Liebert 3000 manual Select Control Type, Setup Alarms, Table, Alarm default time delays

Operation with Advanced Microprocessor Controls

Select Control Type

•Intelligent (Chilled Water only)

•Proportional (all unit types)

•Tunable PID (Chilled Water or SCR Reheats only)

The type of system control method used by the microprocessor can be selected from the front panel. The default setting is Intelligent, which approximates the actions that a human operator would take to maintain precise, stable control. The control logic uses Artificial Intelligence techniques including “fuzzy logic” and “expert systems” methods to maintain precise, stable control and increase reliability by reducing component cycles. Proportional is a standard control method that uses one gain factor (temperature sensitivity adjustment). Tunable PID (Proportional, Integral, and Derivative) uses three gain factors selected by the operator. PID allows precision tuning, but requires an experienced operator and seasonal adjustments. Note that if PID is selected, it is used for temperature control while humidity will continue to use Proportional control. Refer to 4.0 - System Performance with Advanced Microprocessor Controls for more detail on types of controls.

Setup Alarms

Selecting SETUP ALARMS will step to the following menu:

•SET TIME DELAYS

•ENABLE ALARMS

•ENABLE COMMON ALARM

•SET CUSTOM ALARMS

Each individual alarm can be programmed with a time delay from 0 to 255 seconds. Each individual alarm can be ENABLED or DISABLED and each individual alarm can be programmed to energize or not to energize the Common Alarm Relay.

Set Time Delays—By programming a time delay for an alarm, the system will delay the specified amount of time before recognizing the alarm. The alarm condition must be present for the amount of time programmed for that alarm before it will be annunciated. If the alarm condition goes away before the time delay has timed out, the alarm will not be recognized and the time delay timer will be reset. For software alarms such as Loss of Power, Short Cycle, and Low Suction Pressure, a time delay will only delay the annunciation of that alarm. The condition of the alarm is not applicable because the condition has already occurred. For these alarms the time delay should be left at the fac- tory default of 0. Table 5, below, shows the default time delays for each alarm.

Table 5	Alarm default time delays
		Default Time
	Alarm	Delay (seconds)
Humidifier Problem		2
High Head Pressure		2
Change Filter		2
Loss of Air flow		3
Custom Alarm #1		0
Custom Alarm #2		0
Custom Alarm #3		0
Custom Alarm #4		6
High Temperature		30
Low Temperature		30
High Humidity		30
Low Humidity		30
Low Suction Pressure		0
Short Cycle		0
Compressor Overload		2
Main Fan Overload		5
Loss of Power		0

9