specified as a Hex decimal value and can be
set within the address range Hex 71 (switch position 1) to Hex 7F (switch
position F). The address Hex 70 (switch position 0) is reserved for factory
testing.
When the OJ Air2 EXT module is connected to an OJ Air2 Master, only Hex
71 (switch position 1) or Hex 72 (switch position 2) can be chosen as the
address.
SPECIFICATION
Sensor inputs
OJ Air2 EXT is equipped with two sensor inputs for PT1000 sensors
(1000 Ω @ 0°C).
Sensor 1 should be connected to the "Tin 1" input, terminals 11 & 12.
Sensor 2 should be connected to the "Tin 2" input, terminals 21 & 22.
The measuring range for the sensors is -40°C to +100°C with a resolution
of 0.01°C.
Accuracy (excl. sensor tolerance) corresponds to max. +/- 0.5°C.
Electrical connections are illustrated in fig. 4. (Modbus Registers see fig. 6).
Digital inputs
OJ Air2 EXT is equipped with two potential-free digital inputs.
Digital input 1 should be connected to the "Din 1" input, terminals 17 & 18
(earth/GND).
Digital input 2 should be connected to the "Din 2" input, terminals 19 & 20
(earth/GND).
Electrical connections are illustrated in fig. 4. (Modbus Registers see fig. 6).
Digital outputs
OJ Air2 EXT is equipped with two potential-free digital relay outputs.
Digital outputs 1 & 2 may be connected to max. 230 V AC/DC, max. 5 A.
Digital output 1 should be connected to the "Dou 1" output, terminals 13
& 14.
Digital output 2 should be connected to the "Dou 2" output, terminals 15
& 16.
Electrical connections are illustrated in fig. 4. (Modbus Registers see fig. 6).
Analogue inputs
OJ Air2 EXT is equipped with two 0-10 V DC analogue inputs.
Analogue input 1 should be connected to the "Ain 1" input, terminals 9
(earth/GND) & 10 (+).
Analogue input 2 should be connected to the "Ain 2" input, terminals 6
(earth/GND) & 7 (+).
Accuracy < ±4%, resolution 10 mV, Rin 20 kΩ.
Electrical connections are illustrated in fig. 4. (Modbus Registers see fig. 6).
Analogue outputs
OJ Air2 EXT is equipped with two 0-10 V DC analogue outputs.
Analogue output 1 should be connected to the "Aou 1" output, terminals 3
(earth/GND) & 4.
Analogue output 2 should be connected to the "Aou 2" output, terminals 1
(earth/GND) & 2.
Accuracy < ±4%, resolution 10 mV, ripple < 10 mV, Iout 0-10 mA, Rout < 10 Ω.
Electrical connections are illustrated in fig. 4. (Modbus Registers see fig. 6).
© 2018 OJ Electronics A/S
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