Lionel RS5 with no auto rpm sounds

This would be from memory, but I'll give it a shot. The cam switch was used in command mode as a confirmation of the motion/stop state. The RPM would rev up on the first throttle relative speed +up command, but if the cam switch didn't activate within about 5 seconds, the RPM would rev back down again.

 

The VCO I think was developed mostly for after-market, where people didn't want to bother/were unable to install a cam on the truck. But by its nature, the VCO is a less reliable indicator.

 

In conventional mode, you are correct--all you have to go on is track voltage and the cam, if present or a VCO.

 

I don't recall the exact chronology, but I think most Lionel product would have gone from cam switch to using the motor's optical encoder as the source for motion/stop detection. Perhaps John can tell us which sorts of Lionel product used a VCO, but I'd guess it was not so many. There was a powered motherboard that did use a VCO.

 

The current system is superior--even with a mechanical cam you'd only get 2 pulses per wheel revolution. And as low speed performance improved, the time between those pulses got too long to be a useful indicator. Getting the information from "a motor who knows" is best.

Rudy,  Thank you.  Makes sense.  I am always curious about how it works and evolved.  Not just that it does work.    G

I know the TAS and ERR boards used the VCO, and I remember seeing that on a TMCC motherboard that was Lionel branded.  I looked through my MB box and I don't see it now, but it had a couple of chips that I assumed were for the VCO.  It was certainly an older product.

 

I'm curious, you're saying that they're using the optical encoder, but that would only be for stuff with Odyssey, the non-cruise RS4 seems to just be using the serial data.

 

I have a test setup with a MB and the three standard TMCC/RS4 boards and the DCDR.  No VCO and no axle cam, and it manages to ramp the prime mover RPM.  The RS4 board is using the OEM-ALCO sound chips.  I assumed it was reacting to the serial data, I'm driving it with an old CAB1/BASE1 on a test bench.

 

Atlas with Lionel TMCC/RS used the VCO.  I have also crossed it to some Lionel RS4 engines.

 

Rudy said it uses Relative data in command.  So what your seeing on your set up is correct.  G

In conventional, If there is no cam or VCO, its possible just to ramp the rpm based on measuring the AC track voltage. And for an OEM TMCC/command version where no cam or VCO was present, the railsounds software would omit the behavior I described earlier, where a cam pulse was required to confirm motion a few seconds after a relative speed command.

 

As you can imagine, there have been many small (and some large) variations on how this stuff works over time depending on the needs of a specific product or product class.

 

-Rudy

I do see a lot of variety in Lionel stuff, so I suspect you could find almost anything if you look hard enough.

 

fyi. The Lionel motherboard used by K-line in the Pa-1 had a VOC.
691-PCB1-0B1 Rev B.
lionel may have used it in the SD-40-2 Diesel with Odyssey.

I found this solution to all TMCC locomotives from any manufacturer several years ago and it still aways works. When a TMCC/Legacy engine is selected in the DCS Handheld, the middle softkey is SPD. Select SPD then select 128. Now the rpm's ramp up and down on the TMCC engines.

You are correct Jack, that makes it look like the CAB1.  I suspect when MTH did this feature they didn't look closely at the oddities of TMCC diesel operation.

 

Pretty sure I tried this and it didn't work.  Starting to suspect an issue with this engine.  It doesn't change rev levels on my 990 either....

If it doesn't change with the #990, it's likely an issue with the engine, and not the control system.

 

Board issue John?

What specific engine are we talking about?  How about the Lionel model number?

 

6-31735 Lionel Chessie GP30 RS5

From breakup set

The VCO for that one should be on the Odyssey board, check the wiring from that board.

John, I think we are getting this topic confused.  I went back and read Rudys response, also what Bill said on Cruise M.

 

I am not sure why ODY motor board needs VCO when you have the tach input.  I thought VCO was a stop gap for cam less engines.  Plus it was only a confirmation signal.

 

Not sure why a ODY needs VCO when it has direct speed input from a tach.

 

Cruise M with back emf, maybe but again you have direct serial data speed command input.  I would think that the back emf and serial data would do, but who knows.  G

Ken says the Odyssey replacement CC-M has a VCO.

 

Jon used the term "VCO like" pulse for Cruise M.  As far as Lionel VCO on DCDS boards (ODYS), I don't know if it really is VCO or some other duty signal.  VCO is really oscillation frequency controlled by voltage, in this case Motor voltage.  Why add that when you have a tach pulse to use?

 

Would be nice to know more about it, but we are probably in the weeds on this.  Suffice to say diesels that had DCDS drivers need the Cruise M that outputs a duty out on pin 2.  Not sure why they all don't do it, since you don't have to use it if you don't needed it.  G 

All you need is a periodic pulse to keep the RPM up, I did some experiments with my bench test set.

 

I agree that it escapes me why they don't just put that signal out on all the Cruise Commander M models, then they'd only have to stock a single item.