When I try setting up a momentum value for any loco on my Power Cab I get prompted to type a value between 0 and 9. But whichever value I type in, nothing happens.
What should be done to get that work properly ?
Martin 4
Martin,
The only decoder I have that doesn’t seem to take momentum changes from my Power Cab are Loksound. (I have to manually enter values into CV 3 & 4 to accomplish that.) All others (e.g. TCS, Digitrax) I don’t have that issue.
You might try cycling power to see if that works.
Tom
I have a handful of diesels with loksound and I have not any problem using momentum. NCE writes to CV 3 & 4 to do that. My layout is not wired up at present to test if you need to cycle power, at the moment.
After continuing testing I found a few minutes ago that the momentum function is working. What is confusing is that no value appears when setting it up as if nothing was happening.
You have to know that a level of momentum has been applied and remenber the value. Or set up the momentum each time you want to be sure of applyint it.
Martin 4
The Power Cab only asks you to enter a value of 1 through 9 (0, being the default) for the momentum level after pressing the MOMENTUM button. If there is a delay in starting out/slowing down then the values in CVs 3 & 4 have changed. You have to read the values of those CVs and divide by 8 to determine the actual momentum setting of your decoder. I generally keep the momentum value of my locomotives about the same - i.e. 16 or 24; that’s 2 or 3 using the MOMENTUM button on the Power Cab.
Tom
It’s against my nature and maybe everyone else, but you should keep what you change on each locomotive. Six months later you will have no idea.
I think the momentum is not applied to the decoder setup; it is a momentary feature.
Actually, it is applied to the decoder, Martin. And to confirm that I ran a little experiment.
I took my Walthers SW7 switcher and checked the momentum CVs (3 & 4) in programming track mode. Each had a value of “24”, which is equivalent to “3” using the Power Cab momentum button. Using the Power Cab I changed momentum to “5” and CVs 3 & 4 each showed a value of “40”. I cycled power, turned the Power Cab back on, and checked CVs 3 & 4 again. Their values were still “40”.
So, whether you use the momentum button or manually change CVs 3 & 4 to increase or decrease momentum, the CV values are retained in the decoder…until you change it to something else.
Tom
Thanks for the info Tom.
So CVs 3 and 4 are modified even without being in Program Mode ?
Martin 4
Correct. You can change them in either programming track mode, programming on the main mode (POM), or “on the fly” using the momentum button on your Power Cab. The locomotive will come to halt though if you perform the latter and it is already moving. It will then resume the set speed step using the new momentum values.
Tom
I generally agree with this. However, in terms of momentum, I think NCE made it so easy to regularly change momentum so you can alter it based on the size of train you are about to pull. Since the accel/decel values are roughly equivalent you shouldn’t get into a pickle running an engine you haven’t in some time. Just take note of how fast it takes off. If you do get in a tight spot, press the emergency stop button.
As mentioned, I generally enter a momentum of 2 or 3 for my steam & diesel locomotives. All I’m looking for is the gradual/delayed transitions into the speed steps. I can mimic my own overall momentum by just using the fine speed buttons on my Power Cab.
Tom
that’s interesting. thanks for doing/reporting this experiment
i would have thought it wouldn’t be difficult for the power cab to simply send in/decreasing speed values.
it could have done something similar if there were grade buttons
Do you need ESU’s proprietary software to read CV values? Lokprogrammer is it called?
No. You can read CVs by using the Program Track mode.
I have not really changed much on my locos. I run the NCE Power cab. Does changing the momentum setting change the rate of increase or decrease in the speed of the loco? So if you want to keep your locos from jumping into movement do you set the momentum at a higher level? Does higher momentum also mean that the loco will also take longer to respond to a reduction in speed thereby increasing the stopping distance needed? Thanks wdcrvr
Yes, that’s it. You set the acceleration and deceleration separately.
I really like it. I have mine set fairly high. I can put in the top speed I want for the train and watch it start with a crawl and slowly reach the top speed. I like that.
I imagine some others would not like it, and would like to control each speed increase.
As Mike mentioned, the deceleration may make control a little difficult, but you can stop the train immediately by pushing the emergency stop button.
Correct. Momentum increases the amount of time it takes to accelerate or decelerate to a given speed or come to a stop. So, the larger the value; the longer it takes your locomotive to speed up and slow down. And you can add as little or as much momentum as you want…or none at all. You can also program the CVs separately so that you have more momentum starting out than slowing down or vice versa.
Tom
When using momentum it is wise to find the F key for the brake. Often it’s F10. The emergency stop button stops everything.
In DC powerpacks equipped with momentum effect you benefit from the red brake button. You could ask how I know this…
Tom, you have obviously mastered the momentum feature on the Power Cab. Thanks for all your input. Although my DCC system is the wireless 5 amp Power House Pro, I am often tempted to add a Power Cab for its added versatility.
Rich