This block detector has four inputs to get power from up to four different power sources (boosters or PM42 outputs). Each input services four outputs, called a zone. With four inputs each having four outputs each, it provides block detection for 16 blocks.

The BDL162 sends block occupancy messages via LocoNet as well as having direct output in the form of low-current LED drivers. Signaling can be done via LocoNet or other systems requiring direct connection to the block detector. To control anything but low-current LEDs from the direct connection output requires an opto-isolator with amplifier..

Within the direct output connector is a zone-power indicator for those four blocks. This can be used as a fascia track- power indicator.

Current sensing is accomplished with the use of diodes - current drawn through the diodes causes a voltage drop which can be detected. While locos and lighted passenger cars will draw more than enough current to be detected, a freight car will need a maximum of 22K ohms resistance across the rails. Less will do. Sensitivity of the BDL162 can be decreased to require more current to be drawn, with a maximum of 10K ohms, to activate it. Additional wiring can be done to decrease sensitivity even more.

The BDL162 can handle one RX4 Transponding receiver. Original plans were to allow up to two, but technical difficulties have limited that. This limits each BDL162 to four Transponding zones. However, wiring the RX4 for variations of Transponding zones is so versatile it almost doesn't matter. Click here for more information.

The BDL162 requires 100 mA of current. Multiple BDL16s can draw power from the same power source as long as that power source can provide enough power for everything connected to it. They must not be connected to the same source that is powering anything else. Our UPT and Digitrax's PS12 provide 200 mA, so they can power up to two BDL162s.

The BDL162 comes with a Card Edge Connector. The BDL162 board is slotted for a card edge connector key, but a key does not come with BDL162s.

The BDL162 is limited to about 3 amps per detection block - not because of part limitations, but because of heat dissipation. This usually isn't a problem unless you're running high-current equipment such as American Flyer, Lionel, O, or G-Scales. If you find your BDL162s getting excessively hot, you may want to add heat sinks.

Once made, sandwich it between the two rows of bridge rectifiers and secure with four #6 machine screws and nuts. The screws need to hold the rectifiers tight to the heat sink, but not so tight it breaks them. If you have some heat sink paste, a little between the heat sink and rectifiers won't hurt.

Components are rated at 10 amps. But because there is no heat transference metal on the rectifiers, we cannot say how much extra current this will allow without overheating. If you feel more heat dissipation is needed for your situation, you can make two more of these to place on the outside sides of the rectifiers.