American Power Conversion DX Manual De Usuario

Similar to DX cooling, the output for dehumidification is determined by the 

difference between the setpoint and the average return humidity from each of the Modules in the 
System (if more than one Module is present). The deadband is used to engage both compressors 
incrementally with increasing demand. Each Module in the System is assigned an equal division of 
the deadband (a percentage of relative humidity). Both compressors in a Module are engaged when 
the assigned division of the deadband (above the setpoint) is reached. If the average return humidity 
reaches the setpoint plus the entire deadband, all of the compressors will be engaged until the 
humidity drops below the setpoint plus the deadband. Unlike DX cooling, the compressors in each 
Module are normally set to work as a single unit instead of separately. The use of one or two 
compressors per Module is based on the Dehum. Capacity setting (Path: Main Menu > Setup > 
System # > System Config > System Options).

See “Deadbands” on page 34 for instructions on setting the DX dehumidify deadband.

MultiCool dehumidify mode is controlled by the dehumidify PID 

controller. When the return humidity rises above the setpoint, the dehumidify output increases as the 
return humidity rises until the output reaches 100%

See “How to tune the PIDs” on page 38 for a description of the PID controls and see 
"“How to tune the PIDs” on page 38 for instructions on tuning the dehumidify PID loop.

The steam cylinder humidifier output is controlled by the humidify proportional 

controller. When the return humidity drops below the humidify setpoint, the humidifier output will 
increase as the return humidity drops until the output reaches 100%.

See “Humidification sensitivity” on page 39 for a description of the Humidification 
sensitivity band.