13.2.2 DC Units Second & Third Stage Tone
Selection
For units set up for –ve switching (default setting):
Stage two (S2) Operation
Power +ve and –ve, link a -
ve supply line to the S2
terminal.
Dip switch alters stage 2
tone.
Stage three (S3) Operation
Power +ve and –ve, link a -
ve supply line to the S3
terminal.
Dip switch alters stage 3
tone.
For units set up for +ve switching (refer to 13.3):
Stage two (S2) Operation
Power +ve and –ve, link a
+ve supply line to the S2
terminal.
Dip switch alters stage 2
tone.
Stage three (S3) Operation
Power +ve and –ve, link a
+ve supply line to the S3
terminal.
Dip switch alters stage 3
tone.
Fig. 6 DC Terminals
13.3 Stage Switching Polarity (DC Units
Only)
The BExS110D DC sounders have the facility to use either
+ve or –ve switching to change the tone to the second and
third stages. Negative switching is the default setting. For –ve
switching connect the two headers on the pcb to the left-hand
(marked –ve) and centre pins. For +ve switching connect the
headers to the right hand (ve) and the centre pins.
(Refer to Fig. 7)
Fig. 7 Stage Switching Polarity
13.4 Line
Monitoring
On BExS110D DC units, dc reverse line monitoring can be
used if required. All DC sounders have a blocking diode fitted
in their supply input lines. An end of line monitoring diode or
an end of line monitoring resistor can be connected across
the +ve and –ve terminals. If an end of line resistor is used it
must have a minimum resistance value of 3k3
Ω
and a
minimum power rating of 0.5 watts or a minimum resistance
value of 500
Ω
and a minimum power rating of 2 watts.
The resistor must be connected directly across the +ve and -
ve terminals as shown in the following drawing. The resistor
leads should be kept as short as possible.
Fig. 8 End of Line Resistor Placement
End of Line Resistor
Volume Control
DIP Switch
DC Terminals
Stage Headers
Negative Switching Activated
Positive Switching Activated
Header Pin Location
Header Pin Location
S2
S3
-
+
-
+
-
+
