18
ENG
Hecu CO
2
+0300085EN rel. 2.2 - 07.05.2019
2.10 Installation
For installation proceed as follows, with reference to the wiring diagrams:
• before performing any operations on the control board, disconnect
the main power supply by turning the main switch in the electrical
panel OFF;
• avoid touching the control board, as electrostatic discharges may
damage the electronic components;
• the index of protection required for the application must be ensured
by the manufacturer of the cabinet or by suitable assembly of the
controller;
• if there are several condensing units connected to the same electrical
panel, use a B or B+ residual current device when the compressors
are controlled by inverter; these protection devices must always be
installed always upstream of any AC/A/F RCDs (see the fi gure below):
Tipo
AC/A/F
Wh
I
Δn
≥300 mA
S
Tipo
AC/A/F
I
Δn
≤100 mA
Tipo
B/B+
I
Δn
≥30 mA
kHz
NO
OK
Fig. 2.o
• connect any digital inputs, Lmax = 10 m;
• connect the temperature and pressure probes, Lmax = 10m;
• connect the electronic expansion valve cable the connectors J17 and
J21;
• connect the inverter serial communication cable to terminal J10 (if
featured);
• connect the PGDe terminal (required for commissioning) to connector
J17;
• connect the power supply to the controller and the inverter, where
featured;
• program the controller using the guided commissioning procedure:
see the chapter on “Commissioning”.
• connect the electrical loads to the relay outputs only after having
programmed the controller. Carefully evaluate the maximum ratings
of the relay outputs as indicated in the Technical specifi cations;
• connect the supervisor serial line to the optional BMS RS485 card.
Important: avoid installing the controllers in environments with
the following characteristics:
• relative humidity greater than 90% or with condensation;
• strong vibrations or knocks;
• exposure to water sprays;
• exposure to aggressive and polluting atmospheres (e.g.: sulphur and
ammonia gases, saline mist, smoke) which may cause corrosion and/
or oxidation;
• strong magnetic and/or radio frequency interference (thus avoid
installation near transmitting antennae);
• exposure to direct sunlight and the elements in general.
Important: the following warnings must be observed when
connecting the controllers:
• incorrect connection to the power supply may seriously damage the
controller;
• use cable ends suitable for the corresponding terminals. Loosen each
screw and insert the cable ends, then tighten the screws and lightly
tug the cables to check correct tightness;
• separate as much as possible the probe and digital input cables from
cables to inductive loads and power cables, so as to avoid possible
electromagnetic disturbance. Never run power cables (including the
electrical panel cables) and probe signal cables in the same conduits;
• do not install the probe cables in the immediate vicinity of power
devices (contactors, circuit breakers, etc.);
• reduce the path of probe cables as much as possible, and avoid spiral
paths that enclose power devices.
Important: Class A software structure: the thermal protection
devices for overload and high pressure must act directly on the
compressor actuator, and must therefore be wired in series with the
compressor contactor coil control.
Note: serial connection starts from terminal J10 on Hecu CO2 and
runs through the power+ inverter and all the MPXPRO controllers
installed on the refrigerated units. The maximum number of MPXPRO
controllers is 5, the limit for this application.
The following recommendations must be observed:
• connect the two twisted wires to the Tx/Rx+ and Tx/Rx- terminals;
• connect the single wire to the GND terminal;
• connect the shield to earth at one end only;
• use a shielded cable (e.g. Belden 3106A - AWG 22);
• For supervisor serial network connection only: connect a 120 Ω
terminating resistor between the Tx/Rx+ and Tx/Rx- terminals on the
last controller in the network (the one furthest away from Hecu).
Earth
Signals (+/-)
GND
AWG 20/22
Device
1
Device
2
Device
n
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