RKI Instruments Beacon 110 - Manual (Page 10)

6 Beacon 110 Operator’s Manual
Ground Stud
The threaded ground stud is used for making connections to earth ground. It is connected
through the main PCB to the G (ground) terminal on the AC in terminal strip. A kep nut on
the stud may be removed for installation of one or more lugs to make wiring connections.
This stud is typically used to connect the shield drain wire of shielded cable to earth
ground at the Beacon 110.
Relays
The Beacon 110 includes three alarm relays located above the alarm terminal strip. They
are from left to right Fail, Alarm 1, and Alarm 2. The relays are form C, single-pole, double-
throw (SPDT) and rated for 10 amps at 250 VAC (resistive).
NOTE: You can select normally energized (N.EN) or normally de-energized (N.DE-EN)
settings for the alarm 1 and alarm 2 relays. See “Chapter 5: Configuration
Mode” on page 26.
The fail relay is factory set as normally energized and is not user adjustable.
AC & DC Circuit Protection
Two AC fuses are used in the Beacon 110. The two fuses are located on the left side of
the main PCB, above the AC power terminal strip and below the power supply. They cut
off the incoming AC power in the event of a short circuit or other electrical fault which
causes a high current draw in the Beacon 110. They are housed in vertical fuse holders
and are held in the holder by a quarter turn cover. They are labelled as F1 (left fuse) and
F2 (right fuse) on the PCB silk-screen and are rated at 3 A, 250 V.
A polyswitch is used to protect the DC power input. It is located to the right of the relays
and is labelled on the PCB silkscreen as PS3. In the event of a short circuit or other
electrical fault which causes a high current draw in the Beacon 110, the polyswitch will
interrupt the DC power if the unit is powered from DC. When the fault situation is
corrected, the polyswitch resets and the unit will continue to operate. The polyswitch is not
user serviceable.
Power Switch
The power switch is located to the right of the power supply and above the relays (see
Figure 1). The power switch turns the incoming AC power source on and off at the Beacon
110. When the switch is up, the power switch is on.
CAUTION: The DC power input has no on/off switch and is not affected by the position
of the power switch.
Control PCB
The LCD display and control buttons are located on the control PCB. It is installed on the
main PCB with three standoffs. The control PCB is connected to the main PCB with the
display cable which is a ribbon cable terminated with 20 position rectangular connectors
on each end. The display cable connects to the control PCB on the back of the top edge
and to the main PCB directly below the control PCB.