Hi!

You always get AC out of a transformer. It's not a transformer when you get DC. You get AC out of the 66470.

The CS2 should always provide the full voltage, but the polarity changes. Some call this "bipolar pulsed DC". Polarity changes, so it behaves like AC to some extent.

The ECoS with RailCom or SX enabled will sometimes turn the track voltage off. Otherwise it is "bipolar pulsed DC" like the CS2.

The polarity changes convey the instructions, therefore the polarity changes have a complicated pattern, no fixed intervals.

I did a Drongo thing last night. While double heading a pair on analog class 23 steamers, I stupidly changes some switches that sent that analogue consist right through a digitally controlled section of track and back onto its own analogue control. I didn't notice what had happened untill it was too late, and the amazing thing was , there didn't appear to be any change in the locos behavior. The original big blue 280 transformer was set at half throttle.
It gave the MS2 a fright though because I then could not get the digital loco going. Its lights were on but no response. I noticed the MS2 had reverted to the points controlling display, so I unplugged it thinking I had stuffed it. Plugged it back in and all went back to normal.
Was I lucky????

Not an answer to your question but it suggested the voltage had not been much different. We should put volt meters on to see. Too much panic last night to think about that.

Dereck

Just to confuse the issue some .....

DC is direct current - a DC signal has a fixed voltage relative to a reference (ground) - that fixed voltage could be positive or negative, but is fixed.
DC driven motors use the voltage to affect power/speed - so moving the voltage to reference(ground) would slow down the motor.

AC is alternating current - and thats a very broad term electrically speaking (I don't know what assumptions hold in the Märklin world when using the term AC).
For AC, the voltage changes over time. There is no polarity, there is only the phase shift, and that would only be meaningful in relation to a reference AC signal or some other signal. We traditionally think of AC as sinusoidal - such as what comes out of the power mains on the wall, or the 3 phase stuff from the power poles.. .its 50hz or 60hz depending on where you live in the world.

But something like a square wave... thats AC, and depending on how you look at it (the duty cycle of the square) you could call it DC for very short time intervals.

Then take a sinusoidal AC signal, and modulate digital data on top of that sinusoidal signal (or modulate digital data on any AC signal) .. and its a mixed bag that is still AC at its core with some DC components in it as well.

Originally Posted by: dominator Go to Quoted Post
Was I lucky????
Maybe. There should be centre rail rockers in place when trains transition between analogue and digital parts of the layout. Otherwise this can be fatal to digital components.


Hi Tom. Could you please explain what the centre rail rockers are. What happened to me was stupid because I was attempted to load a lot more wagons behind my latest 3098 to test for wheel slip. In the end itpulled "like a train".
Dereck

Wow Soren. That is so easy and simple to do. Many thanks.

I think you will save someone else's bacon with that advise.

Dereck

In the case of MM, mfx, and DCC it is theoretically always full voltage, just with alternating polarity. But there is no sine wave and the controller does not vary the voltage to transport information.
SX and RailCom have full power with alternating polarity or no voltage.
The data packet that is shown in close-up does not have the 0 V line showing.

Your diagram shows the pattern for the MM protocol. DCC is different, mfx is different.

There are rectifiers inside most units, so you get about 22 V track voltage from 16 V AC input voltage.
With DC input voltage the track voltage will be lower than the input voltage.

Some Märklin decoders (6090x and probably 6090 also) reduce their speed when voltage is lower.
CU 6021 and booster 6017 have a DIP switch that reduces track voltage, allowing you to create slow-speed sections on the layout.
Newer Märklin decoders do not support this.


BTW: Your diagram nicely illustrates why 16 V smoke generators can be used on digital layouts: they are wired in such a way that they only get the "-22 V" from your diagram, not the "+ 22 V". This reduces the effective voltage that goes to the smoke generator to an acceptable level.

Nothing has changed since the 6020: inside the controller there is DC and there are transistors that will route the DC to the track in an "all or nothing" fashion, creating a rectangular wave with alternating polarity.

MM, DCC, and mfx use different patterns to encode the 1s and 0s that are transported and how they are grouped to commands (data packets).