BlocD8 - DCC Block
Detector Application Information
Block
Detector:
The BlocD8 can be used in a stand-alone mode or in a
network with other devices.
It is designed to sense high frequency DCC
AC current and will not work with DC current or 60 cycle
AC current.
Sensitivity Issues:
There are several reasons why the BlocD8 may indicate a
block is occupied when in fact there is no engine or
rolling stock in the block. If there is a LED or some
kind of indicator that is powered from the track, this
could cause the BlocD8 to show occupied. High humidity
conditions can cause a problem. Perhaps the ballast
is damp for some reason. Water can act like a resistor
between the rails. There can be enough distributed
capacitance in the DCC wires to cause a small amount of
current to flow and thus causing a false indication. To
keep the capacitance to a minimum, keep the the block
feed wire or any of the block track feeder wires from
running right next to other wires for long distances. Do
not twist the block feed wire with another wire.
The BlocD8 has two potentiometers to adjust sensitivity.
Turning the pot CCW will increase the sensitivity. If the
pot is turned fully CCW there may be false block
detection. Passing the feed wire through each sensor two
times will increase the sensor output and allow the
sensitivity pots to be adjusted (less sensitive) to make
the over all sensitivity the same. This scheme will cause
the BlocD8 to be less susceptible to false indications
due to wire routing near the BlocD8. This will not solve
problems due to issues mentioned above.
Wiring:
See a picture for suggested block
wire routing and connection to the BlocD8.