Block Occupancy Detector BOD1-BR

BLOCKsignalling BOD1-BR Block Occupancy Detector for Model Railways

Detects Traction Current from Trains Running on a Track Section

  • Monitors the track current for the movement of trains
  • When a train is detected operating on the track, the module runs one of the built-in programs
  • Able to operate control panel lights, 2-aspect signals, or to trigger other modules
  • Programmable options to vary the operation of the module


This Block Occupancy Detector recognises the current drawn by moving trains within a block, and can operate a number of built-in programs in response.

When used with DC systems, the detector can indicate the direction of trains in a block. The detector can also be wired to operate remote indications on a control panel or to operate 2-spect light signals.

With DCC systems, the detector indicates the presence of one or more trains in a block, but cannot determine the direction of those trains.

The in-built programs are as follows:

Programme 1 - Lamp Test
Programme 2 - Single Pulse output, train direction not considered
Programme 3 - Single Pulse output, train direction considered
Programme 4 - Multi Pulse output, train direction not considered
Programme 5 - Multi Pulse output, train direction considered
Programme 6 - Constant output whilst train moving, train direction not considered
Programme 7 - Constant output whilst train moving, train direction considered
Programme 8 - 2-aspect signal output, train direction considered

Power Supply

The module operates from any DC power supply between 8V and 25V DC, or any AC power supply between 8V and 16V AC.

Where a choice is a available, a 12V DC supply is recommended.

Please double check all wiring before applying power, as incorrect wiring can damage the unit.

 

Output connections

There are two outputs available which are floating (they are not internally connected in the module to either the 12V supply or ground).

They can be used to switch 12V to leds, by connecting C1 or C2 to the +12V terminal, or they can be used to make a connection to ground, by linking E1 or E2 to the ground terminal.

Wire links are shown in the diagrams following to make this clear.

Block Detector Connections

 

Programming

Programming for the particular application can be completed before or after testing the wiring, and also before or after completing the installation.

This is performed by holding down the Push Button when switching on the power.

DCC Block Occupancy Detector

 

For each program there are two values to be stored.

The red led on the PCB flashes at 1 second intervals. When the required number of flashes is seen (see later for the list of possible choices) the button is released to store the first value. At this point the led comes on for five seconds to confirm the value is stored.

The led then starts flashing again, and this time the button needs to be pressed to store the second value.

Once both values have been are entered, the led flashes 10 times rapidly, and the module starts operating.

Each value entered can be up to 255 flashes. If more are seen, or the programming is aborted by switching off, then the programming must be repeated.

 

Factory Reset

To reset the module back to factory default settings, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 1 flash of the led is seen. At this point, release the button. You will see a long flash of five seconds.

The led will begin flashing again. When you have seen 1 flash press the button. You will see a long flash of five seconds and then 10 rapid flashes. The reset procedure is then complete and the module will restart with factory settings, and run the lamp test mode. If you make a mistake programming, simply repeat the process.

Program 1 – Lamp Test Mode

This is a test program to switch the output channels in a set sequence and may be set when the unit is supplied.

Block Occupancy Detector Directional

 

In this sequence, first all outputs are on, then they all go off except ch1. Then ch1 is switched off and ch2 comes on, then all the outputs are switched off and the sequence is repeated. Each step takes 1 second. The led on the PCB switches on and off with each step.

When supplied, or following a factory reset, the module will operate in lamp test mode. It can be also be switched to this mode at any time as follows:

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes are seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 1 flash has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the lamp test program.  Other settings will be retained.  If you make a mistake programming, simply repeat the process.

 

Program 2 - DC/DCC Train In Block Indication, Single Pulse Output (Direction Insensitive)

This program switches both outputs briefly whenever there is a train enters a block.

The time taken to detect a train, and the duration of the output switching on are adjustable (see later).

The default values are 250ms to detect a train and then switch on the output for 1 second.

This process will not repeat until the train has been absent from the section for the release time, and the post-release delay time.

It works equally well for DCC or DC installations and trains traveling in either direction will trigger the module.

 

Block Occupancy Detector for DCC

Block Occupancy Detector for DCC

Block Occupancy Detector for DCC

 

When supplied, or following a factory reset, the module will operate in lamp test mode. It needs to be reprogrammed to operate program 2 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes are seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 2 flashes have been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

Program 3 - DC Train In Block Indication, Single Pulse Output (Direction Sensitive)

This program lights an led, whenever there is a train enters a block.

On DC layouts, the direction of the train will be detected, and the appropriate output switched on. If used for DCC, both leds will light at the same time when a moving train is detected.

The time taken to detect a train, and the duration of the output switching on are adjustable (see later).

This process will not repeat until the train has been absent from the section for the release time, and the post-release delay time.

The default values are 250ms to detect a train and then switch on the output for 1 second.

 

Block Occupancy Detector for DCC

Block Occupancy Detector for DCC

Block Occupancy Detector for DCC

 

When supplied, or following a factory reset, the module will operate in lamp test mode. It needs to be reprogrammed to operate program 3 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes is seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 3 flashes has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

 

Program 4 - DC/DCC Train In Block Indication, Multi-Pulse Output (Direction Insensitive)

This program switches both outputs briefly whenever there is a train moving within a block.

The time taken to detect a train, and the duration of the output switching on are adjustable (see later).

The default values are 250ms to detect a train and then switch on the output for 1 second. If the train remains on the line, this process will repeat, resulting in the leds flashing (1 second on/250ms off).

It works equally well for DCC or DC installations and trains traveling in either direction will trigger the module.

 

When supplied, or following a factory reset, the module will operate in lamp test mode.  It needs to be reprogrammed to operate program 4 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes is seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 3 flashes has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

 

Program 5 - DC Train In Block Indication, Multi-Pulse Output (Direction Sensitive)

This program lights an led, whenever there is a train moving within a block.

On DC layouts, the direction of the train will be detected, and the appropriate output switched on. If used for DCC, both leds will light at the same time when a moving train is detected.

The time taken to detect a train, and the duration of the output switching on are adjustable (see later).

The default values are 250ms to detect a train and then switch on the output for 1 second. If the train remains on the line, this process will repeat, resulting in the leds flashing (1 second on/250ms off).

 

When supplied, or following a factory reset, the module will operate in lamp test mode.  It needs to be reprogrammed to operate program 5 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes is seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 5 flashes has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

 

Program 6 - Train In Block Indication with Delayed Release (Direction Insensitive)

This program is similar to programme 2, but the outputs remain switched whilst the train is in the section.

The direction of the train is not detected.

The default time taken to detect a train is 250ms.

Whilst the train travels through the section, the output will continue to be switched on. Once the train exits the section, after a delay (default 4 seconds), the output is switched off. This is the post-release delay setting.

So that small breaks in track current, due to poor contact of the train with the rail due to dirt or corrosion, do not cause the module to falsely trigger, the above delay will not start until the current has stopped for 1 second (the release time).

The trigger time, release time, and post-release delay are adjustable.

 

When supplied, or following a factory reset, the module will operate in lamp test mode. It needs to be reprogrammed to operate program 6 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes is seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 6 flashes has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

 

Program 7 - Train In Block Indication with Delayed Release (Direction Sensitive)

This program is similar to programme 3, but the outputs remain switched whilst the train is in the section.

This program lights an led, whenever there is a train moving within a block.

The default time taken to detect a train is 250ms.

On DC layouts, the direction of the train will be detected, and the appropriate output switched on. If used for DCC, both leds will light at the same time when a moving train is detected.

Whilst the train travels through the section, the output will continue to be switched on. Once the train exits the section, after a delay (default 4 seconds), the output is switched off. This is the post-release delay setting.

So that small breaks in track current, due to poor contact of the train with the rail due to dirt or corrosion, do not cause the module to falsely trigger, the above delay will not start until the current has stopped for 1 second (the release time).

The trigger time, release time, and post-release delay are adjustable.

 

When supplied, or following a factory reset, the module will operate in lamp test mode. It needs to be reprogrammed to operate program 7 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes is seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 7 flashes has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

 

Program 8 - 2-Aspect Signal Operation (Direction Sensitive)

This program is designed to operate a 2-aspect light signal on a DC layout. It will also operate on a DCC layout, providing trains only approach the signal from the front direction.

The signal normally operates at Green (Clear).

When a train enters the section (from the correct direction), the signal will change to Red (Danger). The default time taken to detect a train is 250ms.

If the train remains on the line, the signal will stay at Danger. Once the train exits the section, after a delay (default 4 seconds), the output will be switched back to Clear (Green). This is adjustable with the post-release delay setting.

So that small breaks in track current, due to poor contact of the train with the rail due to dirt or corrosion, do not cause the module to falsely trigger, the above delay will not start until the current has stopped for 1 second (the release time).

The trigger time, release time, and post-release delay are adjustable.

 

Block Occupancy Detector for DCC

 

When supplied, or following a factory reset, the module will operate in lamp test mode. It needs to be reprogrammed to operate program 8 as follows.

To select this program, switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 2 flashes is seen. At this point, release the button. You will see a long flash of two seconds and then the led will begin flashing again.

When 8 flashes has been seen press and hold the button. You will see a long flash of five seconds and then 10 rapid flashes. The button can now be released and the programming is complete. The module will start running the program. If you make a mistake programming, simply repeat the process.

 

Output Waveforms

The diagrams below show the state of the outputs for each of the programs, when a train is traveling through a section (a high level pulse indicates the output is conducting, and so the led will be lit).

The Release Time and the Post Release Delay have to expire before the module can be re-triggered.

DC layout is assumed (on DCC both outputs will be identical to the first trace for each program).

 

Block Occupancy Detection Diagram

 

Absolute Block Occupancy Detection

 

Absolute Block Occupancy Detection

 

Adjusting the Trigger Time

The time taken to register the presence of a train on the track is adjustable in steps of 50ms. By changing the trigger time, the duration for which the train must be present before triggering the module can be adjusted.

The default time is set to 250ms, by setting parameter 3 to a value of 5 (5 x 50ms = 250ms).

This value is adjustable from 1 to 255 by setting parameter 3 to the number of 50ms steps required. So, if it is required the train to be present for half a second (500ms) before it is detected, then set this parameter 3 to a value of 10.

Do not set a figure too high, as dirt on the track and poor contact could result in trains not being detected.

The full procedure is as follows:

Switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 3 flashes of the led are seen. At this point, release the button. You will see a long flash of five seconds.

The led will begin flashing again. When you have seen 10 flashes (or other duration you wish to set) press the button. You will see a long flash of five seconds and then 10 rapid flashes. The programming is then complete and the will start running the program. If you make a mistake programming, simply repeat the process.

 

Adjusting the Release Time

When a train passes over the track, the current flow can be briefly interrupted by dirt on the track, or poor contact of the train pickup on its wheels. These brief breaks in the current flow could be recognised as the train leaving the block, when in fact this is not the case.

The module is set to ignore breaks in the current flow for up to 1 second, before registering the train having left the section. This value (the Release Time) can be adjusted to cover longer breaks, before registering the block as clear.

This delay is adjustable from 1 to 255 seconds by setting parameter 4 to the number of seconds required. So, if it is required the current be absent for 7 seconds before it is confirmed the train has fully cleared the section, then set this parameter to 7.

The full procedure is as follows:

Switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 4 flashes of the led are seen. At this point, release the button. You will see a long flash of five seconds.

The led will begin flashing again. When you have seen 7 flashes (or other duration you wish to set) press the button. You will see a long flash of five seconds and then 10 rapid flashes. The programming is then complete and the will start running the program. If you make a mistake programming, simply repeat the process.

 

Adjusting the Pulse Duration

In programs 2 and 3, pulsed outputs are produced when a train is detected.

The duration of the pulse is adjustable in 250ms steps, with 1 second (1000ms) being the default. This is set using parameter 5, which is set to 4 as the default (4 x 250ms = 1000ms).

If you wish to change the pulse time to say, 500ms, the full procedure is as follows:

Switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 5 flashes of the led are seen. At this point, release the button. You will see a long flash of five seconds.

The led will begin flashing again. When you have seen 2 flashes (or other duration you wish to set) press the button. You will see a long flash of five seconds and then 10 rapid flashes. The programming is then complete and the will start running the program. If you make a mistake programming, simply repeat the process.

 

Adjusting the Post-Release Delay

Once the train has been detected as having left the section, there is a further delay before the outputs are switched back to their un-triggered state (to allow all carriages to clear a section for instance). This is adjustable using the post-release delay (parameter 6) which is adjustable in 1 second steps and has a default of 4 seconds.

If you wish to set the post-release delay to 5 seconds, the full procedure is as follows:

Switch off the power to the module and hold down the Push Button. Apply the power and continue holding the push button until 6 flashes of the led are seen. At this point, release the button. You will see a long flash of five seconds.

The led will begin flashing again. When you have seen 5 flashes (or other duration you wish to set) press the button. You will see a long flash of five seconds and then 10 rapid flashes. The programming is then complete and the will start running the program. If you make a mistake programming, simply repeat the process.

Programming Flow Diagram

The following diagram shows the programming options available.

Block Occupancy Detector Programming