Tilden wrote: I don't believe the PA programing track has a limiting resistor. I think it only puts out the carrier signal.
I don't believe the PA programing track has a limiting resistor. I think it only puts out the carrier signal.
With DCC that's all there is! It may or may not be current limited, but there is only one signal on the track in any case.
Jeff But it's a dry heat!
As this, the LT1 tester and document are included with all Digitrax command stations and used mainly (as per instructions) for testing purposes, I think they suggest it is applicable to all Digitrax command stations as a voltage limiting test track off rail A and rail B. No were is it stated as limited to the DB150
As per Digitrax :
How do I test a mobile decoder? The LT1 is a simple decoder tester.
LT1 Instructions (.pdf) The LT1 is included with all Digitrax Starter Sets. It consists of a harness with 6 conductor Telco type wire and a male plug, a tester with a female 6 conductor jack and a protection resistor.Features:
I forgot I had read about this and looked it up. 120 Ohm 2 watt is the recommended resistor, if you must.
http://www.digitrax.com/ftp/lt1inst.pdf
We get so confident that we drop this and just test it on the program track. If it reads back, no reason to test it on a test track. The engine MUST allways acknowledge the command station via pulse to motor on the programming track. If it shorts out or anything, you will know.
I found my resistor from my LT1 tester. I had shrink-wrapped the resitor but forgot to identify it. Now I remember.
Thanks.
To actually answer the question, a 20 ohm 2 watt resistor should be fine for a test track. I don't believe the PA programing track has a limiting resistor. I think it only puts out the carrier signal.
I don't have my "test track" hooked up anymore, I use the programming track.
Tilden
All the units with seperate programming track limit the current applied in programming to the bare minimum for acknowledgement. It's an NMRA requirement.
The resistor is like wearing a belt with your suspenders.
Great
thanks
The advance already has a separate program track output that has built in current limiting .no need for a separate resistor.
My test track was taken from an MR article. It has a few pieces of track, a single turnout controlled by a ground throw, a rerailer. I use a center-off DPDT toggle to switch between programming and run on a Zephyr. I have never had a need for a resistor.
But Digitrax does say a 1K resistor could be required between PROG A and PROG B in some cases, Bachmann is an example. Not my case.
http://www.digitrax.com/kb/index.php?a=801
what size of a resister should be used for a test track?