User's Manual
KAIROS User Manual - version 1.3
Radio Activity S.r.l. 12/11/2014 21 / 41
PPS to rear plug
Insulated
Insulated
KAIROS “D”:
Slave
Master
1
st
choice
Internal PPS (GPS/GLONASS)
Internal PPS (GPS/GLONASS)
2
nd
choice
External PPS (full)
External PPS (full)
3
rd
choice
Internal ref (full)
Internal ref (full)
4
th
choice
Internal ref (full)
Internal ref (full)
PPS to rear plug
Internal ref
Internal ref
3.3.4 Power supply
The equipment requires a 13.2Vdc nominal power supply with negative to ground. KAIROS switches off
when a polarity inversion or an out of range Vdc values are detected to its power supply input.
An internal circuit protects the equipment during fast voltage transients (e.g.: in mobile application) and
during accidental short circuit. It allows also a “soft start” limiting the in-rush current during the power-on
phase.
KAIROS implements also a non-restoring protection (internal fuse) to save the equipment from heavy
transients due to lightening. This protection acts absorbing the excess energy incoming from the power
supply cable. Note that, after a lightening event, this protection may short the power supply input.
Therefore it is recommended to insert a 10A fuse in the power supply cable near the power supply source
(e.g.: a battery) to avoid dangerous damage due to lightening event or to accidental short circuits along
power supply cables.
Internal power supply is not isolated. KAIROS must be supplied by an isolated power supply (from mains)
with a minimum isolation equal to the one of an IEC 61558-2-6 compliant safety transformer or equivalent.
The power supply input has the following characteristics:
Input Voltage
10.8
–
15.6 Vd
c, neg. ground, Nominal 13.
2
V
Max ripple
30 mVpp
Polarity reversal protection
up to
-
70 V
Power supply protections
Electronic protection with automatic restore for
overvoltage
and
undervoltage events
Short
-
circuit protection
Electronic protection with automatic restore
Power supply connector
2 pole model Phoenix Contact
Power consumption @160MHz
13.2Vdc – typical values for both DMR
timeslot used
Power off : 1mA
GPS Receiver (without
extern
al
antenna) : 30mA
LINUX & LAN
(no TRX active)
: 15
0mA