Digitrax DH121 in the B unit. LokPilot LPS in the A unit.
They should run same speed and they do in DC mode without decoders.
Using my MRC Tech 6 I’ve fiddled around with CV29 to activate dual mode and neither locomotive responds to DC power. I’ve experienced this before with older decoders and the Tech 6. I think it’s the type of DC power it delivers.
Since the MRC Tech 6 always has DCC mode available it doesn’t really matter practically speaking. I would just use a regular DC powerpack if I were planning on doing a lot of running of DCC locomotives in DC mode with other DC locomotives. It has been my experience that running DCC in DC mode with other DC only locomotives just isn’t pleasing. More so with sound because of the radically different starting voltage, but even motor only DCC decoders run locomotives in DC differently than the same DC locomotive will run without the decoder at all.
MRC claims its Tech 6 can access and reprogram any CV value and that seems to be the case. You enter programming mode by pressing the P button on either the unit or the handheld addon “throttle”. I use the throttle because it has a display. I’m not sure how you would access the CV directly without the handheld unit to display what you’re entering and where. Anyway, after P you select the locomotive number and then you get SV (dont recall what that is just at the moment) followed by “acc” then “dec” then CV. If you enter a CV number the next number you put in and enter will set that CV to the inputted number. Then you get CV again sequentially until you select “enter” without inputting any value for the CV. Selecting “enter” without inputting a number then completes the programming for the decoder in that locomotive. You can run up to 6 addresses but you can have any number of decoders with their own settings at the same address. For example, you can set one #4 locomotive to run in reverse direction (by
The Loksound is going to have better motor-control than the Digitrax decoder so you are going to have to speed up the Loksound to match the Digitrax. I wouldn’t bother with the speed curves. I would only speed match them using CV2 (Vmin) & CV5 (Vmax) and CV6 (Vmid) - i.e. if both decoders support the latter.
Or…you could just purchase an identical Loksound decoder and install that in the B-unit. It should then be easier to speed match the two locomotives given that they have the same brand decoder.
Thanks. I was hoping there an easy way to slow down the Digitrax decoder.
I have the MRR DCC projects volumes 3&4 both of which describe speed matching. I’ll give those ideas a try and then, if nothing like thatvworks, I’ll try my hand at installing a LokPilot LPS.
I’ve already had to resolder two broken solder joints on the lightboard where the decoder installer did a neat job of soldering but the wire fatigue broke right on the pad. My feeling is the installer cut the decoder wires too short and made it unwise to move the decoder up or down after installation. Trouble is the light board can’t be removed without lifting up the decoder to unclip the wiring. The LokPilot installation parks the decoder over the other truck and leaves long wires to fold back over the light board. Much better installation practically speaking. Loksound wire also has very flexible insulation unlike the very stiff wires on the Digitrax.
What you should do first is 1) adjust your Digitrax decoder to as slow as it will go on speed step 001 with CV2 (Vmin) then 2) raise CV2 on your Loksound decoder till it matches the start speed of the Digitrax decoder. Once that’s done adjust CV5 (Vmax) on each decoder to speed match their top speeds and that should be good enough.
For long runs of wiring I like to twist or braid the wiring as I’m installing a decoder. For 2 wires I twist; for 3 or more wires I braid. This really helps tame the wiring and keep it confined and away from moving parts like drive shafts. It also makes it easier to tuck the wiring away or snake it through or around something:
There is. CV3-4 only adjusts momentum - how slowly you get up to top speed or how slowly you slow down to zero. It doesn’t change the speed of the engine at all. CV5 determines top speed.
First, if you’re using speed curves, adjust CV29 so you’re not. Then you can use CV5 and 6 to set the engine’s speed. I would suggest changing CV2-3-4 to zero on both engines so you can get them ‘up to speed’ on your limited trackage more quicky.
If the Digitrax-equipped engine is the faster, make that the lead unit in a consist with the Loksound engine. Then run them as far apart as you can (or on parallel tracks next to each other if possible) at less than 1/2 power. Use CV6 to slow down the Digitrax engine until it’s going the same speed as the other one. Then double the value in CV6 and put that in CV5.
Then, you can adjust CV3-4 for momentum, and CV2 start speed if one starts a lot quicker than the other.
My preference is to slow down the Digitrax decoder rather than speed up the Loksound.
I’m first going to test the relative top speeds on our continuous loop in DC mode.
I’ll test the start up speed setting also.
Our main layout is wired for the Tech 6 to plug in directly in place of one of the DC powerpacks so I’ll take that Tech 6 over and test using both DC with the MRC DC powerpack (to check the DC speeds are similar) and then DCC speeds with the Tech 6.
Neither C Liner responds to the Tech 6 in DC mode.
With any speed matching your “fastest” decoder at speed step 001 will become your “common denominator” and I’m going to guess that that is going to be the Digitrax decoder in your B-unit. If the Digitrax will only slow down so far (after adjusting CV2) then you have no choice but to speed up the Vmin of your Loksound decoder. It’s exactly the same but opposite for Vmax - i.e. with your slowest decoder at top speed becoming your benchmark for the faster decoder.
CV2 is only kind of a “jump start” to get an stagnating engine moving. If one engine starts to crawl at speed step 1 and the other doesn’t move, you can adjust the hesitant one’s CV2 from zero to whatever it takes until it too starts to move at speed step 1.
However, CV2 has nothing to do with how fast the engine goes otherwise, just boosts the power it gets at the start. You need to use CV5 and (if the decoder has it) CV6 to speed match the engines. I’d recommend doing that before worrying about CV2 - or momentum CVs 3 and 4.
The B unit starts moving before the A unit gets going. The B unit appears to accelerate at a higher rate in the lower half of the speed range. I run out of track before I can properly compare the top speeds or even the upper speed ranges.
The B unit clearly runs at higher voltage than the A unit is seeing downstream of the power input to the decoders which of course is at the same speed step for both.
The A unit also seems to run slower when the B unit runs at the same time. Only one power district is available at the moment.
This testing if speed ranges can all be sorted out on our larger layout which will allow me to time the speed differences at different throttle settings. Even in DCC mode I have the two units addressed as #3 (Tech 6 has no formal consist mode). It is a bit tedious to remove one unit from track to recode the other unit and then vice versa. Initially I reset both decoders to their respective factory defaults as a starting position.
Tech 6 assigns address 3 by default unless I’m using the handheld addon unit allowing up to 6 addresses to be assigned. My habit is to test run any newly acquired locomotive as address 3 until I’m happy with it. Then I assign a different number and recode any changes needed such as one unit running in reverse mode for two diesels normally MU’d back to back. Those two get addressed as one number but the coding differs.
Not too long from now I plan on acquiring a DCC “system” and related software to allow messing around with all this on a screen and a programming track but for now I’m just discovering how this DCC seems to work. Tech 6 is very simple and seems pretty foolproof but it can be hard to be sure you know what it’s doing,
Yes, I figured that one out. If I have to match speeds anyway I’d rather not bother also removing the Digitrax and fitting a new LokPilot LPS. Current LPS readily available around here do not have wires. So far as I’ve looked anyway.
Sure but the decoders made by ESU are commonly described as Loksound decoders, even the motor only versions. LokPilot is the trade name used by ESU for motor only decoders.
The decoder itself is labelled with LPS on the circuit board, as I originally posted.
Apparently the S stands for Standard in that acronym.
Keep in mind even if you put identical decoders into identical locomotives, making all the settings may not make the two engines run the same. If you make CV5 200 for both, it’s still quite likely one will run a little faster than the other.
Basically all decoders use CVs 2-3-4-5 to control speed and momentum (and in recent years they all include CV6 for midrange), so can be adjusted to make the engines run the same in a consist even if the decoders are from different manufacturers. The difficulty comes in if you have put in a speed curve, which can make it much harder to speed match two engines.
