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ESU Decoders & NCE Advanced Consisting

Posted by on Mar 6, 2017 in Tips DCC Components |

Dave Heap on the NCE Yahoo Group has been conducting some tests and unfortunately it has become evident that ESU decoders are not 100% compatible with all the NCE Advanced Consist commands. Keep in mind, the fix is relatively simple, but NCE owners who use ESU should be aware of the potential issue.

The area of non-compatibility is the CLEAR ALL ADVANCED CONSISTS command. This command sends an NMRA Standard consist control command to the broadcast address:
Instruction Packet: L000 CON=000F
DCC Packet Hex: 00 12 00 12
V4 and V3.5 decoders ignore this command.

On the other hand, the CONSIST DEL <loco address> command does work with ESU decoders, as do the SETUP, CLEAR, ADD and DEL commands as these send NMRA Standard consist control commands to a specific loco (or consist) addresses.

For example CONSIST DEL 4303 ENTER:
Instruction Packet: L4303 CON=000F
DCC Packet Hex: D0 CF 12 00 0D
ESU decoders respond fine to this command.

I tried a few other broadcast commands:

Program on Main CV19=0 to the broadcast address:
Instruction Packet: L000 CV0019=000
DCC Packet Hex: 00 EC 12 00 FE
ESU decoders ignore this command.

Function commands (e.g. Lights, Horn) to the broadcast address:
Instruction Packet: L000 F—2-
DCC Packet Hex: 00 82 82
Instruction Packet: L000 FL—-
DCC Packet Hex: 00 90 90
Instruction Packet: L000 F—–
DCC Packet Hex: 00 80 80
ESU decoders respond fine these commands.

I didn’t try speed and direction commands because I didn’t want every loco on my layout moving (having all horns/whistles sounding at once is loud but harmless).

From NMRA S9.2.1 section B:
B: Broadcast Command for Multi Function Digital Decoders
The format for this packet is:
{preamble} 0 00000000 0 {instruction-bytes} 0 EEEEEEEE 1
Instructions addressed to “broadcast address” 00000000 must be executed by all Multi Function Digital Decoders.
The single instruction has the same definition as defined by the Multi Function Digital Decoder packet and can be one, two, or three bytes in length depending on the instruction. Digital Decoders should ignore any instruction they do not support. The manufacturer must document which broadcast commands a decoder supports.

The wording of this section is (again) ambiguous:
– It could be interpreted that all decoders must support broadcast mode for all commands they support.
– It could be interpreted that decoders may choose which broadcast mode commands they support, but that this must be documented.

have been conducting some tests and unfortunately it has become evident that ESU decoders are not 100% compatible with all the NCE Advanced Consist commands.

The area of non-compatibility is the CLEAR ALL ADVANCED CONSISTS command. This command sends an NMRA Standard consist control command to the broadcast address:
Instruction Packet: L000 CON=000F
DCC Packet Hex: 00 12 00 12
V4 and V3.5 decoders ignore this command.

On the other hand, the CONSIST DEL <loco address> command does work with ESU decoders, as do the SETUP, CLEAR, ADD and DEL commands as these send NMRA Standard consist control commands to a specific loco (or consist) addresses.

For example CONSIST DEL 4303 ENTER:
Instruction Packet: L4303 CON=000F
DCC Packet Hex: D0 CF 12 00 0D
ESU decoders respond fine to this command.

I tried a few other broadcast commands:

Program on Main CV19=0 to the broadcast address:
Instruction Packet: L000 CV0019=000
DCC Packet Hex: 00 EC 12 00 FE
ESU decoders ignore this command.

Function commands (e.g. Lights, Horn) to the broadcast address:
Instruction Packet: L000 F—2-
DCC Packet Hex: 00 82 82
Instruction Packet: L000 FL—-
DCC Packet Hex: 00 90 90
Instruction Packet: L000 F—–
DCC Packet Hex: 00 80 80
ESU decoders respond fine these commands.

I didn’t try speed and direction commands because I didn’t want every loco on my layout moving (having all horns/whistles sounding at once is loud but harmless).

From NMRA S9.2.1 section B:
B: Broadcast Command for Multi Function Digital Decoders
The format for this packet is:
{preamble} 0 00000000 0 {instruction-bytes} 0 EEEEEEEE 1
Instructions addressed to “broadcast address” 00000000 must be executed by all Multi Function Digital Decoders.
The single instruction has the same definition as defined by the Multi Function Digital Decoder packet and can be one, two, or three bytes in length depending on the instruction. Digital Decoders should ignore any instruction they do not support. The manufacturer must document which broadcast commands a decoder supports.

The wording of this section is (again) ambiguous:
– It could be interpreted that all decoders must support broadcast mode for all commands they support.
– It could be interpreted that decoders may choose which broadcast mode commands they support, but that this must be documented.

For the technically inclined, the DCC instruction packets for:
– Consist Control have 0001 in the first four bits of the first instruction byte.
– Program on Main have 111 in the first three bits of the first instruction byte.