I 've got a QSI quantum engineer which i've used for a while and a Digitrax dcc -zephyr xtra -(new) . The engineer has a brake apply and brake release function - two buttons , this feature is excellent and controls the loco well . My question is How can I make the digitrax behave the same way ? The brake feature is what sets the engineer apart from the dcc system .
ps - It's a QSI chip in the loco , Walthers E8 .
Thank you.
John.
The Zephyr has a brake position between the forward and reverse. It slows the loco when on and releases when you select forward or reverse. You can use it without changing your speed setting on the throttle. It will slow the engine whenapplied and return it to the throttle setting when released.
Joe
Joe, Can the Zephyr throttle be adjusted while the brake is applied?
No, it's an either on or off deal.
Joe, if the throttle is left open when the brake is applied, what happens if the throttle is closed with the brake still applied? Will the train stop sooner?
To activate the brake in the DECODER, which is what the Quantum Engineer is doing, use use function F7 in DCC. That;s not the same as the Zephyr brake handle. The brake handle works like the simple brake handle or button on some of the fancier transistor power packs - once the level is in the brake position, the train slows down, regardless of what you do with the throttle.
--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, does F7 require that the throttle be turned down all the way?
Not with QSI, the loco will slow down regardless of the throttle position. If you take F7 off, and the throttle is still higher, it will speed back up again.
Randy, does F7 toggle off? That is, pushing F7 again releases the brake action.
Yes, F7 is a toggle function, F2 for the horn/whistle is the only momentary one by default. Some Digitrax throttles let you also make F1 (commonly bell) momentary as well, since before the de facto convention of F2 for horn was established, some decoders used F1 for horn and F2 for bell.
Thanks for the reply.
I know that the Zephyr has a brake position , Its just so lame compared to the Quantum Engineer. When i push the brake apply with the QEngineer the loco will stop quick . if i interupt brake apply with brake release it goes into a coasting mode with no acceleration . You can alternate between brake apply and brake release and come to a nice slow stop at the station. With the zephyr if you apply the brake it doesn't seem to slow that much and accelerats when going back into forward , I do like the DCC except for the lack of a proper brake function. It seems to me that the QEngineer mimics the brake action of a real loco better than the Zephyr , and that is what I want with the Zephyr , any suggestions.
John
That's what the F7 function will do. You do not use the brake position on the direction handle, but activating F7 will cause the loco to slow down, turnign it off goes back to the coasting mode. The Quantum Engineer is activating those DCC functions while using DC, you can access the saem functions natively in DCC. If you didn;t get one, there's an operation smanual that would explain this and other available functions, you should be able to download a copy. Not the giant Quantum Reference Manual that explains every CV and setting, this should be in the more basic manual that just explains what the functions are. The big manual is useful if you want to modify the operation as it explains every CV and possible setting in extreme detail. Usually it's easier to get a computer interface and use JMRI to do the complex programming.
For DC control, realistic brake action was worked out and explained in Model Railroader, August 1968. Somehow, the message has not come down to those who develop DCC decoders. I was disappointed that the new QSI "Titan" decoders do not go the extra distance to realize realistic brake action.
Realistic brake action may not seem to be an issue, but sound systems won't lip-sync properly until brake functions are correct.
What won't sync? Most any sound decoders has a cam input option to absolutely sync stem loco chuffs at ALL speeds, not just exact at one point ant 'close enough' at another. Some have rod clank activeated by the reduced load on the decoder, such as when descending a grade, and chuffs cut out when the brake is applied. The braking action is dependent on throttle position.
Despite the electronic simulation, REAL brake action will NEVER happen in models - because physics does not scale. Even using spur gearing or multiple screw worms so the loco can cost withthe power off won't give proper braking. At best you can simulate the independent. Sure those TAT throttles sometimes had a seperate train brake and indepdnent brake, but all it ever could really do is simulate the independnet, because all braking and power force comes from the locos. I always had a fantasy idea to have a flywheel caboose with an electric brake that would simulate the train brake, but such a thing would barely be feasible in O scale, let along anythign smaller. Perhaps in large scale it would actually work as expected. Coupel this with a free-wheeling loco, with a similar brake to be the independent, and you might get close to 'real' train handling.
You can do almost anything with electornic simulation, but it will never be more than a simulation. There's at least one modelr who has made a brake stand replica using an NCE throttle. With the features in a Tsunami decoder, there are 8 notches on the throttle plus a working brake. It should be possible to do this with QSI decoders as well, they have a brake function as well. There is a Youtube video of it in use running a switcher in a yard. I don;t think any TAT throttle can do any more than what that does. Getting a good loading up effect with a train attached is about the only place Tsunamis fall flat, QSI makes this very easy without resorting to manual notching simply by adding momentum, accelerate slowly and the loco moves off without loading like it would in a light engine move, crank the throttle and the train moves off slowly but with the engine revving up first. In steam, the Tsunami seems to be able to do labored chuffs as well as the rod clank solely on the actual load, sensed via BEMF - climb a hill, the loco works harder, coast downgrade, the cuffs die off and you hear the rod clanks. Seems pretty realistic to me.
What won't lip-sync is simulating working the throttle against the train brakes. This was a flaw in the otherwise True Action Throttle (TAT). The throttle circuit was cut out when the brake was applied. This is not a problem for switching, using the independent brake, as the throttle would be closed before the independent brake is applied. However, when braking a train, the train brakes would be used to keep slack stretched. This is described in the introduction to "Designing the Maumee Route" by Bill Darnaby (Model Railroad Planning 1995, pg. 58). "...exhaust beats distinct but slowing. You can actually hear the engineer bringing his train under control...". The throttle is being worked against the train brake to keep slack stretched.
Dennis Blunt added brake circuits to the TAT to simulate brake action with the throttle open and installed these circuits in half size replicas of brake valves (Model Railroader, August 1968). This allowed the throttle and the brake to adjust deceleration. While sound systems were being developed, it is not known if anyone rigged a sound system to such a modified TAT. This would have keyed the exhaust sound to the throttle setting for better lip-sync.
As it is, DCC decoders do not allow the throttle to work against the brake, so Darnaby's drama would lack accurate sound with DCC decoders.
Hi Randy
Thanks for the quick reply.
Yes the f7 works , I have used it with the zephyr. I was hoping there was a setting that would give f7 more authority , like the engineer. The engineer just stops quicker if the brake button is left on and the coast feature is superior . The stopping is slower with Zephyr when using the f7 and the coasting doesn’t seem to work with the f7 off , the loco just stops , anyway thank you for the info and i do have the manual that came with the set.
Thanks again.
To get coasting in DCC you need to set CV3, acceleration and CV4, deceleration, to some non-zero value.
Don;t go too high, start low, 5 or less, to get the feel for it, or it may appear the loco is out of control.
Nice thing with QSI, if you have CV3 set to some value, you can crank the throttle wide open and the loco will slowly gain speed, in a diesel it will rev the motor like it's trying to start a heavy train, on the steam it will produice more labored chuffs. You cna back off as the loco reaches the desired speed and it won;t go any faster. With CV4 set, you can quickly close the throttle and the loco will slow down gradually. Use F7 to apply the brake and the loco will stop quicker.