CONTROL SYSTEM
11.3.2 Communication
with
Indoor
Units
11.3.2.1 Communication
Failures
Definition
Two types of communication failures are diagnosed. The communication failures are
checked separately for each IDU channel.
11.3.2.1.1 ‘Bad Communication’ fault
The system keeps a balance of a good/bad communication packet ratio for each active
communication channel. When the ratio getting high , system enters ‘Bad Communication’
fault.
11.3.2.1.2 ‘No Communication’ fault
If no legal transmission or no message received for 30 seconds, system enters ‘No
Communication’ fault.
When in ‘No Communication’ fault, the system will act as following:
If there is no communication in all channels, the following will be performed:
1.
The unit changes to SB.
2.
The system will scan all the communication.
3.
Each channel that is identified as ‘no communication’ channel will be referred as
STBY unit.
4.
The unit resumes its normal operation with only the operative channels.
11.3.3 Temperature Measurements
11.3.3.1 Thermistor
failures
definition
Thermistor
Thermistor is Disconnected
Thermistor is Shorted
OCT
Temp < -40 °C
Temp > 75 °C
OAT
Temp < -40 °C
Temp > 75 °C
CTT
Temp < -30 °C
Temp > 130 °C
SUCT
Temp < -40 °C
Temp > 75 °C
HST
Temp < -30 °C
Temp > 130 °C
RGT
Temp < -40 °C
Temp > 75 °C
11.3.3.2 System responses for different thermistor failure
Thermistor
Default value
System Reaction
OCT 6°C
OAT Cool
35°C
Heat 7°C
CTT
43°C
Forced compressor to OFF after 20 minutes.
SUCT 6°C
HST 43°C
RGT
43°C
ICT 43°C
11.3.4 Flash
Memory
Programming
In order to upgrade the ODU software the auxiliary port will be used. A special application
should be run on a PC to transmit the new firmware.
Revision
0
11-5