Load Control Features; Short Cycle Control; Sequential Load Activation Control; Additional Features - Liebert CHALLENGER 3000 Operation And Maintenance Manual

4.4

Load Control Features

4.4.1

Short 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.
4.4.2

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.
4.5

Additional Features

4.5.1

Connecting 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
41
42
43
44
45
46
47
48
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
4–20 mA Jumper P50.1 & 2
and P50.3 & 4
0–5 VDC Jumper P50.1 & 2
0–10 VDC NO Jumper
on P50.1 & 2
and P50.3 & 4
Signal
Input #1 (+)
Input #1 (–)
Input #2 (+)
Input #2 (–)
Input #3 (+)
Input #3 (–)
Input #4 (+)
Input #4 (–)
Input #1 Input #2
Jumper P50.5 & 6
and P50.7 & 8
Jumper P50.5 & 6
NO Jumper
on P50.5 & 6
and P50.7 & 8
System Performance with Advanced Microprocessor Controls
Input #3
Jumper P50.9 &10
and P50.11 & 12
Jumper P50.9 & 10
NO Jumper
on P50.9 &10
and P50.11 & 12
34
Input #4
Jumper P50.13 &14
and P50.15 & 16
Jumper P50.13 & 14
NO Jumper
on P50.13 & 14
and P50.15 & 16