dasatcopthorne Posted October 30, 2017 Share Posted October 30, 2017 Hi Guys. I've done the research on Diode Matix for point control and I have a diagram worked out. But How do I actually make it. What to use etc. I have the diodes, IN5404. Open to all suggestions but has anyone got pictures of what they have done please? Cheers Dave Link to post Share on other sites More sharing options...
Suzie Posted October 30, 2017 Share Posted October 30, 2017 I don't have any pictures, but double row tag board is favourite. Link to post Share on other sites More sharing options...
Butler Henderson Posted October 30, 2017 Share Posted October 30, 2017 (edited) 1N5404s are excessive for a diode matrix, there seems a great deal of confusion over diode numbering. You are right to pick one from the 1N5400 seris as they are 3 Amp didoes while the often used 1N4000 series are only 1 Amp. The last digit indicates the voltage the diode can handle, not as many think the current. Confusing they are numbered differently with the 3 Amps being numbered 1N5400 upwards but the 1 Amps 1N4001 upwards. A 1N5404 diode will handle 400 volts which I think will be an bit excessive for a point motor solenoid! You could use a 1N5400 which will handle 50 volts, (as will a 1N4001 in the 1 Amp range). There is nothing wrong however in using a diode of higher voltage capability. Edited October 30, 2017 by Butler Henderson Link to post Share on other sites More sharing options...
sdw7300 Posted October 30, 2017 Share Posted October 30, 2017 A photo on the one I built on Laoson Valley is here > http://www.rmweb.co.uk/community/index.php?/topic/76254-laoson-valley-1990s-to-modern-day-tmd-oil-terminal-p-way-yard/?p=1495535 Hope this helps Link to post Share on other sites More sharing options...
DCB Posted October 31, 2017 Share Posted October 31, 2017 (edited) Hi Guys. I've done the research on Diode Matix for point control and I have a diagram worked out. But How do I actually make it. What to use etc. I have the diodes, IN5404. Open to all suggestions but has anyone got pictures of what they have done please? Cheers Dave I can get some pics on Thursday as I can't find any this evening. I lay two ordinary connector block strips in parallel and stretch 1N400 diodes across between them, sleeving the bare wires and usually with careful design and using the small 3 amp blocks there is no need to solder anything. I just use plain insulated wire where back feed is not an issue. I tend to use multiple small matrix with common return and a single electric pencil control though I also use rotary switch selection with push button activation. It would be useful if you uploaded your diagram for comments. You may find CDUs struggle with multiple point motors, I never could see the point of CDUs so I just put a big 30 volt or more Electrolytic capacitor across the uncontrolled DC output of the transformer and bang 5 or 6 over at a time. The downside is I have to add extra point motor solenoids as "Dead Loads" so at least 4 solenoids are energised when for instance only a crossover really needs to be operated. Pics of a couple of my diode matrix modules now attached the modules are adjacent to the points there must be six of them but they have never given any trouble in 25 years so I tend to forget where they are! Edited November 8, 2017 by DavidCBroad 1 Link to post Share on other sites More sharing options...
gordon s Posted October 31, 2017 Share Posted October 31, 2017 (edited) Here one I built years ago when I used SMP/Peco motors. I used a similar schematic diagram and stood the diodes end on as that made it easier visually to see what went across to which terminal block. I'll have to dig out the diodes to see what they were. It was some time ago, but from the pic, I had the 12 inputs across the top and the separated the 'straight' and 'curved' directions out to each side. This was used to select a route for a 12 road fiddle yard. There's also an earlier thread here. http://www.rmweb.co.uk/community/index.php?/topic/72256-constructing-a-diode-matrix/ Edited October 31, 2017 by gordon s 1 Link to post Share on other sites More sharing options...
Chris M Posted October 31, 2017 Share Posted October 31, 2017 (edited) I've used the chocolate block connectors as well. Note that I have pasted wiring diagrams to the back of the back scene so I know which wires do what. The middle section was for connections to the next board. In the end I took the wires direct to the board connector so these didn't get used. I didn't update the wiring diagram so it isn't 100% up to date but it is extremely useful if anything stops working. I put everything on top of the baseboard to make for easy build and maintenance. I decided that was a lot of space not being fully used so I screwed a piece of board to the top to provide a loco storage facility. Edited October 31, 2017 by Chris M 1 Link to post Share on other sites More sharing options...
Jinty3f Posted October 31, 2017 Share Posted October 31, 2017 This one was built for my now defunct 00 gauge layout with 11 points. I designated each point road as either left or right, rather than straight. Chock blocks seemed the easiest way to make all the connections. The positive input went into the bottom track, through whichever set of diodes were needed for the route, and the negative was common. It was pretty reliable. HTH. 1 Link to post Share on other sites More sharing options...
dasatcopthorne Posted November 2, 2017 Author Share Posted November 2, 2017 Thanks for all your suggestions guys. I'm pressing on thanks to you all. Cheers Dave Link to post Share on other sites More sharing options...
RMweb Premium ColinK Posted November 3, 2017 RMweb Premium Share Posted November 3, 2017 Apologies if ots a daft question. But all my solenoid motors run off 16v AC. Diodes only pass current in one direction, so doesn't that mean that with a diode matrix, the solenoid motors only recieve DC? Link to post Share on other sites More sharing options...
Suzie Posted November 3, 2017 Share Posted November 3, 2017 Apologies if ots a daft question. But all my solenoid motors run off 16v AC. Diodes only pass current in one direction, so doesn't that mean that with a diode matrix, the solenoid motors only recieve DC? Yes, you either use a DC supply or A CDU when you have a diode matrix! Quite easy to make DC from AC with a bridge rectifier appropriately rated. Link to post Share on other sites More sharing options...
Chris M Posted November 3, 2017 Share Posted November 3, 2017 If you need a diode matrix you are normally changing a number of points at the same time. I have found you need a decent power CDU to successfully and reliably change a number of points at the same time. The AC feed goes to the CDU but the output from the CDU is DC so this works fine with the diode matrix. When current passes through a diode there is normally a small drop in voltage so again a CDU is important to give a good zap of power. Link to post Share on other sites More sharing options...
Ron Solly Posted November 3, 2017 Share Posted November 3, 2017 http://rail.felgall.com/dm.htm is one of many explanations. Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted November 4, 2017 RMweb Premium Share Posted November 4, 2017 http://rail.felgall.com/dm.htm is one of many explanations. For some reason, your links are failing. http://rail.felgall.com/dm.htm Link to post Share on other sites More sharing options...
Ron Solly Posted November 4, 2017 Share Posted November 4, 2017 Thanks Kevin I dunno why as it was copied from the URL bar http://rail.felgall.com/dm.htm Link to post Share on other sites More sharing options...
gordon s Posted November 4, 2017 Share Posted November 4, 2017 http://rail.felgall.com/dm.htm is one of many explanations. I suspect that as the underline is going beyond the last letter, it is including a space and corrupting the address. Link to post Share on other sites More sharing options...
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