Monday, March 2, 2015

February Update

This is my first post for 2015.  In January Kaye & I went to Melbourne to see the the stage show Grease after which we spent New Year with Peter (the owner of Brownsville) returning home in time to move her home after she worked in the country for over a decade.

Well I did get some hobby time which was used to do some more design work on the signal system. I discovered a flaw in my thinking..  I was going to share inputs from Block Detectors and Turnouts positions into each control module via optocouplers - the practice of putting diodes in parallel (the diodes inside the optocouplers) is NOT good practice... and WILL lead to spurious results...  back to the drawing board....  I had a nervous time when in away packing my wife's stuff to come back home too.

I have settled on the connectors and configuration of wires for the photo-transistors used for direction sensing and those used for signal masts.

Pierre rang early in January to organise another training session but the hobby activities have been impacted as the area we use (Huntington) is stacked with stuff from the house move!  Well the session happened in the third week of February.

Just after the training session I caught bronchitis and that shut me down from doing anything much for the rest of February.

Review of Signal System Components 

It had to go back and look at all the components to ensure the "diodes in parallel" was eliminated.. So changes to the Dual Block Direction Sensor (DBDS) and the Standard Signal Control Modules (SSCM) were required.  Basically it was a "good mistake" as it has lead to a reduction in electronic components and simplification of some circuits.  The key points were remote sensing and signal masts will run at 12V and all the control signal modules utilising "control signals" will be at 3.3V.

Control Panel modifications for Sharing Inputs

Integrating the control strategy into existing control panels.

Dual Block Direction Sensor (DBDS)

Minor changes 2 Optocouplers on inputs removed and replaced by 2 Pin Headers 
Block Detector inputs removed from 12V and now direct connect to micro controller pin at 3.3V

Standard Signal Control Module

The production prototypes for the "shared inputs to Optocouplers" versions has arrived. I will need to modify them for testing purposes as the new production version has been ordered.

Optocouplers on inputs removed and replaced by 2 Pin Headers and previously unused pins connected to allow programming flexibility to account for turnouts on the passing loop and other programmable eventualities.

Junction Control Module

Previously the prototype was on a breadboard.

I designed a new PCB and the production prototype has been ordered.

Input Isolation Module

Given the need to consolidate all block and turnout states into manageable groups I have designed a module that has two blocks of 10 inputs per PCB.  Inputs have a protection diode, a LED (shows input active) then Optocoupler in series so the existing current draw from the boosters through the control panel remains constant albeit the panel LED's will dim slightly.

Integrating the System Components

I have started laying out the required components on a base board to see "how it will all fit together".

Standard Wiring Terminations

RJ45 - 8 Pin Header - 8 Screw Terminal

8 Conductor flat cable

Defining 8 wire connections

Signal Head Feeders

Cable Termination

Cable Terminations

Signal Heads

Standards developed for signal head connections - two options 1: separate signal masts & 2: dual head signal mast.

DBDS Phototransistors

A Nervous Time

Whilst I was away packing up my wife's flat in the country and when I was getting ready for bed.... Security monitoring rings to tell me the smoke detector in the train room has activated and did I want them to send the fire brigade? Well that is why we have these systems so ... "Yes"... I tell them to let the fire brigade know to contact me so I can give details to gain access as I am about 300 km from home....

Apparently it has been one of those nights and all fire units in my and the three surrounding areas are all "called out" so my fire truck is coming from the City HQ some 20 km away...  I must say I was impressed...  I had the scanner running and whilst I missed the dispatch I heard the arrival and within 30 seconds of hearing "... arrived nothing showing" my mobile rang with Station Officer X wishing to talk to me. A very efficient gentleman Instructions on key safe location, code, key access, which door, light switch location, entry to train room & found smoke detector activating but luckily no smoke or flames....

Talked through security system settings and they secured the premises and reset alarms before leaving. Not once did I have to repeat any information. What I said was acted on immediately and accurately. It would appear that either the abnormal high humidity was to blame.

Well none of the other three smoke detectors were affected so I deiced it was time to seal off the garage like every other room in the house.  he work began today.  Below are a few photos and a big thanks to Ross and Rosslyn for what got done today.

That's it for this month.

Till the end of March 2015.


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