Liebert 3000 manual 4.4Load Control Features, 4.5Additional Features, 4.4.1Short Cycle Control

System Performance with Advanced Microprocessor Controls

4.4Load Control Features

4.4.1Short Cycle Control

The control system monitors the compressor and prevents it from turning on within 3 minutes of being turned off. If this (on, off, on) occurs too often, 10 times in one hour, a Short Cycle alarm could occur.

4.4.2Sequential 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.

4.5Additional Features

4.5.1Connecting the Analog Sensors

The sensor inputs are factory set to accept a 4 - 20 mA signal. However, the inputs can be changed by removing the appropriate jumpers on the control circuit board. See Table 14, Figure 5 and Figure 6.

The user supplied analog sensors MUST have their own power supply. To reduce the effects of inter- ference from any noise source, the sensor input wiring should be shielded twisted pair and the shield tied to earth ground at one end.

Analog input terminals for field connections are factory wired to the microprocessor board if specified when ordered. Eight terminals are located in the field wiring compartment of the unit. Wire sensors to the terminals as follows:

Table 14 Analog input terminals

Terminal	Signal
41	Input #1 (+)
42	Input #1 (–)
43	Input #2 (+)
44	Input #2 (–)
45	Input #3 (+)
46	Input #3 (–)
47	Input #4 (+)
48	Input #4 (–)

Consult your Liebert supplier for a field installation kit to add these connections after unit delivery, if required.

Table 15 Additional connections available after unit delivery

	Input #1	Input #2	Input #3	Input #4
4–20 mA	Jumper P50.1 & 2	Jumper P50.5 & 6	Jumper P50.9 &10	Jumper P50.13 &14
	and P50.3 & 4	and P50.7 & 8	and P50.11 & 12	and P50.15 & 16
0–5 VDC	Jumper P50.1 & 2	Jumper P50.5 & 6	Jumper P50.9 & 10	Jumper P50.13 & 14
0–10 VDC	NO Jumper	NO Jumper	NO Jumper	NO Jumper
	on P50.1 & 2	on P50.5 & 6	on P50.9 &10	on P50.13 & 14
	and P50.3 & 4	and P50.7 & 8	and P50.11 & 12	and P50.15 & 16

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