# New Airwire G2 decoder,first operating observations



## Paul Burch (Jan 2, 2008)

Just installed my first Airwire G2 decoder. I installed it in an existing loco that already had one of the AW9D10SS decoders so I could get a good comparison. Just a straight swap. There were/are a couple new features that I wanted to test. First is the headlights. The new receiver uses CV60 to set headlamp mode as in I guess other DCC systems. This was not available in the old decoders. I have one of the new NCE Gwire controllers and one of the things that I noticed was that the auto reverse on the headlights didn't work with the old Airwire decoders. There is some info on this in another post on the NCE Gwire. Guess what,the lights now work just fine with the new decoder. I suspect it is just because this new decoder now uses DCC protocol for the lights.
Another feature is cruise control or some form of BEMF. There are two modes that can be used. Auto and manual. I did a test in the auto mode. I set up a train with fifteen cars,mostly fifty footers. On level track the speed was set fairly slow and the cruise turned on using the F6 key per instructions. I then switched the train onto 135' of 2% grade. I noticed absolutely no decrease in speed. It just kept running at the same smooth speed.
Ther are a couple other new features that I will play with in time,motor bump using CV's 56 and 57,and function mapping for a couple on/off outputs using CV's 61 and 62.
The basic setup is still the same as the old decoders.
So far so good.


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## Greg Elmassian (Jan 3, 2008)

Thanks Paul. 

What is the specification for the output current (and does it specify at what voltage). 

How do you like the hardware design, etc.? 

Regards, Greg


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## Paul Burch (Jan 2, 2008)

Gregg, 
The output for DCC iis 3 amps. The two aux. outputs are 1 amp. I'll have to look in the manual to see what reference voltage they were using. This board can be used with a single battery ranging from 12 volts to 28 volts. The board is similiar to the old. It is about 1/8" wider,same lenght. The terminal locations have changed so a little care must be taken before attaching leads.


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## K27_463 (Jan 2, 2008)

Motor drivers are 8 amps a t 15v @ 25C. Output derates 1 amp for every 10 degrees above 25C. On board buzzer for overload and auto reset is a nice feature. The board will let you know if it is too hot...There is also a nice green on board led to indicate the presence of power in the correct polarity. Makes for easy troubleshooting. 

Jonathan/EMW


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## Greg Elmassian (Jan 3, 2008)

Thanks Paul and Jonathan, I was especially interested in the motor driver output... very detailed spec.. and looks "honest"... too many "10 amp" units out there running at 21 volts and not rated 10 amps and 21 volts... probably half that. 

Certainly sounds like significant improvements here.. 

Regards, Greg


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## Paul Burch (Jan 2, 2008)

This new decoder has a new much higher 24Khz frequency for the pulse drive. There is a very noticeable motor hum/buzz in the existing decoders. I turned off the sound and gave it a little throttle. Absolutely no buzz,it is gone. The only thing I heard was a little gear noise.


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## paintjockey (Jan 3, 2008)

Thanks for the info. I have a few locos that i wanna change out to the new boards, mostly for the "cruise control". 
Terry


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## Stan Cedarleaf (Jan 2, 2008)

All the above, Paul. We've found that the F6 "Cruise Control" function is a very, very nice feature.

The G2 is an excellent upgrade to the CVP DCC product line.


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## Madstang (Jan 4, 2008)

So are they wired the same way as the old ones....I use the old ones with the motor outs connecting to the track pickups in the loco's inherant board, then MU the 2 GPs' I use together...Al and the instructions state they you shouldn't do that....what does everyone else do..is anyone else running their mu'ed locos that way, without any problems..I can't see placing a board in both locos and anyway by doing this can you connect 4 motors as it is stated with 2 motors?

Any help would be appreciated before I get my 1st one, and then produce "magic smoke"!

The way I wired them before with the old board was still reccommended not to do it that way, but have NEVER had an issue folowing the instruction sheet that was made and circulated when the old board came out. 

Bubba


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## fsfazekas (Feb 19, 2008)

Madstang, 

I'd assume that the reason you are told that is because by applying power to the rails "backwards" through the power pick ups (are they then called "power put downs"?) you risk issues similar to traditional track power like short circuits/polarity issues. If you adsded track and created a reverse loop or someone left a screwdriver on your rails I can see that would be a "bad thing". If you ever travel to another RR and try to run you could get a real nasty surprise. I there's no issue with running multiple engines from the same board (up to its rated power) but I would strongly suggest that you disconnect the power pickups and connect your units by some type of plug/jumper as in those provided on Aristo-craft engines. 

Not intending to be critical, just don't want to see you burn up any equipment when the risk can be eliminated easily...


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## terry_n_85318 (Jan 3, 2008)

Madstang-- 

Why dou you have track pickups when you are using R/C? You have the possibility of shorting the decoder. 

Best bet would be to remove all track pickups from the engine. Then connect the wires going to the track pickup to the decoder. If you want to mu units, isolate the track pickups on the other engine(s). 

Terry


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## Madstang (Jan 4, 2008)

I think I must have not stated myself correctly.

I feed the battery power from the Airwire board's motor outs, to one of the pickups in the engines inherant board with a mu plug, but also dissconnecting the other pickup on the board....in doing so isolating the track pickups comming from the trucks, and no power is ever getting up to the engines board from the track.

Bubba


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## fsfazekas (Feb 19, 2008)

I must have not understood correctly. I was thinking that the engine with airwire was putting power TO the rails (out the power pickups) so the MU'ed engine trailing it could pick up power from the rails without any modifications. Sorry about that  

Now that I understand what you are doing I do not see why there would be any objection..it seems less work and leaves the engine "more stock" so you could undo your changes if you ever wanted to sell the engine.


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## Greg Elmassian (Jan 3, 2008)

I just had a long and pleasant phone call with Al at CVP. 

There's nothing different in the new decoder that changes the reasoning about connecting the AirWire decoder directly to the motors. They used to recommend that you do not connect the motor outputs to the "track pickup input" of a locomotive, i.e. to the "motherboard". With the new features in the new decoder, they have worded this more strongly, saying "do not do it". 

The additional lighting features in the new decoder are "lost" when you run the entire unit from the motor leads. Instead of constant intensity lighting and all the new features, your lights run like from DC on the rails. 

That's one reason. 

The big reason is that there can be electronics on the "mother board" of your loco that can be damaged and or create damage. 

An example is any voltage regulators on the "mother board".... especially if they are little integrated circuits like on the SD70 MAC, and virtually all Aristo locos. The PWM power that is only intended for the motors is now fed to the smoke unit and these voltage regulators, and this can cause bad things, Al actually measured spikes of 70 volts from one of these regulators in the SD70 when the PWM power was applied to the "mother board" 

So, that's the reasoning. This is "standard" recommendations for ANY DCC install. 

Al did say that Bubba's situation might be ok, since he has been using the AirWire with no problems, but recommends he keep the voltage to no more than 18v on the input. 

Al and I both strongly advise doing a "proper installation" where the lights are connected to the decoder, and the motor outputs are connected to ONLY the motors. 

So, that's the information straight from CVP. 

Regards, Greg


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## Madstang (Jan 4, 2008)

Ok, I heard the same thing, my question also is why would you make aboard that cannot be hooked up to 2 mu locs"???


So lets say I hook it up like the book says, so how do you wire 2 GP-9s'...if you place a board in EACH loco, which is not cost effective, by the books way you would have to have a battery power fee to BOTH engines, that EACH have 2 motors in each of them... as per the instructions??? Cause they do not reccommend connecting to the mother board.

Does that make any sense..my question still stands how would you mu 2 GP-9 together following the logic of the Airwire booklet...by the book you couldnd'nt run 2 locos that have 2 motors in EACH of the locos......

OK maybe if you ran a pass through one of the engines to the other engine to the motors....see my point..all the EXTRA work involved to get this accomplished..is it really worth it..just to control lights and 2 functions when most only trip the whistle and horn...maybe the hiss?!!

Oh yea I recieved the same info from Al, so what I needed was information on someone who has wired the NEW G-2 lke the OLD way, and if they had any problems. 

The old one was also reccommended NOT to hook it up the way most of us have been hooking it up, NOT guitting the electronics and I had no problems at all wiring it that way.

I never run smoke so I am going to dissconnect it maybe preventing the potential spikes. 


So my question still stands.......has ANYBODY wired the G-2 the old way? isolating the track pickups and connecting to one of the mu plugs on the motherboard that was used for track pick ups? If so have you had any problems????


Oh yea and be sure to wire the 6 amp diode on the old diagram cause if you cross the battery + - you will do damageto it like the old boar...no power getting to the engine..or worse...I also got that info from Al.
Thanks Greg

Bubba


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## Greg Elmassian (Jan 3, 2008)

Posted By Madstang on 05 Aug 2009 04:30 PM 
Ok, I heard the same thing, my question also is why would you make aboard that cannot be hooked up to 2 mu locs"???


So lets say I hook it up like the book says, so how do you wire 2 GP-9s'...if you place a board in EACH loco, which is not cost effective, by the books way you would have to have a battery power fee to BOTH engines, that EACH have 2 motors in each of them... as per the instructions??? Cause they do not reccommend connecting to the mother board.

Does that make any sense..my question still stands how would you mu 2 GP-9 together following the logic of the Airwire booklet...by the book you couldnd'nt run 2 locos that have 2 motors in EACH of the locos......

OK maybe if you ran a pass through one of the engines to the other engine to the motors....see my point..all the EXTRA work involved to get this accomplished..is it really worth it..just to control lights and 2 functions when most only trip the whistle and horn...maybe the hiss?!!

Oh yea I recieved the same info from Al, so what I needed was information on someone who has wired the NEW G-2 lke the OLD way, and if they had any problems. 

The old one was also reccommended NOT to hook it up the way most of us have been hooking it up, NOT guitting the electronics and I had no problems at all wiring it that way.

I never run smoke so I am going to dissconnect it maybe preventing the potential spikes. 


So my question still stands.......has ANYBODY wired the G-2 the old way? isolating the track pickups and connecting to one of the mu plugs on the motherboard that was used for track pick ups? If so have you had any problems????


Oh yea and be sure to wire the 6 amp diode on the old diagram cause if you cross the battery + - you will do damageto it like the old boar...no power getting to the engine..or worse...I also got that info from Al.
Thanks Greg

Bubba



I think I have a few answers:

Why does anyone make a decoder that cannot be hooked to 2 locos? Usually the reason is so that you do not run exessive current, and also the risk of the connections between the locos. These guys also want to make money, but another great reason is so you can control the locomotives independently. In DCC, it is almost NEVER the case to share a decoder between 2 locos. You use consisting to make 2 or more locos run as a unit.


Yep, it is cheaper to share a decoder with 2 locos if you want, and can accept that they will function as a unit when this is done... no question.

Al did say to me to tell you that you CAN hook it up the way you want, and I did inform him that your GP7 does not have a microprocessor-based regulator, but an older (and safer type) linear regulator.


So, go ahead and try it, and Al did ask to keep the voltage at 18 or less. He also said that CVP would try to support all of their customers, he did not say you would be voiding the warranty.

Go ahead and do it Bubba, you do not need to ask anyone else, Al at CVP should be the highest authority on how their products work. There is nothing radically different in the output circuitry on the new decoder.


Regards, Greg


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## pimanjc (Jan 2, 2008)

Bubba,
I have a set of SD45s [you have seen them run at Marty's], that both run off one airwire board. I connect two MU plugs to the airwire output, with one running to an MU on the front loco and the second running out the back of the loco to connect to the back loco. The way I do it, both locos are not running through one native board, but each separate loco is given the same power output from the Airwire board. 









Jim C.


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## Madstang (Jan 4, 2008)

So what you are saying and what I am hearing is that you "gut" the board that is inside the engine. Use the Airwire board for lights and such..correct?

I use the inharent board in the engine....and have never had a problem.

Bubba


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## pimanjc (Jan 2, 2008)

Bubba,
I also run through the inherrent boards. All lights run through the on-board PCBs. The Two MU leads simply give both locos the same input power.

You have email.


JimC.


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## Madstang (Jan 4, 2008)

Got'ca..Thanks Jim.

Bubba


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## Paul Burch (Jan 2, 2008)

I have run into a problem with the new G2 decoder that at least in my case is discouraging. I have always used CV6 which sets the throttle midpoint voltage to adjust the speed curve for matching locomotives.
It made it real easy. CV6 is no longer a valid CV in the G2 decoder. It now is very difficult ,if possible at all, to match some locos. I put a new G2 in my tunnel motor (USA SD40-2 drive) which before was matched to my SD45's. I had to go back and change all my SD45's. As far as I'm concerned removing this feature in the G2 is a step backwards. I have communicated to CVP about it and they have no plans to add CV6. I can only speculate that it was done to accomodate one or more of the new G2 features.


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## Greg Elmassian (Jan 3, 2008)

On the face of just this data (not knowing more), that sounds nuts. 

Now the QSI does not have CV6 either (it is an optional CV per the NMRA), but it has a number of built in speed curves that effectively change Vmid for you (basically you come out with the same thing, in fact you get more flexibility), plus a fully custom speed curve 

I mentioned this because there are alternatives to no Vmid CV6.... 

But the new G2 has neither Vmid, nor (even more unbelievable to me in DCC) custom speed curves... 

I did not realize there are no custom speed curves. 

So you can only match start and top speeds, not in between. 

Regards, Greg


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## Paul Burch (Jan 2, 2008)

Greg,
I didn't mention that the custom speed curves were also gone because I don't think very many people used them. But,yes,they are gone too. So now I'm looking at my fleet thinking when I buy new G2's which locos can I swap the receivers in order to keep the versatility that I now have in MU'ing locos. Or I buy G2's and swap for the older receivers with people who would like the new cruise conrtol feature, which is nice.


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## rmcintir (Apr 24, 2009)

There is only so much that can be crammed into a microcontroller. The trade-offs on keeping or eliminating features can be hard. In development of my own receiver I have hit those limitations myself as I considerer adding a cruise control function. I would have to give something up to accommodate the added program space requirements. I have only tested it as a feature by itself. In my own test I had to give up the speed tables for MUing, I missed them too much so I haven't gone beyond basic testing. Still thinking about how to fit it all in.


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## Greg Elmassian (Jan 3, 2008)

Russ, ram and micros are cheap. I cannot accept that statement to justify eliminating features that are NECESSARY for consisting. 

Paul, I know you are an AirWire guy, but could you use some of the QSI units? They only will run about 3 amps, but they are plenty cheap and have the features you want. I believe you can tweak the BEMF parts to be close to cruise control, but it is not as elegant as the simple cruise features on the AirWire, I will definitely admit. 

Regards, Greg


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## rmcintir (Apr 24, 2009)

Perhaps not in the case of a corporation with more resources to spend but jumping up to a more capable micro may be a 20-30% increase in price. That is significant in a field where margins are tight. Even if there is no change in price the retooling for a change may not be cost effective especially if most of the customers don't use a particular feature. I would hope that a version offering consisting capability is still available. 

Needless to say, I won't be getting rid of speed tables in my receiver. I like it too much and I agree with you, it is a necessary feature to consist dissimilar locomotives! I am however rethinking how I implemented speed tables to see if I can get some space back for other things. My first receiver version supported 256 loco addresses, 6 accessories, and 256 speed steps all in 256 bytes of program memory on a 4MHz micro. When I added Back EMF and speed tables that all changed and I bit the bullet going to a microcontroller that was twice as much money. I'm still cramming it into less than 2K bytes of memory. 

I better stop, I have been known to take threads off-topic and I don't want to do that!


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## John J (Dec 29, 2007)

I was thinking that they could make a auxiliary board with a H drive on it. No decoder. The Drive signals could come from the Decoder board via a Aux out put. That way you could have a A & B set up You could control the B unit from the A unit decoder and actually have a second set of batteries for the B unit.


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## Greg Elmassian (Jan 3, 2008)

The world of simplicity is rapidly fading JJ! 

The system uses BEMF, which means it is reading that from the motors (which is another reason to connect to the motors and not the main board), and it's possible that connecting another H bridge is not going to work well, i.e. can't read the BEMF from the second loco. This could affect the "newly beloved" cruise control feature. 

This is really a losing battle with the manufacturers, you have to start going with one decoder per loco. Reading the BEMF from multiple motors in the SAME loco is tough enough, I know, I'm pretty involved in this with another manufacturer. 

Regards, Greg


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