11-10
CONTROL SYSTEM
SM YAZDCI 1-A.1 GB
11.5 Run
Mode
Run mode is the default operation mode of the system. This is the standard operation mode that
is active in field application (at customer site).
System can go from run mode to other operation modes through keyboard or serial ports.
11.5.1 Mode
Setting
Mode defines the ODU operation mode. There are three possible operation modes:
1.
STBY – standby mode
2.
COOL - the unit operating at cooling cycle
3.
HEAT - the unit operating at heat pump cycle
The ODU define the system operation mode according to three methods set by the display key
board:
1.
First request priority
The first IDU which requests different mode than STBY mode will set the new
operation mode. The mode will change once all the units exit the current operation
mode.
2. Priority
unit
If an IDU is defined as a priority unit, the operational mode will be defined according
to that unit request, unless the unit is at STBY mode.
In case priority unit is SB the mode will be set acceding to first request priority.
3.
Forced operation mode
If forced mode is enabled than the ODU mode will be forced according to the
Forced mode input:
Open COOL
Short HEAT
The ODU will go to SB if all the IDU are at SB or at different modes.
4. SB
Input
The ODU will change mode between COOL/HEAT and Idle according to the STBY
dry contact input as follows:
STBY input
ODU mode
Short
SB
Short Open
last mode
Open
according normal mode selection
11.5.2
Compressor Speed Control
11.5.2.1
Compressor Min On/Off time
Compressor minimum OFF time is MinOFFTime minutes except during Deicing protection.
Compressor minimum ON time is MinOnTime minutes, minimum ON time is ignored during
protections, and when unit is turned to STBY.
