Service manual

12-2
CONTROL SYSTEM
SM SX DCI 1-A.3 GB
Target frequency limits as a function of outdoor air temperature (OAT):
OAT Range Cooling Mode limits Heating Mode limits
OAT < 6
MaxFreqAsOATC
No limit
6 ≤ OAT < 15 MaxFreqAsOAT1H
15 ≤ OAT < 28
MaxFreqAsOAT2H
28≤ OAT No limit
12.1.3.2 Target Frequency Setting for DCI 72/80
The compressor Target Speed is calculated according to the following formula:







127
,maxarg
ODUNload
MaxSpeedMinSpeedSpeedetT
load
MiniSpeed, MaxSpeed are defined as following:
When the unit is in the cool mode, MiniSpeedC = 15Hz, MaxSpeed = 75Hz
When the unit is in the heat mode, MiniSpeedH = 20Hz, MaxSpeed = 95Hz
ODU NLOAD is caculated according to the IDU NLoad:






 127,
*3
min
ODUCode
IDUNLOAD
NLOADODU
OAT ODUCodeC ODUCodeC IDUNLOAD
≤-5 3 3
Refer to sect.112.1.2.1
≤-5 3.8 3
12.1.4 Frequency Changes Control
When the unit is running normally , the compressor frequency change rate is 1 Hz/sec.
12.1.5 Compressor Starting Control
12.1.5.1 Compressor starting control for DCI50/60/72Zzz
Time
Step1
Step2
Step3
Min 10 Minutes
1
Minute
1
Minute
CONTENT