Jump to content
 

Reverse engineering the NCE cab bus using the PowerCAB


Recommended Posts

Shouldn't be a problem. Each cab/throttle has its own address and only responds when the controller polls that address. The controller remembers the state of each cab/throttle separately, so will associate each key press as it happens with the correct cab/throttle.

  • Agree 1
Link to post
Share on other sites

  • RMweb Premium
On 28/07/2021 at 08:40, Ron Ron Ron said:

 

 

The NCE system was first introduced (as the Wangrow System One) in 1994.

27 years ago.

 

 

And there is a poor guy on Freiwald Forum trying to get a Wangrow and some occupancy detectors of the same period working with a new PC!

 

  • Friendly/supportive 1
Link to post
Share on other sites

On 31/07/2021 at 09:23, DonSn35Quixote said:

This  suggests the Cab06 replies to a ping from CMD with Select (49H) the a series of digits from button presses with the sequence ended with Enter (40H).  That is not a two byte response, and is not mentioned in any documentation I have uncovered. Hopefully this will be helpful to anyone working on a project involving the NCE Cab Bus.  I intent to take the Irish approach (To be sure, to be sure to be sure) and confirm this advice by testing.

 

I suspect that your Cab06 will behave as described in the NEC bus protocol: keycodes will not be sent in a group; there are no responses other than the documented 2- and 5-byte response.

 

Most likely, your select-loco scenario will operate similarly to Ralf's documented select-accy scenario: the second example in his 2.2- Communication with the NCE ProCab section, where each keycode is sent in separate 2-byte responses to successive pings.  Note: Ralf says:

  • Lines in bold are communication from the cab to the command station.

  • Each byte is shown in hexadecimal without the 0x prefix followed by the corresponding ASCII letter when relevant.

  • I omit the “pings”, which precede each command station message.

Edited by aardvark
Link to post
Share on other sites

  • 6 months later...

Slightly off topic (but hey, it's my thread) ...

 

My fledgling layout is on 4 portable baseboards for the purposes of domestic harmony.  I'm thinking it would be good to have an NCE PCP panel at each end, plus one of the workbench/programming track.  This would mean that I need to buy two more, but at A$60 a piece, I am giving this some thought.

 

I'm not expecting to need more than the PowerCab, so the CAB-bus connectors will go unused. DCC Concepts have a replacement at £19, which is cheaper but still expensive for the functionality I actually need: DC power into the PowerCab, and DCC out.

 

It occurs to me that all I need is a panel-mount RJ12 6P6C, which can be had for under A$8.  The PCP also has an LED and resistor so you can see when you have DCC power, and a Transient Voltage Suppressor Diode (TVS diode or TVSD), which ensures that your DCC command station doesn't cause an over-voltage on the DCC supply and fry your precious decoders.  Seems like a good idea. I think the one on the PCP is rated at 1.5KW, 18V.

 

 

Link to post
Share on other sites

On 31/07/2021 at 00:23, DonSn35Quixote said:

Another response from NCE support was not quite so helpful. In response to a question of how to calculate the CheckSum, this:

 

"The first 4 bytes are Xor'd together and will result in the 5th byte."

 

Documentation says add the first 4 bytes and Xor them.  But Xor require two bytes.  I get the sum byte, but Xor'd with what other number?  I suspect FF, but not sure. Ralf's Train Pages gives examples, but I cannot get his checksum values from his data no matter how I do the Xor.  

Not sure this is what NCE are doing but a common algorithm:

 

XOR the first bite with second store result as A

XOR A with the third byte store the result as B

XOR B with the fourth byte - this is your checksum, store it in fifth byte

 

Worth a try

 

Cheers

Dave

 

  • Thanks 1
Link to post
Share on other sites

  • RMweb Premium

If you're not planning to use anything other than the PowerCab you will need to remember that you'll lose dcc power whilst the PowerCab is unplugged.

 

Have you thought of putting the PCP somewhere near the middle of the layout and using an extension (6-way) lead?

  • Interesting/Thought-provoking 1
Link to post
Share on other sites

The PowerCab generates the DCC, so I did know that, but if you meant that everything would halt abruptly when I unplug it to move the PowerCab from one end to the other, then no, I hadn't thought about that. :nea_mini:  So thanks.  Your suggestion has merit. DCCConcepts at one time had a coiled cable for this purpose, but it appears to have been removed from their website.

 

However, I couldn't play operate the half of the layout that didn't have the PCP. Currently, I scramble underneath to hookup the PCP, which dangles on cables. This is a flexible albeit short-term solution.

 

Further thought is required.

 

Or maybe I should just open my wallet :scared:

Link to post
Share on other sites

2 hours ago, aardvark said:

The PowerCab generates the DCC, so I did know that, but if you meant that everything would halt abruptly when I unplug it to move the PowerCab from one end to the other, then no, I hadn't thought about that. :nea_mini:  So thanks.  Your suggestion has merit. DCCConcepts at one time had a coiled cable for this purpose, but it appears to have been removed from their website.

 

 

The problem with a long cable is that the PowerCab generates the DCC.  So, all the DCC signal goes down the spindly thin wires in the long cable, with all the resistance losses of a long length of spindly thin wire.    This causes problems.  

 

However, if you were to have two handsets, then one of them is the "Central PowerCab" (generating the DCC), and the other one becomes a secondary "PowerPro" connected to the CabBus network - ie. a dumb handset which is only sending data signals over the wires, which can then be long without significant problems.  

 

 

- Nigel

  • Agree 1
Link to post
Share on other sites

  • RMweb Gold
1 minute ago, Nigelcliffe said:

 

The problem with a long cable is that the PowerCab generates the DCC.  So, all the DCC signal goes down the spindly thin wires in the long cable, with all the resistance losses of a long length of spindly thin wire.    This causes problems.  

 

However, if you were to have two handsets, then one of them is the "Central PowerCab" (generating the DCC), and the other one becomes a secondary "PowerPro" connected to the CabBus network - ie. a dumb handset which is only sending data signals over the wires, which can then be long without significant problems.  

 

 

- Nigel

 

Beat me to it Nigel, a Pwerpro handset is an excellent investment :)

  • Like 1
Link to post
Share on other sites

On 16/02/2022 at 09:09, Nigelcliffe said:


…….and the other one becomes a secondary "PowerPro" connected to the CabBus network ……

 

On 16/02/2022 at 09:13, RedgateModels said:

….. a Pwerpro handset is an excellent investment :)


Just for clarification ( and a bit of gratuitous pedantry), the correct name for the additional handset ( throttle) is ProCab.

 

PowerPro is the name for the complete, full, NCE system.


 

.

  • Like 1
  • Agree 2
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...