2 - GENERAL DESCRIPTION
2.1 - General
PRO-DIALOG Plus is a system for controlling units which use
screw compressors:
• Single or dual circuit
• Air or water-cooled condensers
• Non-reversible heat pumps
PRO-DIALOG Plus controls compressor start-up and demand
limits needed to maintain the desired entering or leaving temperature
setpoint for water. It automatically sets the position of
the electronic expansion valve (if used) to optimise the evaporator
charge. It controls operation of the fans (on air-cooled
units) or water valves (on water-cooled units) to maintain the
correct head pressure in each circuit.
Safety circuits are constantly monitored by PRO-DIALOG
Plus to ensure safe operation of the unit. PRO-DIALOG Plus
also gives access to a Quick Test program covering all inputs
and outputs.
All PRO-DIALOG Plus controls can work in accordance with
three independent modes:
• Local mode: the machine is controlled by commands from
the user interface.
• Remote mode: the machine is controlled by remote
contacts (volt-free contacts, analogue signals).
• CCN mode: the machine is controlled by commands from
the Carrier Comfort Network (CCN). In this case a data
communication cable is used to connect the unit to the
CCN communication bus.
The operating mode must be chosen with the Operating Type
selection button described in section 4.2.1.
When the PRO-DIALOG Plus system operates autonomously
(Local or Remote mode) it retains all of its own control capabilities
but does not offer any of the features of the CCN
network.
2.2 - Abbreviations used
In this manual the circuits are called circuit A and circuit B.
The compressors in circuit A are labelled A1 and A2. Those in
circuit B are labelled B1 and B2.
The following abbreviations are frequently used:
AI - Analogue Input
AO - Analogue Output
CCn - Operating type: CCN
CCN - Carrier Comfort Network
DI - Discrete Input
DO - Discrete Output
EXV - Electronic Expansion Device
LED - Light Emitting Diode
Loader - Compressor capacity step
LOFF - Operating type: Local off
rEM - Operating type: by remote control contacts
SCPM - Compressor Protection Module
SCT - Saturated disCharge Temperature
SIO - Standard Input/Output - internal communication
bus linking the basic board to the slave boards
SST - Saturated Suction Temperature