CSE Kingfisher PLUS+, Hardware Reference Manual

Page: 19 / 89

Superseded Hardware Manual 7.12 Page 19
1.3 P S U-2: DC S u p p ly In p u t, 18 to 36 VDC
The PSU-2 DC supply (18 to 36 VDC) module provides DC to DC conversion, galvanic isolation,
+12 VDC, +5 VDC and various monitoring functions to power the RTU modules.
An isolated 24 VDC output rated at 10 W (400 mA) is available for powering a limited number of
analog loops or digit input circuits. It cannot be used with inductive loads such as coils, contactors etc.
Power for these is to be provided from a separate supply.
The PSU-2 features optional supply, voltage, current and temperature monitoring circuits that enable
the processor unit to access these as analog and digital points in the system. When the DC supply
fails and the system is powered from external lead acid batteries if connected the voltage monitoring
circuit provides battery cut-off (for battery preservation) when battery cell voltage reaches 10.5 VDC.
The load capacities for each output of the power supply are shown in the following table. Note: the
specifications shown are for the 12 V model of the PSU-2. The PSU-2 was also available as a 24 V
model.
P S U-2 S p e c ific a tio n s
Input Supply 18 to 36 VDC Nominally 24 VDC
Outputs +5 VDC @ <10 W to Bus
+12 VDC @ <50 W to Bus
+12 VDC @ <50 W to Battery
+24 VDC Isolated @ 10 W to Field
Total 50 W max.
Isolation 2.5 kV DC input/DC output
2.5 kV Isolated 24 VDC output
Deep Discharge Protection RTU Shutdown at 10.5 V
RTU Startup at 11.8 V
Supply Fuse 4 A slow blow internal
Monitoring Circuits Battery Current and Voltage, Temperature, DC
Supply
Status Indicators Supplies and Battery on Front Bezel
Connector Removable for DC connectors