Model Railroad Control Systems
Model Railroad Control Systems

MRCS-odTester

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A simple bench test board for Chubb\'s DCC-OD and MRCS\' cpOD detectors.

 

 

MRCS-odTester Version 2.1

Not built

Test and tune Occupancy Detectors on your workbench for low, normal or high sensitivity

Version 2.0:

  • Make the resistors pads 0.400 across. The standard red triangular benders only go down to 0.400 so bending to 0.300 requires doing it manually.
  • Made the 100uF a 3.5x10 package to match what is in stock…
  • Fixed silk screen TRACK and DCC
  • Boxed the LOW and NORMAL buttons to indicate that they both chould trigger, and the HIGH one should not

Schematic
Schematic
Bot Silk
Bot Silk
Board
Board
Top Silk
Top Silk

Download MRCS-odTester - CHMT Component and feeder definitions
Download MRCS-odTester.gerbers.zip - Gerber Fabrication files
Download MRCS-odTester.parts - Parts List (spreadsheet data)

 

MRCS-odTester.bom

Parts Value Package Quantity Library Type/Feeder
C2 0.1uf C050-024X044 1x SPCoast PTH
R4 2k AXIAL-0.4-RES 1x SPCoast PTH
R3 5k AXIAL-0.4-RES 1x SPCoast PTH
R2 10k AXIAL-0.4-RES 1x SPCoast PTH
R1 100k AXIAL-0.4-RES 1x SPCoast PTH
C1 100uF E3.5-10 1x SPCoast PTH
U$1 +12v PWR_LABEL 1x SPCoast PTH
SW1, SW2, SW3   B3F-10XX 3x SPCoast PTH
CON1   DCJ0202 1x SPCoast PTH
DCCOD   KK-156-5 1x con-molex PTH
LED1   LED5MM 1x SPCoast PTH
DCC, TRACK   MSTB2 2x SPCoast PTH
BOARD1 BOARD50X50 BOARD-SEEED5X5 1x SPCoast PTH

MRCS-odTester Version 2.0

Not built

Test and tune Occupancy Detectors on your workbench for low, normal or high sensitivity

Version 2.0:

  • Make the resistors pads 0.400 across. The standard red triangular benders only go down to 0.400 so bending to 0.300 requires doing it manually.
  • Made the 100uF a 3.5x10 package to match what is in stock…
  • Fixed silk screen TRACK and DCC
  • Boxed the LOW and NORMAL buttons to indicate that they both chould trigger, and the HIGH one should not

Schematic
Schematic
Bot Silk
Bot Silk
Board
Board
Top Silk
Top Silk

Download MRCS-odTester - CHMT Component and feeder definitions
Download MRCS-odTester.gerbers.zip - Gerber Fabrication files
Download MRCS-odTester.parts - Parts List (spreadsheet data)

 

MRCS-odTester.bom

Parts Value Package Quantity Library Type/Feeder
C2 0.1uf C050-024X044 1x SPCoast PTH
R4 2k AXIAL-0.4-RES 1x SPCoast PTH
R3 5k AXIAL-0.4-RES 1x SPCoast PTH
R2 10k AXIAL-0.4-RES 1x SPCoast PTH
R1 100k AXIAL-0.4-RES 1x SPCoast PTH
C1 100uF E3.5-10 1x SPCoast PTH
U$1 +12v POWER_USAGE 1x SPCoast PTH
SW1, SW2, SW3   B3F-10XX 3x SPCoast PTH
BOARD1   BOARD-SEEED5X5 1x SPCoast PTH
CON1   DCJ0202 1x SPCoast PTH
DCCOD   KK-156-5 1x con-molex PTH
LED1   LED5MM 1x SPCoast PTH
DCC, TRACK   MSTB2 2x SPCoast PTH

MRCS-odTester Version 1.1

Not built

Test and tune Occupancy Detectors on your workbench for low, normal or high sensitivity

V1.1: external DCC source connector as well as external test track for testing rolling stock

Schematic
Schematic
Bot Silk
Bot Silk
Board
Board
Top Silk
Top Silk

MRCS-odTester Version 1.0

First built: 2017-01

V1.0: No provision for external DCC signal source

Schematic
Schematic
Bot Silk
Bot Silk
Board
Board
Top Silk
Top Silk

Documentation

DCCOD Detector Tester

A simple bench test board for Chubb's DCC-OD and MRCS' cpOD detectors.

Theory:

This board is designed to be a bench test unit for Chubb's DCCOD style detectors. A board is inserted into the test pins and the three buttons are pressed in sequence while observing the "detected" LED. A "good" board will light up with both the "low" and "normal" button presses, but not the "high" one. The DCCOD sensitivity can be adjusted in the jig to give the desired behavior.

A local test track can be optionally connected that enables the testing of specific locomotives and rolling stock simply by placing them on the track.

The values for R1, R2 and R3 should be chosen for the layout and locomotives in use - N-scale's small highly efficient motors will draw less current than a O- or G-scale, and will require greater sensitivity. Your wheelsets may provide 10K or 100K resistors, which should also inform your choices. The values below are astarting point; feel free to experiment. There is nothing wrong with choosing 100K as "normal" and 150K as "too high" as long as your choice of "turns" thru the DCCOD's pulse transformer can provide the detection. Start with "normal" matching your wheelset/rolling stock resistors, "low" being half of that, and high being 2x to 10x of normal...

Validate that your DCCOD can actually detect your chosen values by adjusting its potentiometer to its mose sensitive position and observing that the detected LED lights when the buttons are pressed.

Usage:

  • Plug a DCCOD board to the DetectorTester.
  • Connect to a 12v DC regulated power supply.
  • Connect the output of a DCC booster to the DCC connector
  • Press one of the pushbuttons to place a detectable load resistance across the simulated "track" for the detector to see - Sensitivity test values (choose to match your givens and druthers) - 5K resistance (~3mA) - 10K resistance (~1.5mA) - 100K resistance (~0.15mA) - 150K resistance (~0.1mA)

Use the following table to diagnose/adjust based on the whether the detection LED lights when the following buttons are pressed:

LOW NORMAL HIGH  
OFF OFF OFF Nothing lights, missing DCCOD, no DCC power, no DC power, poorly chosen R1,R2 and R3
OFF OFF ON Bad detector tester - check solder connections
OFF ON OFF Bad detector tester - check solder connections
OFF ON ON Bad detector board - check solder connections
ON OFF OFF this DCCOD will have problems detecting a typical car resistance. Adjust DCCOD until NORMAL lights when pressed
ON OFF ON Bad detector tester - check solder connections
ON ON OFF this DCCOD is properly adjusted
ON ON ON this DCCOD is potentially overly sensitive, and may false trigger. Lower the DCCOD sensitivity until this just extinguishes

If any of the LEDs light when no buttons are pressed and nothing is connected to the external track connector, either the detector tester or the DCCOD is bad.

doc

DCCOD Detector Tester

A simple bench test board for Chubb's DCC-OD and MRCS' cpOD detectors.

Theory:

This board is designed to be a bench test unit for Chubb's DCCOD style detectors. A board is inserted into the test pins and the three buttons are pressed in sequence while observing the "detected" LED. A "good" board will light up with both the "low" and "normal" button presses, but not the "high" one. The DCCOD sensitivity can be adjusted in the jig to give the desired behavior.

A local test track can be optionally connected that enables the testing of specific locomotives and rolling stock simply by placing them on the track.

The values for R1, R2 and R3 should be chosen for the layout and locomotives in use - N-scale's small highly efficient motors will draw less current than a O- or G-scale, and will require greater sensitivity. Your wheelsets may provide 10K or 100K resistors, which should also inform your choices. The values below are astarting point; feel free to experiment. There is nothing wrong with choosing 100K as "normal" and 150K as "too high" as long as your choice of "turns" thru the DCCOD's pulse transformer can provide the detection. Start with "normal" matching your wheelset/rolling stock resistors, "low" being half of that, and high being 2x to 10x of normal...

Validate that your DCCOD can actually detect your chosen values by adjusting its potentiometer to its mose sensitive position and observing that the detected LED lights when the buttons are pressed.

Usage:

  • Plug a DCCOD board to the DetectorTester.
  • Connect to a 12v DC regulated power supply.
  • Connect the output of a DCC booster to the DCC connector
  • Press one of the pushbuttons to place a detectable load resistance across the simulated "track" for the detector to see - Sensitivity test values (choose to match your givens and druthers) - 5K resistance (~3mA) - 10K resistance (~1.5mA) - 100K resistance (~0.15mA) - 150K resistance (~0.1mA)

Use the following table to diagnose/adjust based on the whether the detection LED lights when the following buttons are pressed:

LOW NORMAL HIGH  
OFF OFF OFF Nothing lights, missing DCCOD, no DCC power, no DC power, poorly chosen R1,R2 and R3
OFF OFF ON Bad detector tester - check solder connections
OFF ON OFF Bad detector tester - check solder connections
OFF ON ON Bad detector board - check solder connections
ON OFF OFF this DCCOD will have problems detecting a typical car resistance. Adjust DCCOD until NORMAL lights when pressed
ON OFF ON Bad detector tester - check solder connections
ON ON OFF this DCCOD is properly adjusted
ON ON ON this DCCOD is potentially overly sensitive, and may false trigger. Lower the DCCOD sensitivity until this just extinguishes

If any of the LEDs light when no buttons are pressed and nothing is connected to the external track connector, either the detector tester or the DCCOD is bad.

This technical documentation is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike