30 System Performance with Advanced Microprocessor Controls
4.3 Control Types
4.3.1 Proportional Control
This is a standard control method that maintains the room at a temperature proportional to the load.
The temperature maintained increases as the room load increases. At full load the room would be con-
trolled at a temperature equal to the temperature setpoint plus the temperature sensitivity. If propor-
tional control is selected, the gain is factory set and cannot be adjusted by the user. Operator inputs
are the usual setpoint and sensitivity adjustments.
4.4 Load Control Features
4.4.1 Short Cycle Control
The control system monitors the compressor and prevents it from turning on within a 3 minute period
of being turned off. If this (on, off, on) occurs too often, ten (10) times in a one hour period, a Short
Cycle alarm could occur.
4.4.2 Sequential Load Activation Control
The control allows only one load output to be energized at a time on a restoration of power or micro-
controller reset. Each additional load output will be activated at one second intervals until desired
operating conditions have been met.
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