Emerson Liebert iCOM Manual De Usuario

The Liebert iCOM Optimized Aisle control monitors the inlet temperature to the racks using up to 20 

rack temperature sensors that are connected to a Liebert iCOM control. These inlet rack temperature 

sensors are used to control the air flow (fan speed) of each unit. The air flow is increased when the 

inlet rack sensors detect a temperature higher than the setpoint and will decrease air flow when the 

head load decreases or changes to the application are modified (eg., Containment).

Refer to Application and Configuration of Rack Sensors on page 81 for rack sensor setup 

details.

• The cooling unit’s fan speed is determined based on the amount of deviation from temperature 

setpoint (Proportional) and the length of time the actual temperature has deviated from 

temperature setpoint (Integral)

• The fan speed control takes into account the actual temperature as it compares to the 

temperature setpoint and will modify how fast the fans can change speed to avoid overshooting 

the setpoint.
In addition to the speed filters, the fan speed also has programmed independent acceleration and 

deceleration rates
These control tuning parameters allow the fans to speed up quickly to match rapid heat load 

changes and react to containment doors being opened and closed while still providing stable 

control when the application returns to steady state operation.

Temperature compensation links between the cold aisle temperatures, cooling capacity and air flow. 

Changes that could invoke temperature compensation would be the removal of floor tiles in non-cold 

aisle areas, incorrect supply temperature setpoint, unit failure in another zone or heat load changes 

greater than expected heat load changes in rack equipment. As a further protection, the temperature 

compensation routine also ties into the cascade /standby operation when Teamwork Mode 3 is 

selected.
There are three selectable compensation routines to choose from: Return, Supply or Return + Supply. 
Return Compensation: This temperature compensation monitors the return air condition and 

automatically adjusts the supply air setpoint if return temperatures become too cold. Return 

compensation can be enabled in all fan and temperature control sensor configurations, with the 

exception of fan and cooling set for return air control (Enable Return Compensation falls back to No). 

With return air compensation enabled, S103 “Temperature Setpoint” remains unchanged as long as 

the air temperature is above S114 “Return Compensation Setpoint.” 
If the return air temperature falls below S114 “Return Compensation Setpoint,” S103 “Temperature 

Setpoint” will be increased. The calculated compensation setpoint is displayed as the left hand value 

(Act) of line S103 (see Figure 49). Return compensation is also indicated from the unit view as shown 

in Figure 50.