Cheap DCC decoders


J

jweir43

New Member
I'd really like to populate my new layout with DCC for switches, lighting, and all the rest of it. I've been doing enough reading that I'm thoroughly confused on how the DCC protocol is sent down the rails.\

Is there a "DCC For Dummies" anywhere that I can refer to to completely understand the DCC signal ... including somebody that has decoded it and can give it as an example.

I'm not exactly a dummy in electronics; my MS is in EE and my life's work has been in RF and microwave communications. However, the DCC protocol has me totally bamfoozled. Any help would be appreciated.

Thanks,

Jim
 
jweir43 said:
I'd really like to populate my new layout with DCC for switches, lighting, and all the rest of it. I've been doing enough reading that I'm thoroughly confused on how the DCC protocol is sent down the rails.\

Is there a "DCC For Dummies" anywhere that I can refer to to completely understand the DCC signal ... including somebody that has decoded it and can give it as an example.

I'm not exactly a dummy in electronics; my MS is in EE and my life's work has been in RF and microwave communications. However, the DCC protocol has me totally bamfoozled. Any help would be appreciated.

Thanks,

Jim
Click to expand...
Three words.. Pulse Width Modulation PWM
 
ShermanHill said:
Three words.. Pulse Width Modulation PWM
Click to expand...
Rog on the PWM. Got that far. Also semi-understand the data stream, but such fundamental questions as "does the pulse train continue sending every data stream until it is shut off, does it do it once, does it do it ten times and then hope the decoder caught it", and simple questions like that are not answered. Neither does an oscilloscope examination of the waveform tell me much. Somewhere there is a guru ...
 
jweir43 said:
Rog on the PWM. Got that far. Also semi-understand the data stream, but such fundamental questions as "does the pulse train continue sending every data stream until it is shut off, does it do it once, does it do it ten times and then hope the decoder caught it", and simple questions like that are not answered. Neither does an oscilloscope examination of the waveform tell me much. Somewhere there is a guru ...
Click to expand...
My understanding is the pulse stream continues as long as the device is addressed. Differing addresses for each device.
 
jweir43 said:
I'd really like to populate my new layout with DCC for switches, lighting, and all the rest of it. I've been doing enough reading that I'm thoroughly confused on how the DCC protocol is sent down the rails.
Click to expand...
Why do you need digital protocol information to populate your layout with DCC?
Is there a "DCC For Dummies" anywhere that I can refer to to completely understand the DCC signal ... including somebody that has decoded it and can give it as an example.
Click to expand...
That sort of information would be in advanced DCC technical information not a generic DCC for dummies. I presume you have read the original NMRA specs.
https://www.nmra.org/sites/default/files/s-92-2004-07.pdf
 
JMRI offers a loconet monitor tool within it's free online software. With this display you can see the periodic poling of all items linked to the loconet. Any change in the throttle setting for the specific loco address will be displayed on the screen complete with throttle address, decoder address and the command. It can also be displayed with raw hex data as well.
 
D&J RailRoad said:
JMRI offers a loconet monitor tool within it's free online software. With this display you can see the periodic poling of all items linked to the loconet. Any change in the throttle setting for the specific loco address will be displayed on the screen complete with throttle address, decoder address and the command. It can also be displayed with raw hex data as well.
Click to expand...
I'm not sure how that would help me understand how to use DCC to throw a switch.

Jim
 
Did you look at this site? I found it very helpful when I started the DCC journey. I have it bookmarked for future reference as well. It starts at the beginning through advanced control. All the information you seek is out there for free, you just may have to search for it.

http://wiringfordcc.com/intro2dcc.htm
 
jweir43 said:
I'm not sure how that would help me understand how to use DCC to throw a switch.

Jim
Click to expand...
OK, we will use a Tortoise machine for this explanation. The Tortoise machine is a stall motor that will run on DC power so reversing its direction is just a matter of changing the polarity of the 12vdc applied to it.
Digitrax makes a board, SE8C which provides the 12 volts to the Tortoise machine and a set of contacts to reverse the polarity of the 12vdc. The SE8C can also be setup for data address of the 8 Tortoise machines that can be linked to the board. The Tortoise machine can then be addressed with your throttle to throw or close the turnout. The data address or the momentary contact can be used interchangeably to throw the turnout.
 
Pico scope, has the ability to decode the DCC packets. As far as wanting to control switches, lights, etc., take a look at LCC, (Layout Command Control). It runs on a hardwire network, and uses CANbus as the communications protocol.
 
Iron Horseman said:
Why do you need digital protocol information to populate your layout with DCC?
Click to expand...

This is the question, and it's answer that also I would ask, maybe in a slightly different way. Why do you believe it is necessary to have the information you seek in order to do what you want to do, on your layout? I'm quite sure that the vast majority of DCC users, even those who have full automation in use, would need that much intimate knowledge. If it was that complicated and demanded that sort of knowledge involvement, DCC control would have died a very quick death among hobbyist's. Why make it harder than necessary?
 
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