User's Manual

Radio Activity S.r.l. 22 / 44
PPS to rear plug
Internal ref
Internal ref
KAIROS “B” and “C”:
Slave
Master
1
st
choice
External PPS (full)
External PPS (full)
2
nd
choice
Internal ref (full)
Internal ref
(full)
3
rd
choice
Internal ref (full)
Internal ref (full)
4
th
choice
Internal ref (full)
Internal ref (full)
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.