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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
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
11.1.2.1 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
Max NLOADIF1C
Medium
Max NLOADIF2C
High
Max NLOADIF3C
Turbo
Max NLOADIF4C
Auto
Max NLOADIF5C
NLOAD limits as a function of power shedding:
Mode
Power Shedding OFF
Cool
No limit
Heat
No limit
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
Service Manual – WNG DCI
Target Frequency
Maximum frequency
Interpolated value between minimum and maximum frequency
Minimum frequency
Compressor is stopped
nless it enters into a protection mode
Maximum NLOAD Heating
127
127
127
127
127
Power Shedding ON
Nominal Cooling
Nominal Heating
Revision 0
CONTENT
CONTROL SYSTEM
11-1
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