ID's allocated to Accessory Decoders

[37lover]

Is there any way I can simply and quickly check to see what ID's are allocated to the Accessory decoders installed on my layout? I do not have Railmaster Pro.

I do have a Sir Tom Moore Class 66 and was hoping to allocate the number 66 to this loco but at the back of my mind think the range of numbers around the 60's may have been used for the three AD's on my layout. I don't want to use long addresses. I am of course assuming that I can't use the same number for a loco if already allocated to an AD.

[Chrissaf]

In DCC the packet format for an 'Accessory Packet' is constructed differently from a 'Locomotive Packet'. The NMRA DCC Standard provides the ability for Accessory addresses to operate in the range 0001 to 2,048 and Locomotive addresses to operate in the range 0001 to 9,999. Thus there is a 2,048 address overlap where an address can either be an accessory or a locomotive. There is a part of the DCC packet that defines whether that address should operate an accessory or operate a locomotive. Therefore an Accessory will ignore Locomotive packets and a Locomotive will ignore Accessory packets, even though those two packet types might have the same target DCC Address in them.

The short answer is therefore you can safely have an accessory with address 66 as well as a locomotive with address 66, there is no conflict.

You mention RailMaster and this question is in the RM forum, so this should not be relevant, but if you were using a Hornby Select DCC controller then that controller does not allow the same address to be used for both Accessories and Locomotives.

[37lover]

Chrissaf,

Many thanks for the "short" answer, I understand that bit grinning. I do have a Select but if I am not using RM (that is, it is not powered up) I use my Elite but only for running locos round for a few circuits on track cleaning duties.

[96RAF]

In that case 37L enter Design Mode in RM and click on each point on your track plan. The pop up box will indicate which controller is being used (A or B) and the accessory address in use.

Following on from what Chris said about loco and accessory addresses being sent differently you will have noticed on the Elite there are Loco and Acc buttons used when selecting an address and this is where Hornby applies the correct binary coding for the DCC signal. If you want to see what this coding is in detail the NMRA publish the protocol on their site in the DCC section.