....I suppose so..
Over50 richhotrain Over50 Have to say knowing what I've now learned in hind sight I shoulda' saved my self the money and gone with just AR1's for the (2) reverse loops and be done with it. That is what I have been thinking as I follow this thread. Digitrax sells all of that complicated circuitry, but, in my opinion, less is more. I have an NCE PH-Pro 5 amp system with only one booster, no circuit breakers, and five AR-1's on my layout which is 25' x 42'. I cannot help but agree with you that the two AR-1's without the PM42 would have served your needs just fine. Rich Yeah, I've come to this conclusion. Looks pretty all lit up .... and everything appropriately complicated to brag about.....but........ The word that comes to mind is overkill. But, if I can resolve the chase problem with one last change to the DB150 I'll stick with it. If not, the (3) PM42 section A and B outputs are fed to a terminal strip within 6 inches of the DB150 and all it would take is make up some jumpers to feed the (3) track sections and leave the PM42 in place so I don't lose it....
richhotrain Over50 Have to say knowing what I've now learned in hind sight I shoulda' saved my self the money and gone with just AR1's for the (2) reverse loops and be done with it. That is what I have been thinking as I follow this thread. Digitrax sells all of that complicated circuitry, but, in my opinion, less is more. I have an NCE PH-Pro 5 amp system with only one booster, no circuit breakers, and five AR-1's on my layout which is 25' x 42'. I cannot help but agree with you that the two AR-1's without the PM42 would have served your needs just fine. Rich
Over50 Have to say knowing what I've now learned in hind sight I shoulda' saved my self the money and gone with just AR1's for the (2) reverse loops and be done with it.
Have to say knowing what I've now learned in hind sight I shoulda' saved my self the money and gone with just AR1's for the (2) reverse loops and be done with it.
That is what I have been thinking as I follow this thread. Digitrax sells all of that complicated circuitry, but, in my opinion, less is more.
I have an NCE PH-Pro 5 amp system with only one booster, no circuit breakers, and five AR-1's on my layout which is 25' x 42'.
I cannot help but agree with you that the two AR-1's without the PM42 would have served your needs just fine.
Rich
Yeah, I've come to this conclusion. Looks pretty all lit up .... and everything appropriately complicated to brag about.....but........
The word that comes to mind is overkill.
But, if I can resolve the chase problem with one last change to the DB150 I'll stick with it. If not, the (3) PM42 section A and B outputs are fed to a terminal strip within 6 inches of the DB150 and all it would take is make up some jumpers to feed the (3) track sections and leave the PM42 in place so I don't lose it....
Yep, I know what you mean. I have lighted signals next to every turnout and a corresponding LED next to every DPDT switch on a series of control panels that are installed along my layout.
As you say, it sure looks pretty.
Hey, maybe that's all that counts.
Alton Junction
Yes, extending the trip delay on the DB150 should fix it all up. The key is that the device you want to operate first needs to be the fastest and/or most sensitive, on up the chain. The default sntadard setting on the PM42 is faster than the default settings on the DB150, so it works. But the Slowest setting on the PM42 is about the same as the DB150 default, so it's a race as to which flips first.
I don;t have any reverse loops, so my PM42 worked right out of the box, all I did was set a board ID (which determines the address of the board - you can actually turn sections on and off from your throttle, plus when a breaker trips, it reports that over the Loconet. My plan is to just have some indicators on a JMRI panel that light up indicating a short, not that it isn;t pretty obvious. Well, that was my plan, until I had to take down a part of my layout..
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker The only danger now, if you have the PM42 on the slowest setting, is that it might trip the command station breaker before the PM42. If that happens you cna change the behavior of the command station to trip slower so that the PM42 always trips first. That's in the section at the back of the system manual where it lists the OpSw settings. --Randy
The only danger now, if you have the PM42 on the slowest setting, is that it might trip the command station breaker before the PM42. If that happens you cna change the behavior of the command station to trip slower so that the PM42 always trips first. That's in the section at the back of the system manual where it lists the OpSw settings.
And right you are Randy. After seeing your post I checked (short test) the (2) PM42 sections I slowed the sensitivity last night and, yes, the DB150 is triggering before the PM42 on those two sections so will make the change with the DB150. Why do I get the feeling I'm chasing my tail here.....
Have to say knowing what I've now learned in hind sight I shoulda' saved my self the money and gone with just AR1's for the (2) reverse loops and be done with it. This layout isn't much larger than the largest of all my previous DC layouts and I never did run into a track short problem over the years. But everything I'd read in my "homework" on DCC and in particular how less forgiving it is than DC - including multiple track feeders to allay signal degradation I figured I'd err on the side of caution and set up my layout with short protection also....do it right so to speak. As was a common statement in my working life experience methinks I over engineered things a bit.....
rrinker Sounds like you are good to go then. Each area trips properly, and does not affect the other zones. Exactly how it's supposed to work. Passing the quarter test everywhere also indicates you have adequate bus and feeder wiring. --Randy
Sounds like you are good to go then. Each area trips properly, and does not affect the other zones. Exactly how it's supposed to work. Passing the quarter test everywhere also indicates you have adequate bus and feeder wiring.
Well.....I thought I was good to go, too.....until I ran some of my other new engines that apparently drew more current at the same relative speed as the one - and only - engine I had been testing with and when the new/different engines tripped the AR1 the PM42 tripped again.
Tried adjusting the one particular AR1 but the pot had to be so near the minimum current trip setting (full CCW) I couldn't find a consistent sweet spot, where half the time either the PM 42 kept tripping or the AR1 chattered when this or that engine was run through the loop (one engine only at a time).
So.......got out the book and started reading the DT402 operation section in earnest in tandem with the PM42 instructions on how to change the two relevant PM42 sections trip sensitivity then gave it a shot.
Darned if the instructions weren't spot on and with book in one hand and the DT402 in the other hand and after plugging it into the PM42 and setting the required jumper for OpSw changes I managed to successfully change the trip settings of sections 1 and 2 to the slowest trip sensitivity!
So far since the PM42 hasn't tripped with any of (5) new DCC engines I bought entering or leaving either return loop (if it does I'll be on the phone with Digitrax...).
Hey, I was on a roll now so next I thumbed to the SEB/DT402 address programming instructions and I'll be danged I got all (5) of the new engines set up for 4-digit address access - and it works!.
rrinker The PM42 does not multiple current though, so just because each section may be set to trip at 3 amps doesn;t mean you now have 12 amps to the track, if you are feeding it from a single 5 amp booster. --Randy
The PM42 does not multiple current though, so just because each section may be set to trip at 3 amps doesn;t mean you now have 12 amps to the track, if you are feeding it from a single 5 amp booster.
Yup, I'm aware each of the (4) default PM42 sections 3 trip amp levels (or whatever it is set to) aren't accumulative but well and good that you mentioned it as a heads up.
Just to mention all (3) of my PM42 short protected track sections passed the quarter test including inside both AR1 powered areas, and having taken pains to ensure which rails were A and B during the wiring I've had no phase issues passing from one to the other.
You've effectively accomplished the same thing as adjusting the PM42 and leaving the AR1 alone - as long as the reversing device trips before the breaker, and that trips before the command station - you should be good.
With an AR1 driving a reverse loop, downstream from a PM42, which is then downstream from your booster, you have 3 devices which detect shorts and act on them. The default settings for a PM42 allow for it to trip before any of the 5 or 8 amp booster. The AR1 as you've notived has a simple potentiometer to adjust the trip current. The PM42 si programmable through OpSw settings, as are the Digitrax boosters, so you can always get a combo that works as intended - shutting down just the section of the layout with a short without killing the entire thing.
Just to note, since I lowered both AR1 trip point pots to just up from full CCW position the random PM42 trip problem hasn't occurred since entering or leaving either return loop and I've run the engines into and out of each loop both ways multiple times. Don't want to count my chickens too soon but it appears this solved the problem...
richhotrain I am not all that familiar with the PM42, but I do have several AR-1 units on my layout. My question is, why do you need both, or do you? Isn't the PM42 an auto-reverser, at least in part? So why use an AR-1 in addition? Or, alternatively, why bother with a PM42 if you have an AR-1 controlling the reversing section? What added benefit do you get from the PM42? Rich
I am not all that familiar with the PM42, but I do have several AR-1 units on my layout.
My question is, why do you need both, or do you?
Isn't the PM42 an auto-reverser, at least in part? So why use an AR-1 in addition?
Or, alternatively, why bother with a PM42 if you have an AR-1 controlling the reversing section? What added benefit do you get from the PM42?
Rich...
To address your questions, the PM42 has (4) outputs where each can be configured (jumpers) for short protection OR auto reverse but not both for any given section output.
I configured my 15' x 16' layout in (3) electrically isolated short protected sections using (3) of the (4) PM42 outputs, with (2) of the protected sections ending in return loops but connected by a long run between them with the center point as the end of protected section (1) and the start of protected section (2).
The third section of my layout is a 36 foot long out and back design that begins and ends off of the larger of the two return loops (section 1) and why I chose to electrically isolate it for circuit protection with a 3rd PM42 output.
Just to add, Digitrax recommends using a separate AR1 (or multiples) downstream from a PM42 output to provide short protection for trackage inside AR1 powered return loops.
To give you a better visual idea this is a link to a February 2012 forum post with some pics of my layout at the time including my drawing (since slightly modified but essentially the same overall). Kinda' messy but at this point I was in full roadbed and track laying mode with all the requisite crap scattered atop the benchwork...(smile)...
rrinker Switch mode on the throttle means pressing the Switch button on the throttle, liek you would use to operate a turnout via DCC. Don't forget that the PM42 will only respond if the program jumper is on. --Randy
Switch mode on the throttle means pressing the Switch button on the throttle, liek you would use to operate a turnout via DCC. Don't forget that the PM42 will only respond if the program jumper is on.
Thanks, Randy. I just saw/read that with the SEB manual pictorial of the DT402 button explanation. It's starting to make sense to me but obviously I have a lot of reading to do beyond the quick start information as I said ....
I set one AR1 trim pot to full CCW and ran an engine into the loop to the sound of the AR1 clicking multiple times, so moved the pot slightly CW each time until only one click entering or leaving the loop - and after repeated run-throughs into and out of the loop from different directions and no PM42 tripping I moved to my 2nd AR1 and did the same thing, with no PM42 tripping with either AR1 now. Hopefully just adjusting the AR1's has solved my problem - and thanks again Martin for the suggestion.
Now it's time to sit down with a cup of coffee and start reading beyond the Super Empire Builder quick start instructions.....
Again, thanks Randy and Martin for taking time to reply!
mfm37 Have you tried adjusting the AR1? All of my AR1's are down range of my PM42's. The AR1's work well using the default settings of the PM42's. The AR1's did take some adjustment to get them working every time. In Digitrax parlance you need only to know that Thrown is accomplished by pressing the T button and Close is the C button on your throttle. No need to worry if you push the C or T button and the Op switch was already set that way. Martin Myers
Have you tried adjusting the AR1? All of my AR1's are down range of my PM42's. The AR1's work well using the default settings of the PM42's. The AR1's did take some adjustment to get them working every time.
In Digitrax parlance you need only to know that Thrown is accomplished by pressing the T button and Close is the C button on your throttle. No need to worry if you push the C or T button and the Op switch was already set that way.
Martin Myers
Martin...Thanks for the suggestion. Since I don't know how to change the PM42 settings I will assume all the settings are out-of-the-box" default.
Per the PM42 instruction booklet the default sensitivity value/setting is "Standard" for each of the (4) PM42 sections, with the Standard setting the next one up from the lowest "Slow" setting and "Faster and Fastest" the 2 settings higher/quicker than Standard. Assuming the PM42 default short trip value is 3 amps (because I don't know how to change it....) I'm thinking it must be seeing a short current higher than 3 amps when the AR1 trips in line with your suggestion.
I did try moving both AR1 trip pots a bit CCW from the default center position but will test moving one full CCW and adjust accordingly per the AR1 instructions to a point just above the double-trip point of AR1 relay .... .and being a total novice with Digitrax and DCC, simple is better if this does the job .
Will post back with the results...and thanks again!
rrinker What the instructions say is that the reversing section of the PM42 shoudl eb set to faster than the straight short protection section - so it is as you think it should be. The section feeding the AR1 should have the trip delay increased - making it 'slower' to trip. Exact CV depedns on which section of the PM42 feeds the AR1, but unless you've changed anything the PM42 sections will all be set to 'fast'. Try the next slower setting. --Randy
What the instructions say is that the reversing section of the PM42 shoudl eb set to faster than the straight short protection section - so it is as you think it should be.
The section feeding the AR1 should have the trip delay increased - making it 'slower' to trip. Exact CV depedns on which section of the PM42 feeds the AR1, but unless you've changed anything the PM42 sections will all be set to 'fast'. Try the next slower setting.
Appreciate the reply Randy. As I thought - lowering the PM42 trip sensitivity (increase the delay) should solve the timing problem.
But it's the actual "how to do this" that I don't know starting with how to "enter switch control mode on the throttle" stated in the "change PM42 OpSw settings" instructions for slowing/lowering the short circuit sensitivity for each of the (2) track sections with the AR1 return loops.
And compounding my confusion is the "thrown" and "closed" terms Digitrax uses for the respective OpSw states. In my electrical working life the terms "thrown" and "closed" are the same state (circuit connected) of a switch position and the term "open" just that....like the state of a tripped circuit breaker.
Just completed the wiring of my retirement layout with (3) sections of my layout short circuit protected with a PM42. Two of the protected sections include return loops powered by separate AR1 auto reversers fed downstream from the PM42. What I'm running into is random tripping of the respective PM42 circuit breaker for each section with the downstream wired/powered AR1 return loops.
Both AR1's only trip once as they're supposed to as the engine enters or leaves the loop and it is when the AR1 trips that the PM42 circuit breaker kicks out.
My guess is it's a timing situation where the PM42 is sometimes/randomly seeing the momentary short when the AR1 operates. The PM42 instruction card doesn't cover a AR1 fed from an one of the PM42 protected outputs but there is mention of changing the sensitivity to a fast(er) response with a PM42 section configured for auto reversing.
However with my setup with a AR1 fed return loop downstream from the PM42 protected circuit breaker increasing the trip sensitivity seems counter intuitive to me, where a slower response would allow the momentary AR1 short circuit to be "unseen" by the PM42.
Being new to Digitrax DCC I'm totally out of my comfort zone with the PM42 instructions to enter the OPS mode with the DT-402 plugged into it to change the OpSw settings.
If someone has done this I'd more than thankful for a run though on how to change the PM42 trip sensitivity......or would it be best if I called Digitrax support with this?