I'm working to consist 2 P2K E7A's (back to back) and this is my initial venture into consisting. I'm using a MRC Prodigy Wireless and have chosen, for reasons not specifically related to my question, to go with Old Style/Universal consisting on this initial attempt. The lead unit is a fresh from the box QSI equipped version and the trailing unit is a very early Life Like version with either a 1st generation MRC or Lenz decoder c1996.
It is working OK, but when consisted electronically but placed a foot apart the older, trailing unit catches up with the lead unit fairly quickly. Do I need to set SV, ACC, DCC, and TV values exactly the same for both units before going any farther? If so, can you guys suggest values for those entries? If that is not material, then any thoughts? When coupled, they seem to run OK together.
Mike
Not 'exactly the same' as far as values int eh CVs go, but you need to adjust one or both locos so that they run somewhat the same speed across the throttle range. Exactly perfect for muyltiple loops of the layotu is not required, they just have to be reasonably close. That loco with the odler decoder probbaly does nto have BEMF, and probably does nto support CV6 for mid spee,d so you might have to use a 28 step speed curve to match them up
On step 1 or 2, start with CV2 = o on both. Add to CV2 on the slower one to make it run as fast as the faster one. The QSi will probably creep in step 1, the other loco might not even move until step 10 or more, in which case set CV2 so that it moves as slow as it can reliably go on step 1 or 2, then adjust the other loco to be the same speed.
Same thing at full throttle, only this time it's CV5. Here you want to adjust CV5 to slow down the faster one, with CV5=0, the speed at full throttle is as fast as the loco will go, you can't make it faster, but you cna sue CV5 to slow down the ones that runs faster.
This might be enough, but try mid throttle and see. The QSI will support CV6 for the mid dpeed and you can asjust that up or down to try to match the other loco.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy, here is what I've discovered so far and am not sure what the next step is. QSI moves at step 1 (28 speed step) and OD (old decoder) doesn't budge until step 5. At step 5 QSI is still moving slower than OD which is moving on out. At step 8 QSI is about the same as OD at step 6.
CV2 setting on QSI is 14 and CV5 is 1. I can't get a reading on CV6. OD is not letting me read CVs, although it has in the past sort of hit and miss.
I think I need a step by step process to at least get them to the same speed at different speed steps and then guidance on which CV to program. I'm a bit confused.
You're goign to ahve a touch time consisting an old limited decoder like that, you might actually need to upgrade it to somethign with a few more features that will run better with the QSI. Atleast to get overall satisfactory operation.
At ther very least, you will need to keep adding to CV2 ont he OD to get it to move before step 5. And then since the QSI is still runnign slower at step 5 then the OD is moving, you'll have to increase CV2 on the QSI, which is goign to make it leap into action rather than start smoothly liek it is capable of. This is where a better decoder replacing the old one would help, you could get both locos to start slowly and smoothly.
Once you have them starting, then you cna move on to faster speeds and work on CV5 to make them run the same speed at full throttle. Likely you willhave to slow down the OD so it doesn;t run circles around the QSI at warp speed.
I think I'll play around with the settings before replacing it. At least I'll be learning in the process. Since I don't know the CV5 setting of the OD and the QSI is 1, do you have a suggestion where to reset the OD to start with?
I really appreciate your help.
Default is usually 0, which means, apply full voltage to motor.
Most decoders have a range of 0-255, where 0 and 255 really mean the same thing - max. Some use 0-63 though - mostly Loksound.
One thing to watch out for, if CV2 is say 15, don;t set CV5 to less than 15 (unless it's 0). Logically it doesn't make sense - why would you want to loco to go slower with a higher throttle setting? Different decoders handle this differently. Some just act wierd, others ignore the CV5 if it's less than CV2, and treat is as if it were set to 0. Just don;t do this, then there will never be a problem.
On the faster engine, you just have to kinda take a guess and start with that and see how it works. If the old engine is twice as fast as the new one, try setting the CV to half the maximum - around 120. If it's still too fast, drop it to 100...if it's now too slow, try 140. It can be time consuming, but normally you can get it if you stick with it.
BTW when one engine starts quicker than the other, you can sometimes overcome that by using CV3 to delay the start time of the "jackrabbit" engine a little. Sometimes adjusting CV3 in the quicker starting one a little and CV2 in the slower starting one little will end up making them work together well.
I have not had a chance to work on this problem since my last post, but I really appreciate the help. tomorrow is --I hope-- set aside to begin sorting out the problem. I'm still not quite sure what the first step is. I plan to set CV2 for the old decoder (OD) to 14, which is the same as CV2 in the QSI. If the OD is faster, then I'll set it to 7 and try that. If I finally match them closely using that process then I'll go to CV5 on the OD and set to 150 and do the same on the QSI. If this is not the right approach, please let me know.
You should first attempt to identify that old decoder. 1996 era Lenz decoders did not have CV6 mid speed and some did not have CV5 max speed. Lenz preferred to use speed tables to match speed if desired. This is true up to their latest decoder offerings.
Old MRC decoders did not have CV6 mid speed and many models did not have speed tables either. These were the " basic-est " of basic decoders. Many required Register mode programming and could not be read. If yours will take a long address, it may be a little newer.
Martin Myers
Other than the address (0008) which was probably set via an old MRC Command 2000 system, I have not been able to get any read-back fron the decoder. HOWEVER, it just dawned on me that I have a non-functioning (burned-out???) decoder from the other E7--installed at the same time by the same guy-- that I can examine to see if it has any identifying information. Will report back.
Well, I finally got the QSI and the OD matched at the starting voltage. Now I've got to try to match ACC rate (CV3). QSI reads 0 so any suggestions where to reset the OD, or do I need to reset QSI too? At starting voltage, OD accelerates away from QSI withing a few seconds. I don't find any markings on the OD that would indicate mfg, but I'm guessing MRC
I find it works best to get the engines speed matched first, then adjust the momentum CVs. It sounds like one engine is going faster than the other one, you'll need to adjust them so they run together well. Maybe start at full throttle. Take the one that is faster and lower CV 5 a little at a time until they go the same speed. Then try them at half power. If one is faster, use CV6 (if available) to adjust one so they both run the same speed.
CV 3 and 4 determine how quickly the decoder works thru the speed steps to the speed you've set the throttle to. The higher the number, the longer it takes for the engine to get up to the speed you set it at. I usually set the throttle around 1/2 power or less and see if they start together. I usually give all my engines some momentum to start with, then adjust the CVs on one to speed up or delay the time it takes to get up to speed until they both start, run and stop together.
Well, this may be the end of this little drama. Tried to reset the top voltage today on the OD and, to make a long story short, lost address on that decoder. Several attempts to set a new address --several different-- all came to nothing. I'll let it rest for a day or so and then see what I can salvage.
I think it's replace the OD time and quit wasting mine. Thanks for your help. I'll post a final outcome when it happens.
A final question before I replace the decoder. Is there another way to reset to factory defaults-- add 3, etc.-- other than reprogramming CV 8 to 8? I tried that and it did not take. I think the decoder is kaput, and good riddance, but my old hard head keeps telling me to try "one more thing."
Different decoders use different options for reset. CV8=8 is for Digitrax and a few others. Older decoders often did not have a reset option, so you might be out of luck there. Try setting CV29 to 6 and CV1 to 8 and see if it gets back to responding on address 8. If you might have messed up the speed or acceleration, set CV2, 3, 4, 5 and 6 (if it has 6) to 0. That's the default.
Thank you, Randy. Here's what happened. Reset CV29 to 6 and CV1 to 8. IT WORKED! Reset CVs 2,3,4,5, and6 (maybe) to 0. Dead in the water including the CV1 address.
I'm going to reset each of the CVs 2-6 one at a time and see what happens. If this wasn't so maddening, it would actually be a fun problem solving exercise.
Dunno how 2, 3, 4, 5, and 6 can affect 1 and 29, but somehow it is.
One thing to consider is that the older locomotive may never work as well as your newer one, regardless of the decoder. I personally gave up speed matching an old athearn blue box GP60 to my new athearn genesis SD60I because I had to make the Genesis run like an old locomotive so it would work with the GP60. I don't know too much about the performance of you locomotives, these scenarios could be worlds apart. Just something to consider...
Well, I continue to mess around with this old decoder and have concluded that the statement that it will never work as well as the new one is most likely correct, However, I have learned a couple of things that might be of interest to those who are following this thread. First, it seems that trying to change the value of any CV other than 2 has the effect of resetting the address to the value entered in the CV. That may not hold true with every CV, but I don't think I'll play with every one to see what happens.
Second, and most significantly, I've managed to get them kinda close in speed matching. What I did was read CV25 on the QSI (value was 2) to see if there was a factory pre-set speed table curve. I then set the OD CV 25 to 2. That reset the address to 2, but they were much closer in speed even though the OD did accelerate faster after a minute or so.
I'm going to run them for short periods and see what happens.
Thanks for all the hepl so far.
That old decoder may be older than you think and only support register mode programming. This was back from the early days of DCC and very limited in what could be set, and possibly trying to set CVs directly is altering things in a way they are not intended.