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Post by ztrack on Oct 31, 2017 20:13:56 GMT -5
So how easy is it to install a Digitrax decoder in an AZL loco? See for yourself!
Rob
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Post by neverland on Oct 31, 2017 20:30:40 GMT -5
Now I have to wait for my loco release date!
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Post by modelwarships on Mar 10, 2020 10:42:45 GMT -5
I did 3 GP30's last night. I like these as you can reach the motor tabs to check continuity with the decoder motor contacts ensuring you are making good contact before putting them back on the tracks. I have noticed that many of the newer AZL loco's have filled this area in making it impossible to check. This makes adding decoders a trial and error process.
It would be nice to see other AZL models included with documented instructions for assembly and disassembly.
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blid
New Member
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Post by blid on Oct 10, 2020 8:06:17 GMT -5
I have just received two GP30s with Digitrax DZ123Z0 decoders. The track voltage measured with a true DCC RRampMeter at the tracks is 11V (measured with a load as suggested). This is the max voltage recommended for my Freudenreich engines and they run just fine. The GP30s are very slow. The max speed is like 40 scale miles per hour.
What voltage are you using for the DZ123Z0 and AZL motors? What is the recommended max?
blid
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Post by markm on Oct 10, 2020 9:43:46 GMT -5
The GP30 are 12V motors as is most of the AZL line. The "Official" maximum voltage for Z is 10V. I find all the AZL GPs consistently run a prototypical 70MPH at 9V with no load.
When it comes to DCC, whether a new board or previous owned, I find the best practice is to do a master reset: CV08 set to 8.
You really don't know what state the decoder was in when it left the factory nor what speed tables and upper limit a previous owner may have set. If you browse the forum you find it's amazing how many problems are fixed that way.
Mark
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blid
New Member
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Post by blid on Oct 10, 2020 13:33:21 GMT -5
The engines and decoders are new. I have been in touch with Digitrax and reset has been performed. So far no cars on the hooks. Can't understand why they are so slow when DCC. I have also tested in analog with a Marklin 67011 transformer. Then the speed was OK. The transformer is nominal 10V but I measured 13V at the tracks under load at full throttle.
A warning. Don't reset a decoder unless you know that the default values are suitable for the motor or you know what CV-values to set.
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Post by markm on Oct 10, 2020 14:24:09 GMT -5
First, 13V is not unusual for the Marklin throttles. Marklin locomotives typically run 5-10 times the current of the AZL units and the regulator frequently does kick in at the lower currents.
New question: how do the locomotives perform immediately after the CV08 = 8 reset? Are you programming any other CVs and what values?
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blid
New Member
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Post by blid on Oct 10, 2020 14:50:19 GMT -5
This is after CV8 reset. I have tried with 102 in CV57 as suggested by Digitrax. I didn't notice any difference. It is now back to 6. I intend to set the switching speed and CV4, CV5 and CV6 tomorrow. I tried it before reset but it just made them go slower or no change whatever I did. It is as if the decoder limits the voltage to the motor when DCC. I know that there is a loss of voltage in any decoder but here it seems to be to much (the 11V recommendation is because the output to the motors in the Freudenreich will be 10V).
I will try to set the analog to 11V and check the speed. |
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Post by markm on Oct 10, 2020 16:08:27 GMT -5
It's always hard to diagnose from a distance but I can make some suggestions. First set CV57 = 0. Back EMF does funny things with Z because the current flow is too low. Set CV2=2 CV6=128 CV5=154. CV2 is starting speed, CV6 mid-range and CV5 top speed. I suspect if you set these you'll get better results.
CV4 sets the deceleration rate which for the time being set to 0.
I'd suggest you download a copy of Digitrax's decoder manual. It will explain the function of all their CVs. If you decide to use TCS decoders, download their comprehensive decoder manual. Likewise for any other decoder manufacturer you may select. Only a small number of CVs are standardized, the rest are the manufacturers' choosing.
Don't let this get to you, I've struggled with the CV. The really important one to program are CV29 the control register CV01 or CV16 & CV17 the locomotive address, CV2,CV6,CV5 the 3-point speed curve. Factory setting work for about everything else.
Hope this helps,
Mark
I should add that after the reset the locomotive should run at short address 02 with no further programming. It will use a built-in linear speed table.
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blid
New Member
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Post by blid on Oct 11, 2020 8:27:37 GMT -5
Thank you for all the help. Things are improving but first let me correct a couple of typing errors. The long address is stored in CV17 and CV18 and the default address after reset is 3. After I lowered the analog voltage to 11V the speed was still decent. I clocked it to 64 smph. Zero to CV57 made no visible difference. I changed it back to 6. Will probably make a difference with a string of car. Setting the 3 point speed table increased the speed with CV5 =255 giving a speed of about 50 smph. I bit low but I intend to haul a long string of cars and if it can keep this speed I can live with it. I checked in reverse. Then the speed was about 70 smph. Not 83 but good enough for me. I don't run the trains at the engines prototypical max speed anyway. One of the engines/decoders didn't like the acceleration time in CV3. It stuttered and wouldn't start. I have not messed with the switching speed. With the noticeable difference in speed between forward and backwards maybe it it a matter of braking the engines in. I guess these engines don't have more than say half an hour running time. Do you let your engines run for an hour or two just to break them in?
blid
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Post by markm on Oct 11, 2020 9:16:34 GMT -5
Yes, it's always a good idea to do a burn-in run. I use 15 minutes each forward and reverse half and full throttle. Sometimes it makes a difference, sometimes it doesn't but since I pull all my locomotives through an incoming inspection, I like to start at a known point.
It seems to me that your speeds are pretty much in the prototype ball park of 65MPH max.
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Post by tjdreams on Oct 11, 2020 13:53:29 GMT -5
I agree with Mark I always run my Locos for a hour or two to brake them in before adding a decoder. I also recommend using a figure 8 track for braking in, That or run it forward in a clockwise loop then physically pick it up turn it around and run it forward in a counter clockwise loop. Then do the same for reverse direction so its broken in equally forward and reverse traveling in both clockwise and counter clockwise radiuses.
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Post by BAZman on Oct 12, 2020 23:35:37 GMT -5
Couple of guesses.
What DCC System are you using?
Are you running the loco on the Programming Track? That certainly won't run a loco.
CV8 default can only be done on the Programming track (not on the Main [e.g. the normal DCC power on the running track] )
If defaulted CV8, then the 'Speed CV's 2, 6 & 5 (Start, Mid & Max). They will read 0 or 255 depending on the DCC system but will actually run to the highest (full) value. You could program CV5 to 255 and CV6 to 128 (don't need to program CV2 as it will already be at 0. Something is wrong with yours.
Also, CV3 (Acceleration) and CV4 (Deceleration) *plus* the CV's for BEMF, etc. *** This*** is BAD on Digitrax as EACH time you reach a dead spot, the "Speed" restarts from Speed 1 !!!! This causes a slow crawl from 0. Set CV3 & CV4 to 0 to stop this and make the loco react instantly to your Throttle/Controller.
The track voltage is fine !!! And, the CV's do NOT change the actual Voltage to the motor. The motor runs on PWM (pulses) that *always* the entire DCC supply voltage (minus o.5 Volts). If you read the motor voltage, it will appear to to change from 0 to ~12 volts. But on an oscilloscope, the waveform will changed from very short pulse to nearly 100% 'on'. You could try probing the two motor contacts while you have a stall pin in front of the loco. At Speed Step 128 (or what ever max value your Throttle displays and you should see ~12 volts (not say 8.2 or such)
The BEMF CV's generally will help a poor motor, especially starting. Yeah, the sensitivity is not so good but it works but I don't use it as I consist locos and it is well know that the there is a lot of unwanted interaction. And if the loco runs correctly on DC, it will run better, no matter what, with DCC - especially at low speeds.
Depending on the DCC system, you may be in Yard mode which makes locos run 1/2 speed (in general)
Can you swap the decoder with another working loco?
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blid
New Member
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Post by blid on Oct 14, 2020 6:46:22 GMT -5
I now have the answer to the poor behavior. As a side note in a Swedish forum, about something that I don't have, it was mentioned that Digitrax decoders don't like Railcom. My controller was set to use Railcom. That is now turned off and the problems seems to be gone. Thanks again for all your input. I am new to Z-scale digital and have a lot to learn.
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Post by markm on Oct 14, 2020 7:29:54 GMT -5
Congratulations on getting the locomotives working the way you want them. Your solution is something I would not have thought of. Many of us have learned something new along with you.
DCC looks so simple, and most of the time it is. But some "tricks" for it's use would be worthy of a university course!
Mark
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