CV Number changes on older ESU lok sounds decoders?

andyspencer

andyspencer

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Evening guys. I've finally get my DCC set up sorted - Running an MTS3 with a massoth nav and wireless device.
I've been playing around trying to alter basic CV's on an older generation ESU chip. But the instructions I'm using are for a v3.5. Should these be the same cv's? All I seem to have done is made the max speed really low and lost the headlights function... Trying to put them back to a sensible setting doesn't seem to make a difference...
What am I doing wrong?
 
Did you keep a record of exactly which CVs you altered and to what values? Post them here?
There are only a few standard CV numbers that all decoders should treat as the same. Within the same brand of decoder more of the same CVs tend to get used for the same function.

I could make a couple of guesses (but that's all they are):
If you've changed something like CV5 or CV6 (vMax, vMid) this could affect the maximum speed, so set CV5 to 255, CV6 to 128 and see if this helps?
If you've changed the speed steep setting (part of CV29) this can affect how headlights behave if you've now got the speed steps of the decoder different to the speed steps your DCC system is sending out.

To reset an ESU decoder, write value 8 to CV 8. I think this holds true for all ESU decoders that I've ever come across.

Of course this is a bit after the event, but this is precisely where using something like a SPROG and JMRI software would have helped as you could have read and saved all the original CV values before fiddling, and then load them all back again if something screws up!
 
Thanks guys. I was looking at getting an ESU Lokprog, but couldnt wait... As I'm using a Massoth nav, I've no idea what the start settings were. Since my first paniced message I've rechecked ESu website and found some V2 instructions. There are some differences, and i've now sorted headlights and speed.
Next question is in regard to a cv number that has a number of different bits...how does altering these work? I've only altered so far something that just needs a single number such as max speed etc.
New to all this but should be able to pick it up quickly enough.
 
Where a CV stores bits rather than a single value, then typically each bit acts as an on/off switch for a particular feature. But you can only write whole bytes to a CV (8 bits) so you have to calculate the value by adding together the "powers of 2" for each bit you want to turn on.
It can be trucky to explain in writing, and different decoder manufacturers use different names or arrangements for the bits in a byte. Usually there's a helpful table somewhere in the manual!
As I'm a programmer/software developer by trade, I tend to think of it like this:
bit 0 = 1
bit 1 = 2
bit 2 = 4
bit 3 = 8
bit 4 = 16
bit 5 = 32
bit 6 = 64
bit 7 = 128
So... if I want to turn on bits 1, 3 & 5 I need to add together the values: 2 + 8 + 32 = 42. (life, the universe and everything!) Hopefully you can see that if you wanted all the bits turned on you'd add up all those numbers and get to 255 = the maximum value a byte can hold.
Depending on the decoder manufacturer, they might name them bit 1 to bit 8, and even swap the whole lot round so that bit 8 = 1, bit 1 = 128 etc. All great fun!

Again this is A LOT easier with a software decoder programmer such as JMRI and a SPROG, which hides all this bits and bytes complexity and just gives you tick boxes to choose what features you want turned on.
 
I have tried with a 3.5 decoder and just about got it right .:wits::wits:
the cv's also control other functions as well as the prime number So you might have a light on going forward and a sound going in reverse with a flashing light.
I keep saying I'm going to get a sprog but as of yet, well for one loco is it worth it ?
Or should I just re chip it with massoth
Not a particular fan of ESU
 
Philbahn said:
I keep saying I'm going to get a sprog but as of yet, well for one loco is it worth it ?
Click to expand...
Only you can judge that of course, but I'd say if you have any interest in fiddling with CVs and also storing settings in case of problems then some sort of software and programmer is a must, whether it be SPROG/JMRI combination, or the LGB/Massoth programming gear or some other equivalent. It never stops at just one loco does it? :bigsmile:
Or should I just re chip it with massoth
Not a particular fan of ESU
Click to expand...
Better not let this thread drift too far from the original question, but out of interest what don't you like about ESU? I don't have any LokSounds but I do have a small bunch of LokPilots in some locos and I find them really nice smooth decoders (some needed to be reconfigured with BEMF settings more appropriate to large scale locos as they came loaded with settings for small scale motors). Got a couple of Massoths and they seem good decoders too. I'd happily use whichever is readily available at a decent price.
 
I use the massoth programmer to read the cv's Nick. Massoth are easy to do all my other locos are LGB or Massoth
It is my Mikado with ESU
 
Just been on the massoth site and see that they have put the French sound on it so I think I might have a spare ESU chip shortly
 
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