Control System - Airwell Delta 25 Service Manual

11.

CONTROL SYSTEM

11.1 General Functions and Operating Rules
The DCI software is fully parametric.All the model dependent parameters are shown in Blue color
and with Italic style [parameter].
The parameters values are given in the last section of this control logic chapter of the service
manual.
11.1.1
System Operation Concept
The control function is divided between indoor and outdoor unit controllers. Indoor unit is the system
'Master', requesting the outdoor unit for cooling/heating capacity supply. The outdoor unit is the
system 'Slave' and it must supply the required capacity unless it enters into a protection mode
avoiding it from supplying the requested capacity.
The capacity request is transferred via indoor to outdoor communication, and is represented by a
parameter called 'NLOAD'. NLOAD is an integer number with values between 0 and 127, and it
represents the heat or cool load felt by the indoor unit.
11.1.2 Compressor Frequency Control (NLOAD setting)
The NLOAD setting is done by the indoor unit controller, based on a PI control scheme.
The actual NLOAD to be sent to the outdoor unit controller, is based on the preliminary LOAD
calculation, the indoor fan speed, and the power shedding function.
NLOAD limits as a function of indoor fan speed:
Indoor Fan Speed Maximum NLOAD Cooling
Low
Medium
High
Turbo
Auto
11.1.3 Target Frequency Setting
The compressor target frequency is a function of the NLOAD number sent from the indoor
controller and the outdoor air temperature.
Basic Target Frequency Setting:
NLOAD
127
10 < NLOAD < 127
10
0
SM DEL60Hz 1-E.0 GB
Max NLOADIF1C
Max NLOADIF2C
Max NLOADIF3C
Max NLOADIF4C
Max NLOADIF5C
Target Frequency
Maximum frequency
Interpolated value between minimum and maximum frequency
Minimum frequency
Compressor is stopped
CONTENTS
CONTROL SYSTEM
Maximum NLOAD Heating
127
127
127
127
127
11-1