5
3.0 Track Wiring for Detection with BDL16
BDL16 comes from the factory set up for DCC operation on layouts that use
direct home wiring. Direct home wiring is the wiring method recommended by
Digitrax. With direct home wiring, each power district and its booster is elec-
trically isolated. This method of wiring has safety advantages and makes detec-
tion work more prototypically. The track within each power district can use
"common rail" wiring for detection or power management. In most cases, the
BDL16 will work as it comes from the factory with direct home wiring when
its 44 pin socket is wired to the layout and connections are made to a 12V AC
power supply (100mA minimum), booster power and ground. Figure 1:
Typical Direct Home Wiring, shows the typical usage of a BDL16 operating
all 4 zones from a single booster, i.e. in a single power district. A single
BDL16 can be operated by up to four different boosters.
With direct home wiring, the BDL16 can determine & indicate whether any of
its 4 zones is powered or not (possibly short-circuited) even when there is noth-
ing on the rails in the detection sections. The BDL16 default logic causes the
detection sections to show "occupied" if the associated zone's power is off
(because in this case, detection is not possible). This default matches prototype
detection safety practices.
Whole layout common rail is a method of wiring layouts where power districts
and their boosters are electrically connected using a common rail or common
power bus return wire. Whole layout common rail wiring is at a disadvantage
when it comes to detection systems since detectors cannot independently moni-
tor whether zone power is on or off so they can't tell whether occupancy detec-
tion is working or not in any given detection section. To get around this limita-
tion, the BDL16 uses option switch 10 to set up detection section 16 to be used
as a zone power detector for detection sections 1 through 15. Wire a 10K resis-
tor from detection section 16 (not connected to tracks) to the detection common
return for the whole BDL16. Then detection section 16 on the BDL16 will be
active when the BDL16 sees track power and you will be able to tell whether
detection is actually available in detection sections 1 through 15.
4.0 BDL16 Installation
TABLE I shows the pin-out for the BDL16's 44 pin connector. Be sure to wire
the BDL16 ground wire to the Digitrax Booster ground, common (or case) of
the boosters. Wire the track outputs to the appropriate detection section follow-
ing the example in Figure 1. The Zone common connections to the booster
should be as short as possible and relatively heavy gauge, since they are com-
mon to all four detectors in the zone. For example, a 12awg zone connection to
the booster should be less than 10 feet for best performance. For whole layout
4
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1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
2
0
2
1
2
2
T
OP R
O
W
A
B
C
D
A
UX1
A
UX2
PS12
12 VAC
Power
Supply
Zone Common
(Heavy Wire)
Detection Common
Booster Ground to pin 11
Zone A
DS 1
DS 2
DS 3
DS 4
Zone B
DS 5
DS 6
DS 7
DS 8
Zone C
DS 9
DS 10
DS 11
DS 12
Zone D
DS 13
DS 14
DS 15
DS 16
Booster GND
Ext. Power
BDL16
Top View
Detection Section
1
Detection Section
2
Detection Section
3
Detection Section
4
T R A C K
S T A T U S
P O W E R
O N
O F F L I N E
O / G
N
H O
M O D E
M O D E
O
R U N
L O C O N E T
A
B
S C A L E
S L E E P
S L E E P
P
P
R
R
RAIL B
POWER INPOWER IN
RAIL A
POWER INPOWER IN
GROUND
LocoNet
to other LocoNet
Devices such as
(Throttles, Boosters,
UP3's Etc.)
12
V
A
C to Pin 12
12
V
A
C to Pin N
Note: BDL16 Zone A Wiring
shown for clarity. Zones B, C,
and D are wired similarly.
External LED
Connectors (pin 1)
(See
Figure 4)
Figure 1: Typical Direct Home Wiring
Direct Home Booster (Digitrax standard)
ID LED (green)
Option LED (red)
Detection Section
16
~
~
~
~
