khier SouthPenn This is what DCC should have evolved to by now.
SouthPenn This is what DCC should have evolved to by now.
This is what DCC should have evolved to by now.
greg - Philadelphia & Reading / Reading
gregc
Regards
Walid
Walid, you should be a politician. ABsolutely noothing you replied on diagreed with anything I said. I'm an enginner. Perhaps you are too, or at least have a decent math background. So yes, for US it is "child's play" to calibrate speed. Though I don't think BEMF is the way to do this. I very much dislike BEMF levels that result in cruise control where the loco runs the same speed up and down hills, with 2 cars or 20. But what about the rest of the hobby population, who don't know all that? Yes, there are plenty of locos already out there that have either interrupter wheels or Hall sensors used to sync the chuffs. Don't think any diesels have that (except maybe MTH) since they don;t have anything to sync with the speed. But as already mentioned - there is no mechanism in DCC to get that information back to the THROTTLE. Railcom and Digitrax Transponding allow for this, but you have to be much more careful in wiring the layout for it to work completely reliably. The signal from the decoder is very tiny, because it is transmitted using stored energy, the command station uses a quiet time with no signal (and thus no power) to allow the decoder to signal back. Similar to the concept of X10 sending a signal at the zero crossing of the AC power for home automation.
But then the last one - perfect example of taking a quoite and cutting it off to make it out of context. I do NOT like pushbutton speed control. Never said I did. The idea of pushing a button up to 126 times to get to full throttle is just silly to me. What i SAID was, pushbuttons for speed control might be ok, if you only have 28 speed steps. NCE systems defult to using 28 speed steps for control. You can change to 128, but there is no way to make it default. Digitrax systems default to 128, but you can set it to default to 28 or even 14 if you really want to for some reason.
It all comes down to lack of interest - you're sure big on a better throttle, but obviously not enough people are. There's been nothing preventing anyone who wanted to from developing a completely different type of throttle for at least 10 years now. There's even been an open protocol that works with any DCC system that you can connect JMRI to. MRC, Digitrax, and ESU are using it with their latest devices. But it's been around for several years now. If there was such a demand for a better control unit, surely someone would have stepped in to make all the money just waiting out there. Plenty of people with the ability have done DIY units, and shown others how to replicate that. But no commercial interest. I think you greatly overestimate the size of the market. I too wish everyone were into model railroading, but the truth is, this is a rather small hobby. And DCC is just part of that. If you look back when DCC was first introduced, half the companies that were selling systems have evaporated. There were too many for the market to bear. If DCC vendors sold millions of systems a year like smartphones, then we would indeed have $50 throttles with color displays and every other usability aid. But they don't, so we don't.
--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,
First and foremost my apology if my words and style seemed offensive or aggressive. Typed text creates a different impression than words spoken face to face.As for the speed feedback, I have never meant measuring the speed and sending back to the command station. All I meant a scaled indication of speed. Instead of 10%, 20%, 50%, 20, 40 and 100km/h if I set the maximum speed to 200 km/h.When you raised the speed feedback issue I responded with possibilites of how manufacturers and/or electornic freaks could easily introduce a speed it. It was a response to your point not mine.I fully understand your comments regarding the push bottons. Perhaps I could not express myself clearly. I said even for the 28 steps push bottons is something that belongs to the past.
Although I mentioned it earlier I will repeat it again: I am NOT trying to convince anyone what to like or dislike. I am NOT trying to tell anyone what is right or what is wrong. As I said before, there is neither right nor wrong in the hobby. Everyone uses what makes him/her feel comfortable and let him/her have fun. I do respect all opinions even those I disagree with. All I wanted is to hear what others think rather than to prove anything, but I had the feeling all the time that you are trying to prove a certain view.RegardsWalid
khier Graffen Railpro is a proprietary system. Too bad. I started to like the controller already. Walid
Graffen Railpro is a proprietary system.
Railpro is a proprietary system.
Too bad. I started to like the controller already.
RailPro runs on DCC systems. I have an NCE power pro system and I run RailPro on the same track at the same time.
I find that I run the RailPro engines a lot more often than the DCC engines. My plan was to only install RailPro in engines that had no decoders at all. That plan went out the window. I am slowly replacing my DCC decoders with RailPro.
Khier
I think having actual scale speed showing on the controller might be hard to do. The decoder would have to know the gear ratio and wheel size. ( even more CVs ) Also the exact motor RPM then do the math.
SouthPenn Khier I think having actual scale speed showing on the controller might be hard to do
I think having actual scale speed showing on the controller might be hard to do
Well when people tell me it can't be done and I know I can do it, I kind of take it as a personal challenge. I'm going to use the WiThrottle protocol, which I'm guessing is also compatible with LNWI. I'm reasonably certain I can do the loconet protocol and make it a plug in throttle. But first things first.I ordered the parts and already started a case on tinkercad. I'm making it open source. I'll start a thread when I have primary renderings done and look for feedback from the community. Expect a thread in two weeks.I'm adding tactile buttons, a screen, and optical encoder.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Counter-electromotive force is proportional to motor speed and is measured by many decoders.
Couldn't a scaling value stored/set in the decoder be used to translate BEMF to scale speed?
The decoder needs only to know the number of revolutions a wheel rotates (or the motor rpm) and translate it in speed using an input stored in a CV.
That works as long as the wheels don't slip like when on a grade. Perhaps we could automobile technology to get a more acturate reading of speed and possibly stop the train if there were something in the track like a curious cat or a miniputean.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
SpaceMouse The decoder needs only to know the number of revolutions a wheel rotates (or the motor rpm) and translate it in speed using an input stored in a CV. That works as long as the wheels don't slip like when on a grade. Perhaps we could automobile technology to get a more acturate reading of speed and possibly stop the train if there were something in the track like a curious cat or a miniputean.
DigitalGriffinBEMF uses variations in the current. It is a little less accurate, but works.
huh? From Counter-electromotive force
The term back electromotive force is also commonly used to refer to the voltage that occurs in electric motors where there is relative motion between the armature and the magnetic field produced by the motor's field coils, thus also acting as a generator while running as a motor. This effect is not due to the motor's inductance but a separate phenomenon.
This voltage is in series with and opposes the original applied voltage and is called "back-electromotive force" (by Lenz's law). With a lower overall voltage across motor's internal resistance as the motor turns faster, the current flowing into the motor decreases.[4] One practical application of this phenomenon is to indirectly measure motor speed and position, as the back-EMF is proportional to the rotational speed of the armature.[5]
In motor control and robotics, back-EMF often refers most specifically to actually using the voltage generated by a spinning motor to infer the speed of the motor's rotation for use in better controlling the motor in specific ways.[6]
Chip , you haven't been gone from PA THAT long to have forgotten about going 40 on the snow and ice and your car isn't actually moving.
Don - this is something I was thinking, but I have too many projects on my plate. WiThrottle protocol is best, it's simpler than Loconet plus it wil work with the Digitrax Wifi interface, the MRC wifi interface, and any other system, that works with JMRI.
My other idea would be something like a combination app and phone case, the app would display plain text buttons for functions, the case would incorporate a throttle knob that would interface via Bluetooth. If the part that fitted around the phone and the part holding the electronics and the knob would have some sort of physical connection, you could just make different case parts for different brands and models of phone without changing the expensive electronics part. Sort of like the ESU Cab Control throttle, but the screen part would be using your own smartphone, Android or iOS. Cost would be for the knob and BT interface, using the phone you already have. Also using WiThrottle protocol to make it universal.
DigitalGriffinYour car would give a false reading on the speedometer too if it's wheels slipped.
rrinkerChip , you haven't been gone from PA THAT long to have forgotten about going 40 on the snow and ice and your car isn't actually moving.
I was refering to the sensors that govern speed and proxemity to obstacles and control automatic braking, cruising distance, and limits road-kill points in crosswalks, not to the cable that runs to the back of the dashboard.
gregc DigitalGriffin BEMF uses variations in the current. It is a little less accurate, but works. huh? From Counter-electromotive force The term back electromotive force is also commonly used to refer to the voltage that occurs in electric motors where there is relative motion between the armature and the magnetic field produced by the motor's field coils, thus also acting as a generator while running as a motor. This effect is not due to the motor's inductance but a separate phenomenon. This voltage is in series with and opposes the original applied voltage and is called "back-electromotive force" (by Lenz's law). With a lower overall voltage across motor's internal resistance as the motor turns faster, the current flowing into the motor decreases.[4] One practical application of this phenomenon is to indirectly measure motor speed and position, as the back-EMF is proportional to the rotational speed of the armature.[5] In motor control and robotics, back-EMF often refers most specifically to actually using the voltage generated by a spinning motor to infer the speed of the motor's rotation for use in better controlling the motor in specific ways.[6]
DigitalGriffin BEMF uses variations in the current. It is a little less accurate, but works.
DigitalGriffinDecoders can't measure the motors magnetic field.
they don't need to. electromotive force is a voltage. the decoder measures the voltage produced by the motor with the drive circuit momentarily turned off.
when a voltage is applied to the motor with it not turning (stalled), the current is limited by resistance. The currrent produces a force when in a magnetic field causing the motor to rotate. When the armature rotates in the magnetic field a voltage (EMF) is produced.
This back EMF counters the voltage supplied by the decoder, reducing the current (Ohms law) and the force causing the armature to rotate. equilibrium is reached at some speed. If the speed decreases, the BEMF decreases, current increases and force increases. If speed increases, BEMF increases, current decreases and force decreases.
the current varies with the load on the motor. The BEMF is proportional to speed and measurable.
why would they call it BEMF if they are not measureing BEMF?
The BEMF calculation only gives you motor RPM. You still need to account for the gearbox ratio and wheel diameter.
SouthPennThe BEMF calculation only gives you motor RPM. You still need to account for the gearbox ratio and wheel diameter.
yes. But measuring the speed of the motor is the hard part.
you could calculate and program a translation value into the decoder (and command the loco to run at a specified speed).
gregc DigitalGriffin Decoders can't measure the motors magnetic field. they don't need to. electromotive force is a voltage. the decoder measures the voltage produced by the motor with the drive circuit momentarily turned off. when a voltage is applied to the motor with it not turning (stalled), the current is limited by resistance. The currrent produces a force when in a magnetic field causing the motor to rotate. When the armature rotates in the magnetic field a voltage (EMF) is produced. This back EMF counters the voltage supplied by the decoder, reducing the current (Ohms law) and the force causing the armature to rotate. equilibrium is reached at some speed. If the speed decreases, the BEMF decreases, current increases and force increases. If speed increases, BEMF increases, current decreases and force decreases. the current varies with the load on the motor. The BEMF is proportional to speed and measurable. why would they call it BEMF if they are not measureing BEMF?
DigitalGriffin Decoders can't measure the motors magnetic field.