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3 - HARDWARE DESCRIPTION
3.1 - General description
Each circuit is by default fitted with one SIOB board used
to manage all major inputs and outputs of the controller.
The control system includes variators for compressor and
fan control, as well as AUX1 boards used to manage
additional inputs and outputs. Options such as hydraulic
kit or master/slave assembly control require an additional
AUX1 board. Energy management module requires the
installation of NRCP2 board.
All boards communicate via an internal LEN bus.
3.3 - Power supply to boards
All boards are supplied from a common 24 VAC supply
referred to earth.
CAUTION: Maintain correct polarity when
connecting the power supply to the boards,
otherwise the boards may be damaged.
In the event of a power supply interrupt, the unit restarts
automatically without the need for an external command.
However, any faults active when the supply is interrupted
are saved and may in certain cases prevent a given circuit
or the unit from restarting.
3.4 - Light emitting diodes on boards
All boards continuously check and indicate the proper
operation of their electronic circuits. A light emitting diode
(LED) lights on each board when it is operating properly.
•
The red LED flashing for a two-second period on the
SIOB board indicates correct operation. A different
rate indicates a board or a software failure.
•
The green LED flashes continuously on all boards to
show that the board is communicating correctly over
its internal bus. If the green LED is not flashing, this
indicates a LEN bus wiring problem.
The main board continuously monitors the information
received from various pressure and temperature probes
and accordingly starts the program that controls the unit.
The unit is equipped with the Touch Pilot user interface
(7-inch touch screen).
3.2 - Electrical box
The electrical box includes all boards controlling the unit
and the Touch Pilot user interface.
NOTE: The pictures are for reference only.
3.5 - Pressure sensors
Two types of electronic sensors (high and low pressure)
are used to measure various pressures in each circuit.
These electronic sensors deliver 0 to 5 VDC. The sensors
are connected to the SIOB board. Liquid pressure sensors
are connected to the AUX1 board and water pressure
sensors of the optional hydraulic kit are connected to the
additional AUX1 board.
Discharge pressure sensors (high pressure type)
These sensors measure the discharge pressure in each
circuit. They are used to control head pressure. Discharge
pressure sensors are mounted on the discharge line piping
of each circuit.
Suction pressure sensors (low pressure type)
These sensors measure the suction pressure in each circuit.
They are used for EXV control. Suction pressure sensors
are located on the suction piping of each circuit.
Oil pressure sensors (high pressure type)
These sensors measure the oil pressure of each compressor.
Oil pressure sensors are located at the oil port of the
compressor. The suction pressure is subtracted from this
value to arrive at the differential oil pressure.
Economizer pressure sensors (high pressure type)
These sensors measure the pressure on the economizer
line. They are used to control the economizer performance.